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Papers for Friday, Sep 06 2019

Papers with local authors

I-Non Chiu, Keiichi Umetsu, Ryoma Murata, Elinor Medezinski, Masamune Oguri

22 pages, 16 figures. Submitted to the MNRAS. Comments are welcome

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Paper 19 — arXiv:1909.02042
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Paper 19 — arXiv:1909.02042

We present a statistical weak-lensing magnification analysis on an optically selected sample of 3029 \texttt{CAMIRA} galaxy clusters with richness $N>15$ in the Subaru Hyper Suprime-Cam (HSC) survey. The CAMIRA sample spans a wide redshift range of $0.2\leq z <1.1$. We use two distinct populations of color-selected, flux-limited background galaxies, namely the low-$z$ and high-$z$ samples at mean redshifts of $\approx1.1$ and $\approx1.4$, respectively, from which to measure the weak-lensing magnification signal by accounting for cluster contamination as well as masking effects. Our magnification bias measurements are found to be uncontaminated according to validation tests against the "null-test" samples for which the net magnification bias is expected to vanish. The magnification bias for the full \texttt{CAMIRA} sample is detected at a significance level of $8.29\sigma$, which is dominated by the high-$z$ background. We forward-model the observed magnification data to constrain the richness-to-mass ($N-M$) relation for the \texttt{CAMIRA} sample. In this work, we can only constrain the normalization of the $N-M$ relation by employing informative priors on the mass and redshift trends, and on the intrinsic scatter at fixed mass. The resulting scaling relation is $N\propto {M_{500}}^{0.91\pm0.14} (1 + z)^{-0.45\pm0.75}$, with a characteristic richness of $N=\left(19.63\pm3.16\right)$ and intrinsic log-normal scatter of $0.14\pm0.07$ at $M_{500} = 10^{14}h^{-1}M_{\odot}$. With the derived $N-M$ relation, we provide magnification-calibrated mass estimates of individual \texttt{CAMIRA} clusters, with the typical uncertainty of $\approx38\percent$ and $\approx30\percent$ at richness$\approx20$ and $\approx40$, respectively. We further compare our magnification-inferred $N-M$ relation with those from the shear-based results in the literature, finding good agreement.

All other papers

Prabir Banik, Arunava Bhadra, Madhurima Pandey, Debasish Majumdar

13 pages, four figures. arXiv admin note: text overlap with arXiv:1908.11849

Recent detection of the neutrino events IceCube-170922A, 13 muon-neutrino events observed in 2014-2015 and IceCube-141209A by IceCube observatory from the Blazars, namely TXS 0506+056, PKS 0502+049/TXS 0506+056 and GB6 J1040+0617 respectively in the state of enhanced gamma-ray emission, indicates the acceleration of cosmic rays in the blazar jets. The photo-meson ($p\gamma$) interaction cannot explain the IceCube observations of 13 neutrino events. The non-detection of broadline emission in the optical spectra of the IceCube blazars, however, question the hadronuclear (pp) interaction interpretation through relativistic jet meets with high density cloud. In this work, we investigate the proton blazar model in which the non-relativistic protons that come into existence under the charge neutrality condition of the blazar jet can offer sufficient target matter for $pp$ interaction with shock-accelerated protons, to describe the observed high-energy gamma-rays and neutrino signal from the said blazars. Our findings suggest that the model can explain consistently the observed electromagnetic spectrum in combination with appropriate number of neutrino events from the corresponding blazars.

Istvan I. Racz, Lajos G. Balázs, Zsolt Bagoly, Istvan Horvath, L. Viktor Tóth

arXiv admin note: text overlap with arXiv:1712.00389

Studying the GRBs' gamma-ray spectra may reveal some physical information of Gamma-ray Bursts. The Fermi satellite observed more than two thousand GRBs. The FERMIGBRST catalog contains GRB parameters (peak energy, spectral indices, intensity) estimated for both the total emission (fluence), and the emission during the interval of the peak flux. We found a relationship with linear discriminant analysis between the spectral categories and the model independent physical data. We compared the Swift and Fermi spectral types. We found a connection between the Fermi fluence spectra and the Swift spectra but the result of the peak flux spectra can be disputable. We found that those GRBs which were observed by both Swift and Fermi can similarly discriminate as the complete Fermi sample. We concluded that the common observation probably did not mean any trace of selection effects in the spectral behavior of GRBs.

T. Baug, Richard de Grijs, L. K. Dewangan, Gregory J. Herczeg, D. K. Ojha, Ke Wang, Licai Deng, B. C. Bhatt

24 pages, 15 figures (4 additional figures in Appendix), 3 tables, Accepted for publication in the Astrophysical Journal

We investigate the influence of Wolf-Rayet (W-R) stars on their surrounding star-forming molecular clouds. We study five regions containing W-R stars in the inner Galactic plane ($l\sim$[14$^\circ$-52$^\circ$]), using multi-wavelength data from near-infrared to radio wavelengths. Analysis of $^{13}$CO line data reveals that these W-R stars have developed gas-deficient cavities in addition to molecular shells with expansion velocities of a few km s$^{-1}$. The pressure owing to stellar winds primarily drives these expanding shells and sweeps up the surrounding matter to distances of a few pc. The column densities of shells are enhanced by a minimum of 14% for one region to a maximum of 88% for another region with respect to the column densities within their central cavities. No active star formation - including molecular condensations, protostars, or ionized gas - is found inside the cavities, whereas such features are observed around the molecular shells. Although the expansion of ionized gas is considered an effective mechanism to trigger star formation, the dynamical ages of the HII regions in our sample are generally not sufficiently long to do so efficiently. Overall, our results hint at the possible importance of negative W-R wind-driven feedback on the gas-deficient cavities, where star formation is quenched as a consequence. In addition, the presence of active star formation around the molecular shells indicates that W-R stars may also assist in accumulating molecular gas, and that they could initiate star formation around those shells.

D. Föhring, R. W. Wilson, J. Osborn, V. S. Dhillon

Accepted for publication in MNRAS. 12 pages, 13 figures

Atmospheric scintillation caused by optical turbulence in the Earth's atmosphere can be the dominant source of noise in ground-based photometric observations of bright targets, which is a particular concern for ground-based exoplanet transit photometry. We demonstrate the implications of atmospheric scintillation for exoplanet transit photometry through contemporaneous turbulence profiling and transit observations. We find a strong correlation between measured intensity variations and scintillation determined through optical turbulence profiling. This correlation indicates that turbulence profiling can be used to accurately model the amount of scintillation noise present in photometric observations on another telescope at the same site. We examine the conditions under which scintillation correction would be beneficial for transit photometry through turbulence profiling, and find that for the atmosphere of La Palma, scintillation dominates for bright targets of magnitude above $V\sim10.1$ mag for a 0.5~m telescope, and at $V\sim11.7$ mag for a 4.2 m telescope under median atmospheric conditions. Through Markov-chain Monte Carlo methods we examine the effect of scintillation noise on the uncertainty of the measured exoplanet parameters, and determine the regimes where scintillation correction is especially beneficial. The ability to model the amount of noise in observations due to scintillation, given an understanding of the atmosphere, is a crucial test for our understanding of scintillation and the overall noise budget of our observations.

Johann Brehmer, Siddharth Mishra-Sharma, Joeri Hermans, Gilles Louppe, Kyle Cranmer

22 pages, 6 figures, code available at this https URL

The subtle and unique imprint of dark matter substructure on extended arcs in strong lensing systems contains a wealth of information about the properties and distribution of dark matter on small scales and, consequently, about the underlying particle physics. However, teasing out this effect poses a significant challenge since the likelihood function for realistic simulations of population-level parameters is intractable. We apply recently-developed simulation-based inference techniques to the problem of substructure inference in galaxy-galaxy strong lenses. By leveraging additional information extracted from the simulator, neural networks are efficiently trained to estimate likelihood ratios associated with population-level parameters characterizing substructure. Through proof-of-principle application to simulated data, we show that these methods can provide an efficient and principled way to simultaneously analyze an ensemble of strong lenses, and can be used to mine the large sample of lensing images deliverable by near-future surveys for signatures of dark matter substructure.

Numerical simulations of dust-gas dynamics are one of the fundamental tools in astrophysical research, such as the study of star and planet formation. It is common to find tightly coupled dust and gas in astrophysical systems, which demands that any practical integration method be able to take time steps $\Delta t$ much longer than the stopping time $t_{\rm s}$ due to drag. A number of methods have been developed to ensure stability in this stiff ($\Delta t\gg t_{\rm s}$) regime, but there remains large room for improvement in terms of accuracy. In this paper, we describe an easy-to-implement method, the "staggered semi-analytic method" (SSA), and conduct numerical tests to compare it to other implicit and semi-analytic methods, including the $2^{\rm nd}$ order implicit method and the Verlet method. SSA makes use of a staggered step to better approximate the terminal velocity in the stiff regime. In applications to protoplanetary disks, this not only leads to orders-of-magnitude higher accuracy than the other methods, but also provides greater stability, making it possible to take time steps 100 times larger in some situations. SSA is also $2^{\rm nd}$ order accurate and symplectic when $\Delta t \ll t_{\rm s}$. More generally, the robustness of SSA makes it applicable to linear dust-gas drag in virtually any context.

Charlie Conroy, Rohan P. Naidu, Dennis Zaritsky, Ana Bonaca, Phillip Cargile, Benjamin D. Johnson, Nelson Caldwell

12 pages, 9 figures, submitted from Travelers to ApJ

The Galactic stellar halo is predicted to have formed at least partially from the tidal disruption of accreted dwarf galaxies. This assembly history should be detectable in the orbital and chemical properties of stars. The H3 Survey is obtaining spectra for 200,000 stars, and, when combined with Gaia data, is providing detailed orbital and chemical properties of Galactic halo stars. Unlike previous surveys of the halo, the H3 target selection is based solely on magnitude and Gaia parallax; the survey therefore provides a nearly unbiased view of the entire stellar halo at high latitudes. In this paper we present the distribution of stellar metallicities as a function of Galactocentric distance and orbital properties for a sample of 4232 kinematically-selected halo giants to 100 kpc. The stellar halo is relatively metal-rich, [Fe/H]=-1.2, and there is no discernable metallicity gradient over the range $6<R_{\rm gal}<100$ kpc. However, the halo metallicity distribution is highly structured including distinct metal-rich and metal-poor components at $R_{\rm gal}<10$ kpc and $R_{\rm gal}>30$ kpc, respectively. Metal-poor stars with [Fe/H]$<-2$ are a small population of the halo at all distances and orbital categories. We associate the "in-situ" stellar halo with stars displaying thick-disk chemistry on halo-like orbits; such stars are confined to $|z|<10$ kpc. The majority of the stellar halo is resolved into discrete features in orbital-chemical space, suggesting that the bulk of the stellar halo formed from the accretion and tidal disruption of dwarf galaxies. (ABRIDGED)

Yiping Shu, Sergey E. Koposov, N. Wyn Evans, Vasily Belokurov, Richard G. McMahon, Matthew W. Auger, Cameron A. Lemon

18 pages+appendice, 11 figures, 2 tables, accepted by MNRAS. The C75 AGN catalogue can be downloaded at this https URL

We present two catalogues of active galactic nucleus (AGN) candidates selected from the latest data of two all-sky surveys -- Data Release 2 (DR2) of the \emph{Gaia} mission and the unWISE catalogue of the \emph{Wide-field Infrared Survey Explorer} (\emph{WISE}). We train a random forest classifier to predict the probability of each source in the \emph{Gaia}-unWISE joint sample being an AGN, $P_{\rm RF}$, based on \emph{Gaia} astrometric and photometric measurements and unWISE photometry. The two catalogues, which we designate C75 and R85, are constructed by applying different $P_{\rm RF}$ threshold cuts to achieve an overall completeness of 75\% ($\approx$90\% at \emph{Gaia} $G\leq20$ mag) and reliability of 85\% respectively. The C75 (R85) catalogue contains 2,734,464 (2,182,193) AGN candidates across the effective 36,000 deg$^2$ sky, of which $\approx$0.91 (0.52) million are new discoveries. Photometric redshifts of the AGN candidates are derived by a random forest regressor using \emph{Gaia} and \emph{WISE} magnitudes and colours. The estimated overall photometric redshift accuracy is 0.11. Cross-matching the AGN candidates with a sample of known bright cluster galaxies, we identify a high-probability strongly-lensed AGN candidate system, SDSS\,J1326$+$4806, with a large image separation of 21\farcs06. All the AGN candidates in our catalogues will have $\sim$5-year long light curves from \emph{Gaia} by the end of the mission, and thus will be a great resource for AGN variability studies. Our AGN catalogues will also be helpful in AGN target selections for future spectroscopic surveys, especially ones in the southern hemisphere. The C75 catalogue can be downloaded at https://www.ast.cam.ac.uk/~ypshu/AGN_Catalogues.html.

Stacy McGaugh, Federico Lelli, Pengfei Li, Jim Schombert

8 pages, 6 figures; invited review for IAU Symposium 353: Galactic Dynamics in the Era of Large Surveys

Galaxies are observed to obey a strict set of dynamical scaling relations. We review these relations for rotationally supported disk galaxies spanning many decades in mass, surface brightness, and gas content. The behavior of these widely varied systems can be summarized with a handful of empirical laws connected by a common acceleration scale.

Jeffrey K. Ratzloff, Brad N. Barlow, Thomas Kupfer, Kyle A. Corcoran, Stephan Geier Evan Bauer, Henry T. Corbett, Ward S. Howard, Amy Glazier, Nicholas M. Law

14 pages, 11 figures

We present EVR-CB-001, the discovery of a compact binary with an extremely low mass ($.21 \pm 0.05 M_{\odot}$) helium core white dwarf progenitor (pre-He WD) and an unseen low mass ($.32 \pm 0.06 M_{\odot}$) helium white dwarf (He WD) companion. He WDs are thought to evolve from the remnant helium-rich core of a main-sequence star stripped during the giant phase by a close companion. Low mass He WDs are exotic objects (only about .2$\%$ of WDs are thought to be less than .3 $M_{\odot}$), and are expected to be found in compact binaries. Pre-He WDs are even rarer, and occupy the intermediate phase after the core is stripped, but before the star becomes a fully degenerate WD and with a larger radius ($\approx .2 R_{\odot}$) than a typical WD. The primary component of EVR-CB-001 (the pre-He WD) was originally thought to be a hot subdwarf (sdB) star from its blue color and under-luminous magnitude, characteristic of sdBs. The mass, temperature ($T_{\rm eff}=18,500 \pm 500 K$), and surface gravity ($\log(g)=4.96 \pm 0.04$) solutions from this work are lower than values for typical hot subdwarfs. The primary is likely to be a post-RGB, pre-He WD contracting into a He WD, and at a stage that places it nearest to sdBs on color-magnitude and $T_{\rm eff}$-$\log(g)$ diagrams. EVR-CB-001 is expected to evolve into a fully double degenerate, compact system that should spin down and potentially evolve into a single hot subdwarf star. Single hot subdwarfs are observed, but progenitor systems have been elusive.

Richa Kundu, José G. Fernández-Trincado, Dante Minniti, Harinder P. Singh, Edmundo Moreno, Céline Reylé, Annie C. Robin, Mario Soto

10 pages, 4 figures, 3 tables. Accepted to the Monthly Notices of the Royal Astronomical Society

We report the identification of possible extended star debris candidates beyond the cluster tidal radius of NGC 6362 based on the second {\it Gaia} data release ({\it Gaia} DR2). We found 259 objects possibly associated with the cluster lying in the vicinity of the giant branch and 1--2 magnitudes fainter/brighter than the main-sequence turn-off in the cluster color-magnitude diagram and which cover an area on the sky of $\sim$4.1 deg$^{2}$ centered on the cluster. We traced back the orbit of NGC 6362 in a realistic Milky-Way potential, using the \texttt{GravPot16} package, for 3 Gyrs. The orbit shows that the cluster shares similar orbital properties as the inner disk, having peri-/apo-galactic distances, and maximum vertical excursion from the Galactic plane inside the corotation radius (CR), moving inwards from CR radius to visit the inner regions of the Milky Way. The dynamical history of the cluster reveals that it has crossed the Galactic disk several times in its lifetime and has recently undergone a gravitational shock, $\sim 15.9$ Myr ago, suggesting that less than 0.1\% of its mass has been lost during the current disk-shocking event. Based on the cluster's orbit and position in the Galaxy, we conclude that the possible extended star debris candidates are a combined effect of the shocks from the Galactic disk and evaporation from the cluster. Lastly, the evolution of the vertical component of the angular momentum shows that the cluster is strongly affected dynamically by the Galactic bar potential.

Daniel R. Weisz, Andrew E. Dolphin, Nicolas F. Martin, Saundra M. Albers, Michelle L. M. Collins, Annette M. N. Ferguson, Geraint F. Lewis, A. Dougal Mackey, Alan McConnachie, R. Michael Rich, Evan D. Skillman

8 pages, 3 figures. Accepted for publication in MNRAS

We present new horizontal branch (HB) distance measurements to 17 of the faintest known M31 satellites ($-6 \lesssim M_{V} \lesssim -13$) based on deep Hubble Space Telescope (HST) imaging. The color-magnitude diagrams extend $\sim$1-2 magnitudes below the HB, which provides for well-defined HBs, even for faint galaxies in which the tip of the red giant branch (TRGB) is sparsely populated. We determine distances across the sample to an average precision of 4% ($\sim 30$~kpc at $800$~kpc). We find that the majority of these galaxies are in good agreement, though slightly farther (0.1-0.2 mag) when compared to recent ground-based TRGB distances. Two galaxies (And~IX and And~XVII) have discrepant HST and ground-based distances by $\sim 0.3$ mag ($\sim 150$~kpc), which may be due to contamination from Milky Way foreground stars and/or M31 halo stars in sparsely populated TRGB regions. We use the new distances to update the luminosities and structural parameters for these 17 M31 satellites. The new distances do not substantially change the spatial configuration of the M31 satellite system. We comment on future prospects for precise and accurate HB distances for faint galaxies in the Local Group and beyond.

Gabriel Germán, Juan Carlos Hidalgo, Francisco X. Linares Cedeño, Ariadna Montiel, J. Alberto Vázquez

8 pages, 2 tables, 5 figures

We study a model of inflation based on $\mathcal{N}=1$ supergravity essentially depending on one effective parameter. Under a field transformation we show that this model turns out to be equivalent to a previously studied supergravity model known to be ruled out with the original choice of the parameter. Such parameter measures the slope of the potential at observable scales. Through a Bayesian parameter estimation, it is shown how this model is compatible with recent CMB temperature measurements by {\it Planck 2018} giving rise to a simple, viable, single field model of inflation. The tensor to scalar ratio constraint is found to be $r_{0.002}<0.065$ with negative running. We discuss how observables are invariant under the field transformation which leaves unaltered the slow-roll parameters. As a consequence the use of one presentation of the model or its field-transformed version is purely a matter of convenience.

Wei Wei, E. A. Huerta, Bradley C. Whitmore, Janice C. Lee, Stephen Hannon, Rupali Chandar, Daniel A. Dale, Kirsten L. Larson, David A. Thilker, Leonardo Ubeda, Médéric Boquien, Mélanie Chevance, J. M. Diederik Kruijssen, Andreas Schruba, Guillermo Blanc, Enrico Congiu

13 pages, 5 figures, 2 appendices. Submitted to MNRAS

We present the results of a proof-of-concept experiment which demonstrates that deep learning can successfully be used for production-scale classification of compact star clusters detected in HST UV-optical imaging of nearby spiral galaxies in the PHANGS-HST survey. Given the relatively small and unbalanced nature of existing, human-labelled star cluster datasets, we transfer the knowledge of neural network models for real-object recognition to classify star clusters candidates into four morphological classes. We show that human classification is at the 66%:37%:40%:61% agreement level for the four classes considered. Our findings indicate that deep learning algorithms achieve 76%:63%:59%:70% for a star cluster sample within 4Mpc < D <10Mpc. We tested the robustness of our deep learning algorithms to generalize to different cluster images using the first data obtained by PHANGS-HST of NGC1559, which is more distant at D = 19Mpc, and found that deep learning produces classification accuracies 73%:42%:52%:67%. We furnish evidence for the robustness of these analyses by using two different neural network models for image classification, trained multiple times from the ground up to assess the variance and stability of our results. We quantified the importance of the NUV, U, B, V and I images for morphological classification with our deep learning models, and find that the V-band is the key contributor as human classifications are based on images taken in that filter. This work lays the foundations to automate classification for these objects at scale, and the creation of a standardized dataset.

Dennis Zaritsky, Charlie Conroy, Huanian Zhang, Ana Bonaca, Nelson Caldwell, Phillip A. Cargile, Benjamin D. Johnson, Rohan P. Naidu

8 pages, submitted for publication

The timing argument provides a lower limit on the mass of the Milky Way. We find, using a sample of 32 stars at $R > 60$ kpc drawn from the H3 Spectroscopic Survey and mock catalogs created from published numerical simulations, that M$_{200} > 0.91\times 10^{12}$ M$_\odot$ with 90% confidence. We recommend using this limit to refine the allowed prior mass range in more complex and sophisticated statistical treatments of Milky Way dynamics. The use of such a prior would have significantly reduced many previously published uncertainty ranges. Our analysis suggests that the most likely value of M$_{200}$ is $\sim 1.4 \times 10^{12}$ M$_\odot$, but establishing this as the Milky Way mass requires a larger sample of outer halo stars and a more complete analysis of the inner halo stars in H3. The imminent growth in the sample of outer halo stars due to ongoing and planned surveys will make this possible.

Minju M. Lee, Ichi Tanaka, Ryohei Kawabe, Itziar Aretxaga, Bunyo Hatsukade, Takuma Izumi, Masaru Kajisawa, Tadayuki Kodama, Kotaro Kohno, Kouichiro Nakanishi, Toshiki Saito, Ken-ichi Tadaki, Yoichi Tamura, Hideki Umehata, Milagros Zeballos

27 pages, 10 figures, 4 tables, ApJ in press

We present a study of the gas kinematics of star-forming galaxies associated with protocluster 4C 23.56 at $z=2.49$ using $0''.4$ resolution CO (4-3) data taken with ALMA. Eleven H$\alpha$ emitters (HAEs) are detected in CO (4-3), including six HAEs that were previously detected in CO (3-2) at a coarser angular resolution. The detections in both CO lines are broadly consistent in the line widths and the redshifts, confirming both detections. With an increase in the number of spectroscopic redshifts, we confirm that the protocluster is composed of two merging groups with a total halo mass of $\log{(M_{\rm cl}/M_{\odot})} =13.4-13.6$, suggesting that the protocluster would evolve into a Virgo-like cluster ($>10^{14} M_{\odot}$). We compare the CO line widths and the CO luminosities with galaxies in other (proto)clusters ($n_{\rm gal}=91$) and general fields ($n_{\rm gal}=80$) from other studies. The 4C23.56 protocluster galaxies have CO line widths and luminosities comparable to other protocluster galaxies on average. On the other hand, the CO line widths are on average broader by $\approx50\%$ compared to field galaxies, while the median CO luminosities are similar. The broader line widths can be attributed to both effects of unresolved gas-rich mergers and/or compact gas distribution, which is supported by our limited but decent angular resolution observations and the size estimate of three galaxies. Based on these results, we argue that gas-rich mergers may play a role in the retention of the specific angular momentum to a value similar to that of field populations during cluster assembly, though we need to verify this with a larger number of samples.

Arthur D. Bosman, Andrea Banzatti, Simon Bruderer, Alexander G.G. M. Tielens, Geoffrey A. Blake, Ewine F. van Dishoeck

17 pages, 16 figures, accepted by A&A

[abridged]CO rovibrational lines are efficient probes of warm molecular gas and can give unique insights into the inner 10 AU of proto-planetary disks. Recent studies have found a relation between the ratio of lines originating from the second and first vibrationally excited state, denoted as $v2/v1$, and the emitting radius of CO. In disks around Herbig Ae stars the vibrational excitation is low when CO lines come from close to the star, and high when lines only probe gas at large radii (more than 5 AU). We aim to find explanations for the observed trends between CO vibrational ratio, emitting radii, and NIR excess, and identify their implications in terms of the physical and chemical structure of inner disks around Herbig stars. Slab models and full disk thermo chemical models are calculated. Simulated observations from the models are directly compared to the data. Broad CO lines with low vibrational ratios are best explained by a warm (400-1300 K) inner disk surface with gas-to-dust ratios below 1000; no CO is detected within/at the inner dust rim, due to dissociation at high temperatures. In contrast, explaining the narrow lines with high vibrational ratios requires an inner cavity of a least 5 AU in both dust and gas, followed by a cool (100-300 K) molecular gas reservoir with gas-to-dust ratios greater than 10000 at the cavity wall. In all cases the CO gas must be close to thermalization with the dust. The high gas-to-dust ratios needed to explain high $v2/v1$ in narrow CO lines for a subset of group I disks can naturally be interpreted as due to the dust traps that have been proposed to explain millimeter dust cavities. The broad lines seen in most group II objects indicate a very flat disk in addition to inner disk substructures within 10 AU that can be related to the substructures recently observed with ALMA.

Patrick Heix, Serap Tilav, Christopher Wiebusch, Marit Zöcklein (for the IceCube Collaboration)

Presented at the 36th International Cosmic Ray Conference (ICRC 2019). See arXiv:1907.11699 for all IceCube contributions

The IceCube Neutrino Observatory detects atmospheric muon neutrinos above 100 GeV at a rate of about 100 000 per year. These neutrinos originate from decays of charged pions and kaons in cosmic ray air showers. Their flux depends on the probability of production and decay of the parent mesons, and is thus sensitive to the stratospheric temperature. Neutrino rates from 8 years of operation of the detector are correlated with the atmospheric temperature profile as measured by the Atmospheric Infrared Sounder (AIRS). An analysis of this correlation provides a test of models of hadronic interactions in atmospheric air showers. This analysis of neutrinos complements the analysis of the correlation of atmospheric muons with temperature that is presented in another paper at this conference.

Dirk Heinen, Shefali, Roxanne Turcotte, Lars Steffen Weinstock, Christopher Wiebusch, Simon Zierke (for the IceCube Collaboration)

Presented at the 36th International Cosmic Ray Conference (ICRC 2019). See arXiv:1907.11699 for all IceCube contributions

The IceCube Neutrino Observatory will be upgraded with about 700 additional optical sensor modules and new calibration devices. Particularly, improved calibration will enhance IceCube's physics capabilities both at low and high neutrino energies. An important ingredient for a good angular resolution of the observatory is a precise calibration of the positions of optical sensors. We present the concept of newly developed acoustic sensors that are mounted inside the optical modules and additional acoustic emitter modules that are attached to the strings. With this system we aim for the calibration of the detectors' geometry with a precision of 10\,cm by means of trilateration of the arrival times of acoustic signals. This new method will allow for an improved and complementary geometry calibration with respect to previously used methods based on optical flashers and drill logging data.

F. R. Ferraro (1, 2), B. Lanzoni (1, 2), E. Dalessandro (2), M. Cadelano (1, 2), S. Raso (1, 2), A. Mucciarelli (1, 2), G. Beccari (3), C. Pallanca (1, 2)- (1 Bologna University, Italy, 2 INAF-OAS, Bologna, Italy, 3 ESO, Germany)

In press in Nature Astronomy, 9 September 2019 issue. 24 pages, 7 figures, 2 tables

The distribution of size as a function of age observed for star clusters in the Large Magellanic Cloud (LMC) is very puzzling: young clusters are all compact, while the oldest systems show both small and large sizes. It is commonly interpreted as due to a population of binary black holes driving a progressive expansion of cluster cores. Here we propose, instead, that it is the natural consequence of the fact that only relatively low-mass clusters have formed in the last ~3 Gyr in the LMC and only the most compact systems survived and are observable. The spread in size displayed by the oldest (and most massive) clusters, instead, can be explained in terms of initial conditions and internal dynamical evolution. To quantitatively explore the role of the latter, we selected a sample of five coeval and old LMC clusters with different sizes, and we estimated their dynamical age from the level of central segregation of blue straggler stars (the so-called dynamical clock). Similarly to what found in the Milky Way, we indeed measure different levels of dynamical evolution among the selected coeval clusters, with large-core systems being dynamically younger than those with small size. This behaviour is fully consistent with what expected from internal dynamical evolution processes over timescales mainly set by the structure of each system at formation.

We present the detection and imaging of the spatially resolved shell of nova V382 Vel with SOAR adaptive optics module (SAM). The shell was observed in narrow band filters H$\alpha$ and [O III] 5007\AA, revealing different structures in each filter. The shell's angular diameter obtained was $9.9$ arcsec, equivalent to $2.8 \times 10^{17}$ cm, using the distance of $1.79$ kpc obtained by Gaia mission. The upper limit for total shell mass derived from recombination lines is $M_{s} = 1.4 \times 10^{-4}$ M$_{\odot}$. Our photoionization models indicate an accretion disk with $T_d=60,000$ K and L=$10^{36}$ erg/s as main ionizing source.

Ying-Yi Song, Mario Mateo, A. D. Mackey, Edward W. Olszewski, Ian U. Roederer, Matthew G. Walker, John I. Bailey III

24 pages, 15 figures, 10 tables, accepted for publication in MNRAS

As an introduction of a kinematic survey of Magellanic Cloud (MC) star clusters, we report on the dynamical masses and mass-to-light ($M/L$) ratios of NGC 419 (SMC) and NGC 1846 (LMC). We have obtained more than one hundred high-resolution stellar spectra in and around each cluster using the multi-object spectrograph M2FS on the $Magellan$/Clay Telescope. Line-of-sight velocities and positions of the stars observed in each cluster were used as input to an expectation-maximization algorithm used to estimate cluster membership probabilities, resulting in samples of 46 and 52 likely members ($P_{M}\geq 50$%) in NGC 419 and NGC 1846, respectively. This process employed single-mass King models constrained by the structural parameters of the clusters and provided self-consistent dynamical mass estimates for both clusters. Our best-fit results show that NGC 419 has a projected central velocity dispersion of $2.44^{+0.37}_{-0.21}\ {\rm km\,s^{-1}}$, corresponding to a total mass of $7.6^{+2.5}_{-1.3}\times10^4\ {\rm M}_{\odot}$ and $V$-band $M/L$ ratio of $0.22^{+0.08}_{-0.05}$ in solar units. For NGC 1846, the corresponding results are $2.04^{+0.28}_{-0.24}\ {\rm km\,s^{-1}}$, $5.4^{+1.5}_{-1.4}\times10^4\ {\rm M}_{\odot}$ and $0.32^{+0.11}_{-0.11}$. The mean metallicities of NGC 419 and NGC 1846 are found to be $\rm [Fe/H]=-0.84\pm0.19$ and $-0.70\pm0.08$, respectively, based on the spectra of likely cluster members. We find marginal statistical evidence of rotation in both clusters, though in neither cluster does rotation alter our mass estimates significantly. We critically compare our findings with those of previous kinematic studies of these two clusters in order to evaluate the consistency of our observational results and analytic tools.

William T. Reach, Le Ngoc Tram, Matthew Richter, Antoine Gusdorf, Curtis DeWitt

accepted by ApJ (9/4/2019)

Supernovae from core-collapse of massive stars drive shocks into the molecular clouds from which the stars formed. Such shocks affect future star formation from the molecular clouds, and the fast-moving, dense gas with compressed magnetic fields is associated with enhanced cosmic rays. This paper presents new theoretical modeling, using the Paris-Durham shock model, and new observations, using the Stratospheric Observatory for Infrared Astronomy (SOFIA), of the H$_2$ S(5) pure rotational line from molecular shocks in the supernova remnant IC443. We generate MHD models for non-steady-state shocks driven by the pressure of the IC443 blast wave into gas of densities $10^3$ to $10^5$ cm$^{-3}$. We present the first detailed derivation of the shape of the velocity profile for emission from H$_2$ lines behind such shocks, taking into account the shock age, preshock density, and magnetic field. For preshock densities $10^3$-$10^5$ cm$^{-3}$, the the predicted shifts of line centers, and the line widths, of the H$_2$ lines range from 20-2, and 30-4 km/s, respectively. The a priori models are compared to the observed line profiles, showing that clumps C and G can be explained by shocks into gas with density 10$^3$ to $2\times 10^4$ cm$^{-3}$ and strong magnetic fields. For clump B2 (a fainter region near clump B), the H$_2$ spectrum requires a J-type shock into moderate density (~100 cm$^{-3}$) with the gas accelerated to 100 km/s from its pre-shock location. Clump B1 requires both a magnetic-dominated C-type shock (like for clumps C and G) and a J-type shock (like for clump B1) to explain the highest observed velocities. The J-type shocks that produce high-velocity molecules may be locations where the magnetic field is nearly parallel to the shock velocity, which makes it impossible for a C-type shock (with ions and neutrals separated) to form.

Michael Combi, Yinsi Shou, Nicolas Fougere, Valeriy Tenishev, Kathrin Altwegg, Martin Rubin, Dominique Bockelée-Morvan, Fabrizio Capaccioni, Yu-Chi Cheng, Uwe Fink, Tamas Gombosi, Kenneth C. Hansen, Zhenguang Huang, David Marshall, Gabor Toth

144 pages, 9 figures, 8 tables, 1 supplemental table

The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) suite of instruments operated throughout the over two years of the Rosetta mission operations in the vicinity of comet 67P/Churyumov-Gerasimenko. It measured gas densities and composition throughout the comet's atmosphere, or coma. Here we present two-years' worth of measurements of the relative densities of the four major volatile species in the coma of the comet, H2O. CO2, CO and O2, by one of the ROSINA sub-systems called the Double Focusing Mass Spectrometer (DFMS). The absolute total gas densities were provided by the Comet Pressure Sensor (COPS), another ROSINA sub-system. DFMS is a very high mass resolution and high sensitivity mass spectrometer able to resolve at a tiny fraction of an atomic mass unit. We have analyzed the combined DFMS and COPS measurements using an inversion scheme based on spherical harmonics that solves for the distribution of potential surface activity of each species as the comet rotates, changing solar illumination, over short intervals and as the comet changes distance from the sun and orientation of its spin axis over long time intervals. We also use the surface boundary conditions derived from the inversion scheme to simulate the whole coma with our fully kinetic Direct Simulation Monte Carlo model and calculate the production rates of the four major species throughout the mission. We compare the derived production rates with revised remote sensing observations by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) as well as with published observations from the Microwave Instrument for the Rosetta Orbiter (MIRO). Finally we use the variation of the surface production of the major species to calculate the total mass loss over the mission and, for different estimates of the dust/gas ratio, calculate the variation of surface loss over the nucleus.

Malgosia Sobolewska, Aneta Siemiginowska, Matteo Guainazzi, Martin Hardcastle, Giulia Migliori, Luisa Ostorero, Lukasz Stawarz

7 pages, 3 figures, ApJ, in press

Compact Symmetric Objects (CSOs) have been observed with Chandra and XMM-Newton to gain insights into the initial stages of a radio source evolution and probe the black hole activity at the time of relativistic outflow formation. However, there have been no CSO observations to date at the hard X-ray energies (> 10 keV), impeding our ability to robustly constrain the properties of the intrinsic X-ray emission and of the medium surrounding the young expanding jets. We present the first hard X-ray observation of a CSO performed with NuSTAR. Our target, OQ+208, is detected up to 30 keV, and thus we establish CSOs as a new class of NuSTAR sources. We analyze the NuSTAR data jointly with our new Chandra and archival XMM-Newton data and find that a young, ~250 years old, radio jet spanning the length of ~10 pc coexists with cold obscuring matter, consistent with a dusty torus, with an equivalent hydrogen column density $N_H = 10^{23}$-$10^{24}$ cm$^{-2}$. The primary X-ray emission is characterized by a photon index $\Gamma \sim 1.45$ and intrinsic 0.5-30 keV luminosity $L \sim 10^{43}$ erg s$^{-1}$. The results of our spectral modeling and broad-line optical classification of the source suggest a porous structure of the obscuring torus. Alternatively, the source may belong to the class of optically un-obscured/X-ray obscured AGN. The observed X-ray emission is too weak compared to that predicted by the expanding radio lobes model, leaving an accretion disk corona or jets as the possible origins of the X-ray emission from this young radio galaxy.

Matthew Kolopanis, Daniel C. Jacobs, Carina Cheng, Aaron R. Parsons, Saul A. Kohn, Jonathan C. Pober, James E. Aguirre, Zaki S. Ali, Gianni Bernardi, Richard F. Bradley, Christopher L. Carilli, David R. DeBoer, Matthew Dexter, Joshua S. Dillon, Joshua Kerrigan, Patricia Klima, Adrian Liu, Dave MacMahon, David F. Moore, Nithyanandan Thyagarajan, Chuneeta Devi Nunhokee, William Walbrughp, Andre Walker

28 Pages, 17 Pages, Accepted to APJ

We present limits on the 21cm power spectrum from the Epoch of Reionization (EoR) using data from the 64 antenna configuration of the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) analyzed through a power spectrum pipeline independent from previous PAPER analyses. Previously reported results from PAPER have been found to contain significant signal loss (Cheng et al. 2018, arxiv:1810.05175). Several lossy steps from previous PAPER pipelines have not been included in this analysis, namely: delay-based foreground filtering, optimal fringe-rate filtering, and empirical covariance-based estimators. Steps which remain in common with previous analyses include redundant calibration and local sidereal time (LST) binning. The power spectra reported here are effectively the result of applying a linear Fourier transform analysis to the calibrated, LST binned data. This analysis also uses more data than previous publications, including the complete available redshift range of $z \sim 7.5$ to $11$. In previous PAPER analyses, many power spectrum measurements were found to be detections of noncosmological power at levels of significance ranging from two to hundreds of times the theoretical noise. Here, excess power is examined using redundancy between baselines and power spectrum jackknives. The upper limits we find on the 21cm power spectrum from reionization are ($1500$ mK)$^{2}$, ($1900$ mK)$^{2}$, ($280$ mK)$^{2}$, ($200$ mK)$^{2}$, ($380$ mK)$^{2}$, ($300$ mK)$^{2}$ at redshifts $z=10.87,\ 9.93,\ 8.68,\ 8.37,\ 8.13,$ and $7.48$, respectively. For reasons described in Cheng et al. 2018 (arxiv:1810.05175), these limits supersede all previous PAPER results (Ali et al. 2018, arxiv:1502.06016).

Michael C. Stroh, Ylva M. Pihlström, Loránt O. Sjouwerman, Megan O. Lewis, Mark J Claussen, Mark R. Morris, R. Michael Rich

25 pages, 16 figures

We report on the first 1,432 sources observed using the Atacama Large Millimeter/submillimeter Array (ALMA), from the Bulge Asymmetries and Dynamical Evolution (BAaDE) survey, which aims to obtain tens of thousands of line-of-sight velocities from SiO masers in Asymptotic Giant Branch (AGB) stars in the Milky Way. A 71% detection rate of 86 GHz SiO masers is obtained from the infrared color-selected sample, and increases to 80% when considering the likely oxygen-rich stars using Midcourse Space Experiment (MSX) colors isolated in a region where [D]-[E] <= 1.38. Based on Galactic distributions, the presence of extended CS emission, and likely kinematic associations, the population of sources with [D]-[E] > 1.38 probably consists of young stellar objects, or alternatively, planetary nebulae. For the SiO detections we examined whether individual SiO transitions provide comparable stellar line-of-sight velocities, and found that any SiO transition is suitable for determining a stellar AGB line-of-sight velocity. Finally, we discuss the relative SiO detection rates and line strengths in the context of current pumping models.

We report the detection in Chandra ACIS archival data of an elongated soft (<3 keV) X-ray feature tp the south of the Compton Thick Active Galactic Nucleus (CT AGN) galaxy IC 2497, coincident with the emission feature known as Hanny's Voorwerp (HV). The data are consistent with the spatial correspondence between X-ray, optical emission line, and radio features detected in nearby obscured AGNs (e.g., ESO 428-G014). The X-ray luminosity of the (0.3-3.0 keV) soft feature is ~1.2x10^40 erg/s. We infer an [OIII]/Soft-X-ray ratio in the range of ~200, consistent with the highest values measured in some of the clouds of NGC 4151. Overall, given the uncertainties, Hanny's Voorwerp appears to be a feature consistent with the ionization cone emission of nearby AGNs. We estimate an X-ray recombination time of 2x10^7 yr, longer than the [OIII] recombination time (~8000 yr). This suggests that extended soft X-ray components may be a better diagnostic of overall long-term activity, while detection of an [OIII] HV would point to a time-limited activity burst.

R. Basu Thakur (California Institute of Technology, Jet Propulsion laboratory), N. Klimovich (California Institute of Technology, Jet Propulsion laboratory), P. K . Day (California Institute of Technology, Jet Propulsion laboratory), E. Shirokoff (University of Chicago), P. D. Mauskopf (Arizona State University), F. Faramarzi (Arizona State University), P. S. Barry (Argonne National Laboratory)

Kinetic inductance in thin film superconductors has been used as the basis for low-temperature, low-noise photon detectors. In particular thin films such as NbTiN, TiN, NbN, the kinetic inductance effect is strongly non-linear in the applied current, which can be utilized to realize novel devices. We present results from transmission lines made with these materials, where DC (current) control is used to modulate the phase velocity thereby enabling an on-chip spectrometer. The utility of such compact spectrometers are discussed, along with their natural connection with parametric amplifiers.

Michael B. Lund, Savannah R. Jacklin, David Ciardi

10 pages, 3 figures, APC State of the Profession White Paper submitted to the Astro2020 Decadal Survey (Additional endorsers listed in article)

Earning any advanced degree in physics or astronomy is an arduous process and major accomplishment. However, not every journey to the Ph.D. is paved equally. Every year, there are hundreds of students who earn terminal master's degrees in physics and astronomy in the United States. A master's degree on its own is sufficient qualification for many good careers, but for a portion of these students, the master's degree is not the final step in graduate education. When students with master's degrees decide to continue their education and are accepted to Ph.D. programs, they often find that their credits do not transfer and that they will be required to re-do large portions of their master's degree at their new Ph.D.-granting institution. Here we discuss the need for gathering more data to understand both the different pathways to a Ph.D. and the students that choose each route. We also discuss some of the challenges faced by students that earn a master's degree before beginning a Ph.D. program. As students in the physical sciences that complete a master's and a Ph.D. at different schools take over 2 years longer to reach a Ph.D. than students that get both degrees from the same school, we suggest steps that can be taken to help these students succeed in a timely manner.

S. Saracino (1 and 2), N. Bastian (1), V. Kozhurina-Platais (3), I. Cabrera-Ziri (4), E. Dalessandro (2), N. Kacharov (5), C. Lardo (6), S. S. Larsen (7), A. Mucciarelli (2 and 8), I. Platais (9), M. Salaris (1) ((1) LJMU, (2) INAF-OAS Bologna, (3) STScI, (4) Harward-CFA, (5) MPIA-Heidelberg, (6) EPFL, (7) Radboud University, (8) DIFA-UNIBO, (9) Johns Hopkins University-Baltimore)

5 pages, 4 figures. Accepted for publication in MNRAS Letters

The discovery of star-to-star abundance variations (a.k.a. multiple populations - MPs) within globular clusters (GCs), which are generally not found in the field or in lower mass open clusters, has led to a search for the unique property of GCs that allow them to host this phenomenon. Recent studies have shown that MPs are not limited to the ancient GCs but are also found in massive clusters with ages down to (at least) 2 Gyr. This finding is important for understanding the physics of the MP phenomenon, as these young clusters can provide much stronger constraints (e.g. on potential age spreads within the clusters) than older ones. However, a direct comparison between ancient GCs and intermediate clusters has not yet been possible due to the different filters adopted in their studies. Here we present new HST UV photometry of the 7.5 Gyr, massive SMC cluster, Lindsay 1, in order to compare its pseudo colour-colour diagram to that of Galactic GCs. We find that they are almost identical and conclude that the MPs phenomenon is the same, regardless of cluster age and host galaxy.

S. Martín, J. Martín-Pintado, C. Blanco-Sánchez, V. M. Rivilla, A. Rodríguez-Franco, F. Rico-Villas

18 pages, 7 Figures, Accepted for publication in A&A

In this paper we present the detailed formalism at the core of the Spectral Line Identification and Modelling (SLIM) within the MAdrid Data CUBe Analysis (MADCUBA) package and their main data handling functionalities. These tools have been developed to visualize, analyze and model large spectroscopic data cubes. We present the highly interactive on-the-fly visualization and modelling tools of MADCUBA and SLIM, which includes an stand-alone spectroscopic database. The parameters stored therein are used to solve the full radiative transfer equation under Local Thermodynamic Equilibrium (LTE). SLIM provides tools to generate synthetic LTE model spectra based on input physical parameters of column density, excitation temperature, velocity, line width and source size. SLIM also provides an automatic fitting algorithm to obtain the physical parameters (with their associated errors) better fitting the observations. Synthetic spectra can be overlayed in the data cubes/spectra to easy the task of multi-molecular line identification and modelling.We present the Java-based MADCUBA and its internal module SLIM packages which provide all the necessary tools for manipulation and analysis of spectroscopic data cubes. We describe in detail the spectroscopic fitting equations and make use of this tool to explore the breaking conditions and implicit errors of commonly used approximations in the literature. Easy-to-use tools like MADCUBA allow the users to derive the physical information from spectroscopic data without the need of resourcing to simple approximations. SLIM allows to use the full radiative transfer equation, and to interactively explore the space of physical parameters and associated uncertainties from observational data.

Bruce Grossan, Pawan Kumar, George F. Smoot

19 pages, 4 figures, abstract truncated for arxiv format

There is no consensus on the emission mechanism of $\gamma$-ray bursts (GRBs). A synchrotron model can produce $\gamma$-ray spectra with the empirical Band function form, from a piece-wise two-power-law electron energy distribution (2EPLS). This model predicts that for the same $\gamma$-ray spectrum, optical emission can be very different in $f_{\nu}$ log slope, and in flux relative to $\gamma$-rays,depending on model parameter values. The model only allows a small set of $f_{\nu}$ log slopes in the optical -thereby allowing a clear path to verification or falsification. Measurements of prompt GRB emission in the optical thus far give no useful information about the spectral shape within the band, and therefore cannot be used to evaluate such predictions. We describe an experiment that responds to GRB alerts with a fast-slewing telescope, with 3+ simultaneous, high-time resolution cameras. Three channels measure two slopes in order to evaluate the model. We propose cross-correlation of $\gamma$ and OIR light curves to verify that GRB are single-component dominated, or to quantify additional contributions. Previous CCD measurements have limited-time resolution due to read noise. Electron-multiplied CCDS (EMCCDs) can be used to greatly reduce read noise allowing exposure times of a few hundred ms. Our Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) utilizes a 70 cm telescope that can point in $\le$ 8 s, with 3 optical channels. The NUTTelA-TAO is expected to measure 3-8 GRB/yr, and verify/refute the 2EPLS model with just a few bright GRBs. A space-based experiment with an IR channel would make improved measurements of the self-absorption frequency and physical conditions within the GRB jet. Additional science includes detection of dust evaporation due to GRBs, a tool to study progenitor environment dust.

B. Mennesson, V. Bailey, J. Kasdin, J. Trauger, O. Absil, R. Akeson, L. Armus, J. L. Baudino, P. Baudoz, A. Bellini, D. Bennett, B. Berriman, A. Boccaletti, S. Calchi-Novati, K. Carpenter, C. Chen, W. Danchi, J. Debes, D. Defrere, S. Ertel, M. Frerking, C. Gelino, J. Girard, T. Groff, S. Kane, G. Helou, J. Kalirai, Q. Kral, J. Krist, J. Kruk, Y. Hasegawa, A. M. Lagrange, S. Laine, M. Langlois, P. Lowrance, A. L. Maire, S. Malhotra, A. Mandell, P. Marshall, M. McElwain, T. Meshkat, R. Millan-Gabet, L. Moustakas, B. Nemati, R. Paladini, M. Postman, L. Pueyo, E. Quintana, S. Ramirez, J. Rhodes, A. J. E. Riggs, M. Rizzo, D. Rouan, R. Soummer, K. Stapelfeldt, C. Stark, M. Turnbull, R. van der Marel, A. Vigan, M. Ygouf, M. Wyatt, F. Zhao, N. Zimmerman

6 pages, 2 figures

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) will be the first high-performance stellar coronagraph using active wavefront control for deep starlight suppression in space, providing unprecedented levels of contrast, spatial resolution, and sensitivity for astronomical observations in the optical. One science case enabled by the CGI will be taking images and(R~50)spectra of faint interplanetary dust structures present in the habitable zone of nearby sunlike stars (~10 pc) and within the snow-line of more distant ones(~20pc), down to dust density levels commensurate with that of the solar system zodiacal cloud. Reaching contrast levels below~10-7 for the first time, CGI will cross an important threshold in debris disks physics, accessing disks with low enough optical depths that their structure is dominated by transport phenomena than collisions. Hence, CGI results will be crucial for determining how exozodiacal dust grains are produced and transported in low-density disks around mature stars. Additionally, CGI will be able to measure the brightness level and constrain the degree of asymmetry of exozodiacal clouds around individual nearby sunlike stars in the optical, at the ~10x solar zodiacal emission level. This information will be extremely valuable for optimizing the observational strategy of possible future exo-Earth direct imaging missions, especially those planning to operate at optical wavelengths, such as Habitable Exoplanet Observatory (HabEx) and the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR).

M. Heida, R.M. Lau, B. Davies, M. Brightman, F. Fürst, B.W. Grefenstette, J.A. Kennea, F. Tramper, D.J. Walton, F.A. Harrison

10 pages, 6 figures, accepted for publication in ApJ Letters

SN2010da/NGC 300 ULX-1 was first detected as a supernova impostor in May 2010 and was recently discovered to be a pulsating ultraluminous X-ray source. In this letter, we present VLT/X-shooter spectra of this source obtained in October 2018, covering the wavelength range 350-2300 nm. The $J$- and $H$-bands clearly show the presence of a red supergiant donor star that is best matched by a MARCS stellar atmosphere with $T_{\rm eff} = 3650 - 3900$ K and $\log(L_{\rm bol}/L_{\odot}) = 4.25\pm0.10$, which yields a stellar radius $R = 310 \pm 70 R_{\odot}$. To fit the full spectrum, two additional components are required: a blue excess that can be fitted either by a hot blackbody (T $\gtrsim 20,000$ K) or a power law (spectral index $\alpha \approx 4$) and is likely due to X-ray emission reprocessed in the outer accretion disk or the donor star; and a red excess that is well fitted by a blackbody with a temperature of $\sim 1100$ K, and is likely due to warm dust in the vicinity of SN2010da. The presence of a red supergiant in this system implies an orbital period of at least 0.8-2.1 years, assuming Roche lobe overflow. Given the large donor-to-compact object mass ratio, orbital modulations of the radial velocity of the red supergiant are likely undetectable. However, the radial velocity amplitude of the neutron star is large enough (up to 40-60 km s$^{-1}$) to potentially be measured in the future, unless the system is viewed at a very unfavorable inclination.

Elie Bouffard, Daryl Haggard, Michael A. Nowak, Joseph Neilsen, Sera Markoff, Frederick K. Baganoff

An unusual object, G2, had its pericenter passage around Sgr A*, the $4\times10^6$ M$_\odot$ supermassive black hole in the Galactic Centre, in Summer 2014. Several research teams have reported evidence that following G2's pericenter encounter the rate of Sgr A*'s bright X-ray flares increased significantly. Our analysis carefully treats varying flux contamination from a nearby magnetic neutron star and is free from complications induced by using data from multiple X-ray observatories with different spatial resolutions. We test the scenario of an increased bright X-ray flaring rate using a massive dataset from the \textit{Chandra X-ray Observatory}, the only X-ray instrument that can spatially distinguish between Sgr A* and the nearby Galactic Centre magnetar throughout the full extended period encompassing G2's encounter with Sgr A*. We use X-ray data from the 3 Ms observations of the \textit{Chandra} \textit{X-ray Visionary Program} (XVP) in 2012 as well as an additional 1.5 Ms of observations up to 2018. We use detected flares to make distributions of flare properties. Using simulations of X-ray flares accounting for important factors such as the different $Chandra$ instrument modes, we test the null hypothesis on Sgr A*'s bright (or any flare category) X-ray flaring rate around different potential change points. In contrast to previous studies, our results are consistent with the null hypothesis; the same model parameters produce distributions consistent with the observed ones around any plausible change point.

Masato Shirasaki, Erwin T. Lau, Daisuke Nagai

21 pages, 12 figures, 4 tables

Upcoming multi-wavelength astronomical surveys will soon discover all massive galaxy clusters and provide unprecedented constraints on cosmology and cluster astrophysics. In this paper, we investigate the constraining power of the multi-band cluster surveys, through a joint analysis of three observables associated with clusters of galaxies, including thermal Sunyaev-Zel'dovich (tSZ) effect in cosmic microwave background (CMB), X-ray emission of ionized gas, and gravitational weak lensing effect of background galaxies by the cluster's gravitational potential. We develop a theoretical framework to predict and interpret two-point correlation statistics among the three observables using a semi-analytic model of intracluster medium (ICM) and halo-based approach. In this work, we show that the auto- and cross-angular power spectra in tSZ, X-ray and lensing statistics from upcoming missions (eROSITA, CMB-S4, and LSST) can help break the degeneracy between cosmology and ICM physics. These correlation statistics are less sensitive to selection biases, and are able to probe ICM physics in distant, faint and small clusters that are otherwise difficult to be detected individually. We show that the correlation statistics are able to provide cosmological constraints complementary to the conventional cluster abundance measurements, while constraining cluster astrophysics at the same time. Our results indicate that the correlation statistics can significantly enhance the scientific returns of upcoming multi-wavelength cluster surveys.

Jihyun Kim, Dongsu Ryu, Soonyoung Roh, Jihoon Ha, Hyesung Kang

8 pages, 2 figures, Proceedings of the 36th International Cosmic Ray Conference (ICRC 2019), July 24th - August 1st, Madison, WI, USA

A high concentration of ultra-high-energy cosmic ray (UHECR) events, called a hotspot, was reported by the Telescope Array (TA) experiment, but its origin still remains unsolved. One of the obstacles is that there is no astronomical object, which could be the source, behind the TA hotpot. In an effort to understand the origin of the TA hotspot, we suggested a model based on the magnetized cosmic web structure. The UHECRs were produced from sources in the Virgo cluster and were initially confined by cluster magnetic fields for a certain period. Next, some of them preferentially escaped to and propagated along filaments. Eventually, they were scattered by filament magnetic fields, and come to us. To examine the model, we followed the propagation trajectories of UHE protons in a simulated universe with clusters, filaments, and voids, by employing a number of models for cosmic magnetic fields. In this study, we present some of the initial results, such as the ratio between the particles directly escaping from the clusters to the voids and particles escaping from the clusters to the filaments. We also discuss the feasibility of our model for the origin of the hotspot by examining the trajectories of the UHE protons.

Troy A. Porter, Gudlaugur Johannesson, Igor V. Moskalenko

20 pages, 12 figures, 2 movies. ApJ submitted. Movies and configuration files will be available at the GALPROP website: this https URL

Cosmic rays (CRs) in the Galaxy are an important dynamical component of the interstellar medium (ISM) that interact with the other major components (interstellar magnetic and radiation fields, and gas) to produce broadband interstellar emissions that span the electromagnetic spectrum. The standard modelling of CR propagation and production of the associated emissions is based on a steady-state assumption, where the CR source spatial density is described using a smoothly varying function of position that does not evolve with time. While this is a convenient approximation, reality is otherwise where primary CRs are produced in and about highly localised regions, e.g., supernova remnants, which have finite lifetimes. In this paper we use the latest version of the GALPROP CR propagation code to model time-dependent CR injection and propagation through the ISM from a realistic three-dimensional discretised CR source density distribution, together with full three-dimensional models for the other major ISM components, and make predictions of the associated broadband non-thermal emissions. We compare the predictions for the discretised and equivalent steady-state model, finding that the former predicts novel features in the broadband non-thermal emissions that are absent for the steady-state case. Some of features predicted by the discretised model may be observable in all-sky observations made by WMAP and Planck, the recently launched eROSITA, the Fermi-LAT, and ground-based observations by HESS, HAWC, and the forthcoming CTA. The non-thermal emissions predicted by the discretised model may also provide explanations of puzzling anomalies in high-energy gamma ray data, such as the Fermi-LAT north/south asymmetry and residuals like the so-called "Fermi bubbles".

Yoshiyuki Inoue, Dmitry Khangulyan, Akihiro Doi

5 pages, 2 figures

Spectral excess in the millimeter spectrum of NGC 1068 has been recently reported. We find that this spectral excess can be well reproduced by coronal synchrotron emission model. This is the third example showing the signature of coronal synchrotron emission. The coronal size and magnetic field strength is inferred as $R_c=57 r_s$ and $B=14$ G, respectively, where $r_s$ is the Schwartzschild radius, and the spectral index of non-thermal electrons is $p=2.7$. The derived magnetic field and coronal size indicate that magnetic activity can not sustain the corona X-ray emission. This indicates that other heating scenarios such as advection or shock heating are required. Considering particle acceleration in the corona with the parameters determined from the millimeter spectrum, we find that the coronal high energy neutrino emission can explain the tentatively reported IceCube neutrino flux above several TeV from NGC 1068, while it is hard to explain the observed GeV gamma-ray photons due to internal gamma-ray attenuation. Future MeV gamma-ray observations such as GRAMS and AMEGO will be able to verify our scenario.

Marta Spinelli, Anna Zoldan, Gabriella De Lucia, Lizhi Xie, Matteo Viel

21 pages, 20 figures, comments welcome

We present a comprehensive analysis of atomic hydrogen (HI) properties using a semi-analytical model of galaxy formation and N-body simulations covering a large cosmological volume at high resolution. We examine the HI mass function and the HI density, characterizing both their redshift evolution and their dependence on hosting halo mass. We analyze the HI content of dark matter haloes in the local Universe and up to redshift $z=5$, discussing the contribution of different galaxy properties. We find that different assembly history plays a crucial role in the scatter of this relation. We propose new fitting functions useful for constructing mock HI maps with HOD techniques. We investigate the HI clustering properties relevant for future $21$~cm Intensity Mapping (IM) experiments, including the HI bias and the shot noise level. The HI bias increases with redshift and it is roughly flat on the largest scales probed. The scale dependency is found at progressively larger scales with increasing redshift, apart from a dip feature at $z=0$. The shot-noise values are consistent with the ones inferred by independent studies, confirming that shot-noise will not be a limiting factor for IM experiments. We detail the contribution from various galaxy properties on the HI power spectrum and their relation to the halo bias. We find that HI poor satellite galaxies play an important role at the scales of the 1-halo term. Finally, we present the $21$~cm signal in redshift space, a fundamental prediction to be tested against data from future radio telescopes such as SKA.

Johanna Jurcsik

18 pages, 12 figures Accepted for publication in MNRAS

Blazhko stars from the extended $BVI_{\mathrm C}$ time series of RRab stars in the globular cluster, M3, are analysed. This is the largest sample of Blazhko stars with full details of their Blazhko properties in a homogeneous stellar system. Blazhko periods and light-curve solutions are determined/estimated for 83 fundamental-mode variables. The lack of phase modulation in Oosterhoff-type~II stars and the diminishing relative strength of the modulation in long-period Oosterhoff-type~I stars are the regular tendencies found between the pulsation and modulation properties of Blazko stars. Similarly to previous results, no modulation of the longest-period stars is detected. The onset of the modulation in a previously regular RRab star, and the similar distribution of modulated and non-modulated stars imply that the modulation is a temporal property of RRL stars, which may occur at any time in any RRab star except the coolest ones. Comparing the modulation periods in M3 and in other samples of Blazhko stars, the mean log$(P_{\mathrm {mod}})$ value is found to depend on the metallicity of the system. The separation of the temperature- and radius-change induced variations supports our previous finding that the photometric radius variation does not show any modulation. The pulsation-averaged mean brightness and temperature of Blazhko stars are found to be larger in the large-amplitude phase of the modulation than in the small-amplitude phase. The larger the amplitude of the modulation, the larger changes of the mean parameters are detected.

Agnieszka Leszczyńska, Matthias Plum (for the IceCube Collaboration)

Presented at the 36th International Cosmic Ray Conference (ICRC 2019). See arXiv:1907.11699 for all IceCube contributions

The IceCube Neutrino Observatory at the South Pole is a multi-component particle detector consisting of the IceTop surface array and the deep in-ice IceCube array. The foreseen enhancement of the surface instrumentation will consist of plastic scintillator panels read out by silicon photomultipliers. This additional detector component will calibrate the effect of snow accumulation on the IceTop tanks, improve the measurement of cosmic rays, and enhance the atmospheric background rejection for the high-energy astrophysical neutrino detection. Two scintillator prototype stations were deployed at IceTop in the austral summer of 2017/18 to test the detector design and have started taking data. In order to understand the properties of the scintillator panel response a detailed Geant4 simulation of a single detector, including the photon propagation and simulated SiPM response, is being developed and parameterized. We investigate the capabilities of the IceTop upgrade with an optimized layout of the new detectors and the accuracy of the reconstruction. We will present the details of the simulation and reconstruction studies for the proposed IceTop enhancement and report the capabilities of the combined installation.

Andrew L. Miller, Pia Astone, Sabrina D'Antonio, Sergio Frasca, Giuseppe Intini, Iuri La Rosa, Paola Leaci, Simone Mastrogiovanni, Federico Muciaccia, Andonis Mitidis, Cristiano Palomba, Ornella J. Piccinni, Akshat Singhal, Bernard F. Whiting, Luca Rei

We present a comprehensive study of the effectiveness of Convolution Neural Networks (CNNs) to detect long duration transient gravitational-wave signals lasting $O(hours-days)$ from isolated neutron stars. We determine that CNNs are robust towards signal morphologies that differ from the training set, and they do not require many training injections/data to guarantee good detection efficiency and low false alarm probability. In fact, we only need to train one CNN on signal/noise maps in a single 150 Hz band; afterwards, the CNN can distinguish signals/noise well in any band, though with different efficiencies and false alarm probabilities due to the non-stationary noise in LIGO/Virgo. We demonstrate that we can control the false alarm probability for the CNNs by selecting the optimal threshold on the outputs of the CNN, which appears to be frequency dependent. Finally we compare the detection efficiencies of the networks to a well-established algorithm, the Generalized FrequencyHough (GFH), which maps curves in the time/frequency plane to lines in a plane that relates to the initial frequency/spindown of the source. The networks have similar sensitivities to the GFH but are orders of magnitude faster to run and can detect signals to which the GFH is blind. Using the results of our analysis, we propose strategies to apply CNNs to a real search using LIGO/Virgo data to overcome the obstacles that we would encounter, such as a finite amount of training data. We then use our networks and strategies to run a real search for a remnant of GW170817, making this the first time ever that a machine learning method has been applied to search for a gravitational wave signal from an isolated neutron star.

Frans Snik, Christoph U. Keller, David S. Doelman, Jonas Kühn, C. H. Lucas Patty, H. Jens Hoeijmakers, Vidhya Pallichadath, Daphne M. Stam, Antoine Pommerol, Olivier Poch, Brice-Olivier Demory

We present the design of a point-and-shoot non-imaging full-Stokes spectropolarimeter dedicated to detecting life on Earth from an orbiting platform like the ISS. We specifically aim to map circular polarization in the spectral features of chlorophyll and other biopigments for our planet as a whole. These non-zero circular polarization signatures are caused by homochirality of the molecular and supramolecular configurations of organic matter, and are considered the most unambiguous biomarker. To achieve a fully solid-state snapshot design, we implement a novel spatial modulation that completely separates the circular and linear polarization channels. The polarization modulator consists of a patterned liquid-crystal quarter-wave plate inside the spectrograph slit, which also constitutes the first optical element of the instrument. This configuration eliminates cross-talk between linear and circular polarization, which is crucial because linear polarization signals are generally much stronger than the circular polarization signals. This leads to a quite unorthodox optical concept for the spectrograph, in which the object and the pupil are switched. We discuss the general design requirements and trade-offs of LSDpol (Life Signature Detection polarimeter), a prototype instrument that is currently under development.

Minju M. Lee, Tohru Nagao, Carlos De Breuck, Stefano Carniani, Giovanni Cresci, Bunyo Hatsukade, Ryohei Kawabe, Kotaro Kohno, Roberto Maiolino, Filippo Mannucci, Alessandro Marconi, Kouichiro Nakanishi, Toshiki Saito, Yoichi Tamura, Paulina Troncoso, Hideki Umehata, Min Yun

10 pages, 4 figures, 1 table, accepted for publication in the ApJL

We report the first detection obtained with ALMA of the [N II] 122$\mu$m line emission from a galaxy group BRI 1202-0725 at $z=4.69$ consisting of a QSO and a submilimeter-bright galaxy (SMG). Combining with a detection of [N II] 205$\mu$m line in both galaxies, we constrain the electron densities of the ionized gas based on the line ratio of [NII]122/205. The derived electron densities are $26^{+12}_{-11}$ and $134^{+50}_{-39}$ cm$^{-3}$ for the SMG and the QSO, respectively. The electron density of the SMG is similar to that of the Galactic Plane and to the average of the local spirals. Higher electron densities by up to a factor of three could, however, be possible for systematic uncertainties of the line flux estimates. The electron density of the QSO is comparable to high-$z$ star-forming galaxies at $z=1.5-2.3$, obtained using rest-frame optical lines and with the lower limits suggested from stacking analysis on lensed starbursts at $z=1-3.6$ using the same tracer of [NII]. Our results suggest a large scatter of electron densities in global scale at fixed star formation rates for extreme starbursts. The success of the [N II] 122$\mu$m and 205$\mu$m detections at $z=4.69$ demonstrates the power of future systematic surveys of extreme starbursts at $z>4$ for probing the ISM conditions and the effects on surrounding environments.

H. Miyamoto, M. Battisti, A. Belov, M. E. Bertaina, F. Bisconti, R. Bonino, S. Blin-Bondil, F. Cafagna, G. Cambiè, F. Capel, R. Caruso, M. Casolino, A. Cellino, I. Churilo, G. Contino, G. Cotto, A. Djakonow, T. Ebisuzaki, F. Fausti, F. Fenu, C. Fornaro, A. Franceschi, C. Fuglesang, D. Gardiol, P. Gorodetzky, F. Kajino, P. Klimov, L. Marcelli, W. Marszał, M. Mignone, A. Murashov, T. Napolitano, G. Osteria, M. Panasyuk, E. Parizot, A. Poroshin, P. Picozza, L. W. Piotrowski, Z. Plebaniak, G. Prévôt, M. Przybylak, E. Reali, M. Ricci, N. Sakaki, K. Shinozaki, G. Suino, J. Szabelski, Y. Takizawa, M. Traïche, S. Turriziani (for the JEM-EUSO Collaboration)

8 pages, 6 figures, ICRC2019

The TurLab facility is a laboratory, equipped with a 5 m diameter and 1 m depth rotating tank, located in the Physics Department of the University of Turin. Originally, it was mainly built to study systems of different scales where rotation plays a key role in the fluid behavior such as in atmospheric and oceanic flows. In the past few years the TurLab facility has been used to perform experiments related to the observation of Extreme Energy Cosmic Rays (EECRs) from space using the fluorescence technique. For example, in the case of the JEM-EUSO mission, where the diffuse night brightness and artificial light sources can vary significantly in time and space inside the Field of View of the telescope. The Focal Surface of Mini-EUSO Engineering Model (Mini-EUSO EM) with the level 1 (L1) and 2 (L2) trigger logics implemented in the Photo-Detector Module (PDM) has been tested at TurLab. Tests related to the possibility of using an EUSO-like detector for other type of applications such as Space Debris (SD) monitoring and imaging detector have also been pursued. The tests and results obtained within the EUSO@TurLab Project on these different topics are presented.

Tariq Shahbaz (Instituto de Astrofísica de Canarias)

26 pages, 16 figures; to be published in Astrophysics and Space Science Library 460, Astronomical Polarisation from the Infrared to Gamma Rays, Editors: Mignani, R., Shearer, A., S{\l}owikowska, A., Zane, S

Polarimetry provides key physical information on the properties of interacting binary systems, sometimes difficult to obtain by any other type of observation. Indeed, radiation processes such as scattering by free electrons in the hot plasma above accretion discs, cyclotron emission by mildly relativistic electrons in the accretion shocks on the surface of highly magnetic white dwarfs and the optically thin synchrotron emission from jets can be observed. In this review, I will illustrate how optical/near-infrared polarimetry allows one to estimate magnetic field strengths and map the accretion zones in magnetic Cataclysmic Variables as well as determine the location and nature of jets and ejection events in X-ray binaries.

N.V. Gusinskaia, T.D. Russell, J.W.T. Hessels, S. Bogdanov, N. Degenaar, A.T. Deller, J. van den Eijnden, A.D. Jaodand, J.C.A. Miller-Jones, R. Wijnands

12 pages, 3 figures, 2 tables, submitted to MNRAS

IGR J17591$-$2342 is a new accreting millisecond X-ray pulsar (AMXP) that was recently discovered in outburst in 2018. Early observations revealed that the source's radio emission is brighter than that of any other known neutron star low-mass X-ray binary (NS-LMXB) at comparable X-ray luminosity, and assuming its likely $\gtrsim 6$ kpc distance. It is comparably radio bright to black hole LMXBs at similar X-ray luminosities. In this work, we present the results of our extensive radio and X-ray monitoring campaign of the 2018 outburst of IGR J17591$-$2342. In total we collected 10 quasi-simultaneous radio (VLA, ATCA) and X-ray (Swift-XRT) observations, which make IGR J17591$-$2342 one of the best-sampled NS-LMXBs. We use these to fit a power-law correlation index $\beta = 0.37^{+0.42}_{-0.40}$ between observed radio and X-ray luminosities ( $L_\mathrm{R}\propto L_\mathrm{X}^{\beta}$). However, our monitoring revealed a large scatter in IGR J17591$-$2342's radio luminosity (at a similar X-ray luminosity, $L_\mathrm{X} \sim 10^{36}$ erg s$^{-1}$, and spectral state), with $L_\mathrm{R} \sim 4 \times 10^{29}$ erg s$^{-1}$ during the first three reported observations, and up to a factor of 4 lower $L_\mathrm{R}$ during later radio observations. Nonetheless, the average radio luminosity of IGR J17591$-$2342 is still one of the highest among NS-LMXBs, and we discuss possible reasons for the wide range of radio luminosities observed in such systems during outburst. We found no evidence for radio pulsations from IGR J17591$-$2342 in our Green Bank Telescope observations performed shortly after the source returned to quiescence. Nonetheless, we cannot rule out that IGR J17591$-$2342 becomes a radio millisecond pulsar during quiescence.

Donatella Romano, Francesco Calura, Annibale D'Ercole, C. Gareth Few

16 pages, 16 figures, accepted for publication in Astronomy and Astrophysics

The faintest Local Group galaxies found lurking in and around the Milky Way halo provide a unique test bed for theories of structure formation and evolution on small scales. Deep Subaru and Hubble Space Telescope photometry demonstrates that their stellar populations are old, and that the star formation activity did not last longer than 2 Gyr in these systems. A few mechanisms that may lead to such a rapid quenching have been investigated by means of hydrodynamic simulations, without providing any final assessment so far. This is the first in a series of papers aimed at analysing the roles of stellar feedback, ram pressure stripping, host-satellite tidal interactions and reionization in cleaning the lowest-mass Milky Way companions of their cold gas, by using high-resolution, three-dimensional hydrodynamic simulations. We simulate an isolated ultrafaint dwarf galaxy loosely modeled after Bootes I, and examine whether or not stellar feedback alone could drive a substantial fraction of the ambient gas out from the shallow potential well. In contrast to simple analytical estimates, but in agreement with previous hydrodynamical studies, we find that most of the cold gas reservoir is retained. Conversely, a significant fraction of the metal-enriched stellar ejecta crosses the boundaries of the computational box with velocities exceeding the local escape velocity and is, thus, likely lost from the system. Although the total energy output from multiple supernova explosions exceeds the binding energy of the gas, no galactic-scale outflow develops in our simulations and as such, most of the ambient medium remains trapped within the weak potential well of the model galaxy. It seems thus unavoidable that, in order to explain the dearth of gas in ultrafaint dwarf galaxies, we will have to resort to environmental effects. This will be the subject of a forthcoming paper.

Xing Lu, Elisabeth A. C. Mills, Adam Ginsburg, Daniel Walker, Ashley Barnes, Natalie Butterfield, Jonathan Henshaw, Cara Battersby, J. M. Diederik Kruijssen, Steven N. Longmore, Qizhou Zhang, John Bally, Jens Kauffmann, Jürgen Ott, Matthew Rickert, Ke Wang

26 pages, 7 pages, 6 tables. ApJ accepted. The continuum images are publicly available at this https URL . A pdf file with finer image resolutions is available at this https URL

We present new observations of C-band continuum emission and masers to assess high-mass ($>$8 $M_\odot$) star formation at early evolutionary phases in the inner 200 pc of the Central Molecular Zone (CMZ) of the Galaxy. The continuum observation is complete to free-free emission from stars above 10-11 $M_\odot$ in 91% of the covered area. We identify 104 compact sources in the continuum emission, among which five are confirmed ultracompact H II regions, 12 are candidates of ultra-compact H II regions, and the remaining 87 sources are mostly massive stars in clusters, field stars, evolved stars, pulsars, extragalactic sources, or of unknown nature that is to be investigated. We detect class II CH$_3$OH masers at 23 positions, among which six are new detections. We confirm six known H$_2$CO masers in two high-mass star forming regions, and detect two new H$_2$CO masers toward the Sgr C cloud, making it the ninth region in the Galaxy that contains masers of this type. In spite of these detections, we find that current high-mass star formation in the inner CMZ is only taking place in seven isolated clouds. The results suggest that star formation at early evolutionary phases in the CMZ is about 10 times less efficient than expected by the dense gas star formation relation, which is in line with previous studies that focus on more evolved phases of star formation. This means that if there will be any impending, next burst of star formation in the CMZ, it has not yet begun.

Adam Malyali, Arne Rau, Kirpal Nandra

12 pages, 4 figures. Accepted for publication in MNRAS

White dwarf-black hole tidal disruption events (herein WTDEs) present an opportunity to probe the quiescent intermediate mass black hole population in the universe. We run an extensive set of Monte-Carlo based simulations to explore SRG/eROSITA's detection sensitivity to WTDEs as a function of black hole mass, redshift and time offset between event flaring and it first being observed. A novel estimate of WTDE rate densities from globular clusters and dwarf galaxies is also presented. We combine this with estimated detection sensitivities to infer the rate of eROSITA detecting these events. Depending on the estimate of the intrinsic rate of WTDEs, we anticipate that eROSITA may detect $\sim 3$ events over its 4 year all-sky survey. eROSITA will be most sensitive to systems with black hole masses above $10^4M_{\odot}$, and is most likely to catch these within 5 days of flaring.

The presence of the dark energy allows both the acceleration and the expansion of the universe. In the case of a constant equation of state for dark energy we derived an analytical solution for the Hubble radius in terms of the hypergeometric function. An approximate Taylor expansion of order seven is derived for both the constant and the variable equation of state for dark energy. In the case of the Cardassian cosmology we also derived an analytical solution for the Hubble radius in terms of the hypergeometric function. The astronomical samples of the distance modulus for Supernova (SN) of type Ia allows the derivation of the involved cosmological in the case of constant equation of state, variable equation of state and Cardassian cosmology.

Gilles Duvert, Alain Coulais, Mark Schellens

4 pages. Contributed paper at the ADASS XXVII conference, held in Santiago de Chile, Chile, October 2017. Proceedings to be published in ASP Conf. Ser. 522, 641, Ballester, P. et al., Eds., 2019

We report at the ADASS XXVII session the progresses made by GDL, the free clone of the proprietary IDL software. We argue that GDL can replace IDL for everyday use.

A hierarchical Bayesian classifier is trained at pixel scale with spectral data from the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) imagery. Its utility in detecting rare phases is demonstrated with new geologic discoveries near the Mars-2020 rover landing site. Akaganeite is found in sediments on the Jezero crater floor and in fluvial deposits at NE Syrtis. Jarosite and silica are found on the Jezero crater floor while chlorite-smectite and Al phyllosilicates are found in the Jezero crater walls. These detections point to a multi-stage, multi-chemistry history of water in Jezero crater and the surrounding region and provide new information for guiding the Mars-2020 rover's landed exploration. In particular, the akaganeite, silica, and jarosite in the floor deposits suggest either a later episode of salty, Fe-rich waters that post-date Jezero delta or groundwater alteration of portions of the Jezero sedimentary sequence.

Johannes Wicht, Wieland Dietrich, Paula Wulff, Ulrich R. Christensen

28 pages, 6 figures

Recent precise measurements at Jupiter's and Saturn's gravity fields constrain the properties of the zonal flows in the outer envelopes of these planets. A simplified dynamic equation, sometimes called the thermal wind or thermo-gravitational wind equation, establishes a link between zonal flows and the related buoyancy perturbation, which in turn can be exploited to yield the dynamic gravity perturbation. Whether or not the action of the dynamic gravity perturbation needs to be explicitly included in this equation, an effect we call the Dynamic Self Gravity (DSG), has been a matter of intense debate. We show that, under reasonable assumptions, the equation can be solved (semi) analytically. This allows us to quantify the impact of the DSG on each gravity harmonic, practically independent of the zonal flow or the details of the planetary interior model. The impact decreases with growing spherical harmonic degree l. For degrees l=2 to about l=4, the DSG is a first order effect and should be taken into account in any attempt of inverting gravity measurements for zonal flow properties. For degrees of about l=5 to roughly l=10, the relative impact of DSG is about 10% and thus seems worthwhile to include, in particular since this comes at little extra costs with the method presented here. For yet higher degrees, is seems questionable whether gravity measurements or interior models will ever reach the required precision equivalent of the DSG impact of only a few percent of less.

Alexander Kappes, Manel Perucho, Matthias Kadler, Paul Ray Burd, Laura Vega-García, Marcus Brüggen

9 pages, 9 figures, 2 tables, recommended for publication in section 4. Extragalactic astronomy of Astronomy and Astrophysics, additional observation images can be found at: this https URL

Our goal is to study the termination of an AGN jet in the young universe and to deduce physical parameters of the jet and the intergalactic medium. We use LOFAR to image the long-wavelength radio emission of the high-redshift blazar S5 0836+710 on arcsecond scales between 120 MHz and 160 MHz. The LOFAR image shows a compact unresolved core and a resolved emission region about 1.5 arcsec to the southwest of the radio core. This structure is in general agreement with previous higher-frequency radio observations with MERLIN and the VLA. The southern component shows a moderately steep spectrum with a spectral index of about $\gtrsim -1$ while the spectral index of the core is flat to slightly inverted. In addition, we detect for the first time a resolved steep-spectrum halo with a spectral index of about $-1$ surrounding the core. The arcsecond-scale radio structure of S5 0836+710 can be understood as an FR II-like radio galaxy observed at a small viewing angle. The southern component can be interpreted as the region of the approaching jet's terminal hotspot and the halo-like diffuse component near the core can be interpreted as the counter-hotspot region. From the differential Doppler boosting of both features, we can derive the hotspot advance speed to $(0.01-0.036)$ c. At a constant advance speed, the derived age of the source would exceed the total lifetime of such a powerful FR II-like radio galaxy substantially. Thus, the hotspot advance speed must have been higher in the past in agreement with a scenario in which the originally highly relativistic jet has lost collimation due to the growth of instabilities and has transformed into an only mildly relativistic flow. Our data suggest that the density of the intergalactic medium around this distant ($z=2.22$) AGN could be substantially higher than the values typically found in less distant FR II radio galaxies.

Lauren M. Weiss, Eric Agol, Daniel C. Fabrycky, Sean M. Mills, Andrew W. Howard, Howard Isaacson, Erik A. Petigura, Benjamin J. Fulton, Lea Hirsch, Evan Sinukoff

24 pages, submitted to AJ

We present the discovery of Kepler-88 d ($P_d = 1414^{+27}_{-23}$ days, $M$sin$i_d = 959\pm57\,M_\oplus$, $e_d = 0.432\pm0.048$) based on six years of radial velocity (RV) follow-up from the W. M. Keck Observatory HIRES spectrograph. Kepler-88 has two previously identified planets: Kepler-88 b (KOI-142.01) transits in the NASA Kepler photometry and has very large transit timing variations. Nesvorny et al. (2013) perfomed a dynamical analysis of the TTVs to uniquely identify the orbital period and mass of the perturbing planet (Kepler-88 c), which was later was confirmed with RVs from the Observatoire Haute-Provence (OHP, Barros2014). To fully explore the architecture of this system, we performed photodynamical modeling on the Kepler photometry combined with the RVs from Keck and OHP and stellar parameters from spectroscopy and Gaia. Planet d is not detectable in the photometry, and long-baseline RVs are needed to ascertain its presence. However, the orbital parameters and masses of interacting planets b and c are improved by an order of magnitude with respect to the RV-only solution when the photometry is included: $P_b =10.91647\pm0.00014$ days, $M_b=9.5\pm 1.2\,M_\oplus$, $P_c=22.2649\pm0.0007$ days, and $M_c=214.2\pm5.2\,M_\oplus$. The photodynamical solution also finds that planets b and c have low eccentricites, are apsidally anti-aligned, and have conjunctions on the same hemisphere of the star. Continued RV follow-up of systems with small planets will improve our understanding of the link between inner planetary system architectures and giant planets.

M. V. Popov, R. Walder, D. Folini, T. Goffrey, I. Baraffe, T. Constantino, C. Geroux, J. Pratt, M. Viallet

12 pages, 8 figures, accepted 30/08/2019 for publication by Astronomy & Astrophysics

Characterizing stellar convection in multiple dimensions is a topic at the forefront of stellar astrophysics. Numerical simulations are an essential tool for this task. We present an extension of the existing numerical tool-kit A-MaZe that enables such simulations of stratified flows in a gravitational field. The finite-volume based, cell-centered, and time-explicit hydrodynamics solver of A-MaZe was extended such that the scheme is now well-balanced in both momentum and energy. The algorithm maintains an initially static balance between gravity and pressure to machine precision. Quasi-stationary convection in slab-geometry preserves gas energy (internal plus kinetic) on average despite strong local up- and down-drafts. By contrast, a more standard numerical scheme is demonstrated to result in substantial gains of energy within a short time on purely numerical grounds. The test is further used to point out the role of dimensionality, viscosity, and Rayleigh number for compressible convection. Applications to a young sun in 2D and 3D, covering a part of the inner radiative zone as well as the outer convective zone, demonstrate that the scheme meets its initial design goal. Comparison with results obtained for a physically identical setup with a time-implicit code show qualitative agreement.

F. Nicastro (1), J. Kaastra (2, 3), C. Argiroffi (4), E. Behar (5), S. Bianchi (6), F. Bocchino (7), S. Borgani (8), G Branduardi-Raymont (9), J. Bregman (10), E. Churazov (11, 12), M. Diaz-Trigo (13), C. Done (14), J. Drake (15), T. Fang (16), N. Grosso (17, 18), A. Luminari (19, 1), M. Mehdipour (2), F. Paerels (20), E. Piconcelli (1), C. Pinto (21), D. Porquet (17, 18), J. Reeves (22), J. Schaye (23), S. Sciortino (7), R. Smith (15), D. Spiga (24), R. Tomaru (25), F. Tombesi (19), N. Wijers (23), L. Zappacosta (1) ((1) INAF - Osservatorio Astronomico di Roma, Italy, (2) SRON, The Netherlands, (3) Leiden University, The Netherlands, (4) University of Palermo, Italy, (5) Technion, Israel, (6) Universita' degli Studi Roma Tre, Italy, (7) INAF-OAPA, Italy, (8) University of Trieste, Italy, (9) MSSL, UK, (10) University of Michigan, USA, (11) MPA, Germany, (12) IKI, Russia, (13) ESO, Germany, (14) University of Durham, UK, (15) SAO - CfA, USA, (16) Xiamen University, China, (17) Aix Marseille University, France, (18) CNRS, CNES, LAM, France, (19) University of Rome Tor-Vergata, Italy, (20) Columbia University, USA, (21) ESA, The Netherlands, (22) University of Maryland, USA, (23) Leiden Observatory, The Netherlands, (24) Stanford University - SLAC-LCLS, USA, (25) University of Tokyo, Japan)

White-Paper submitted in response to the "Voyage-2050" ESA call: cover page + 20 page text (including 16 figures) + 5 page references + list of team-members. Additional supporting authors are listed in the acknowledgment section at page 20 of the paper

Metals form an essential part of the Universe at all scales. Without metals we would not exist, and the Cosmos would look completely different. Metals are primarily born through nuclear processes in stars. They leave their cradles through winds or explosions, and then start their journey through space. This can lead them in and out of astronomical objects on all scales, ranging from comets, planets, stars, entire galaxies, groups and clusters of galaxies to the largest structures of the Universe. Their wanderings are fundamental in determining how these objects, and the entire universe, evolve. In addition, their bare presence can be used to trace what these structures look like. The scope of this paper is to highlight the most important open astrophysical problems that will be central in the next decades and for which a deep understanding of the Universe-wandering metals, their physical and kinematical states and their chemical composition represents the only viable solution. The majority of these studies can only be efficiently performed through High Resolution Spectroscopy in the soft X-ray band.

James Binney (Oxford University)

8 page text of invited review at IAU Symposium 353 `Galactic dynamics in the era of large surveys'

Dynamical models will be key to exploitation of the incoming flood data for our Galaxy. Modelling techniques are reviewed with an emphasis on f(J) modelling.

Francisco Nogueras-Lara, Rainer Schödel, Francisco Najarro, Aurelia Teresa Gallego-Calvente, Eulalia Gallego-Cano, Banafsheh Shahzamanian, Nadine Neumayer

Accepted for publication in A&A. 5 pages, 5 figures

Due to the extreme extinction towards the Galactic centre ($A_{V} \sim 30$ mag), its stellar population is mainly studied in the near-infrared (NIR) regime. Therefore, a proper analysis of the NIR extinction curve is necessary to fully characterise the stellar structure and population of the inner part of the galaxy. We studied the dependence of the extinction index ($\alpha_\lambda$) in the NIR on the line of sight, wavelength, and extinction. We used the GALACTICNUCLEUS imaging survey, a high angular resolution catalogue ($0.2''$) for the inner part of the Galaxy in $JHK_s$, and studied the spatial variation in the extinction index. We also applied two independent methods based on red clump stars to compute the extinction index between different bands and its variation with wavelength. We did not detect any significant line-of-sight or extinction variation in $\alpha$ within the studied region in the nuclear stellar disc. The extinction index between $JH$ and $HK_s$ differs by $0.19 \pm 0.05$. We obtained mean values for the extinction indices $\alpha_{JH} = 2.43\pm0.03$ and $\alpha_{HK_s} = 2.23\pm0.03$. The dependence of the extinction index on the wavelength could explain the differences obtained for $\alpha_\lambda$ in the literature since it was assumed constant for the NIR regime.

Benjamin Bose, Joyce Byun, Fabien Lacasa, Azadeh Moradinezhad Dizgah, Lucas Lombriser

36 pages, 13 figures, 2 tables

Future large-scale structure surveys will measure three-point correlations with high statistical significance. This will offer significant improvements on our understanding of gravity, provided we can model these statistics accurately. Here we assess the performance of various theoretical modelling schemes for the matter bispectrum, including perturbative and halo-model based approaches as well as fitting formulae, which we compare to measurements from N-body simulations. We conduct this analysis for general relativity and two alternative theories, f(R) gravity and the DGP braneworld model. The comparison is performed into the highly non-linear regime of structure formation, up to $k = 4h/{\rm Mpc}$. We furthermore compute the lensing convergence bispectrum from these theoretical approaches. We find that a halo-model corrected fitting formula achieves the best overall performance. Despite this, we also find that all current modelling prescriptions in modified gravity, in particular for theories with scale-dependent linear growth, fail to attain sufficient accuracy for suitability to lensing in the context of Stage IV surveys such as \emph{Euclid}

We use state of the art hydrodyamical simulations from the Sherwood, EAGLE and Illustris projects to examine the signature of $M_{\rm z=0}\simeq 10^{14}M_{\odot}$ protoclusters observed in Ly-$\alpha$ absorption at $z\simeq 2.4$. We find there is a weak correlation between the mass overdensity, $\delta_{\rm m}$, and the Ly-$\alpha$ effective optical depth relative to the mean, $\delta_{\tau_\textrm{eff}}$, averaged over $15~h^{-1}\rm\,cMpc$ scales, although scatter in the $\delta_{\rm m}$--$\delta_{\tau_\textrm{eff}}$ plane means it is not possible to uniquely identify large scale overdensities with strong Ly-$\alpha$ absorption. Although all protoclusters are associated with large scale mass overdensities, most sight lines through protoclusters in a $\sim 10^{6}$ $\rm cMpc^{3}$ volume probe the low column density Ly-$\alpha$ forest. A small subset of sight lines that pass through protoclusters exhibit coherent, strong Ly-$\alpha$ absorption on $15h^{-1}\rm\,cMpc$ scales, although these correspond to a wide range in mass overdensity. Assuming perfect removal of contamination by Ly-$\alpha$ absorbers with damping wings, more than half of the remaining sight lines with $\delta_{\tau_{\rm eff}}>3.5$ trace protoclusters. It is furthermore possible to identify a model dependent $\delta_{\tau_{\rm eff}}$ threshold that selects only protoclusters. However, such regions are rare: excluding absorption caused by damped systems, less than 0.1 per cent of sight lines that pass through a protocluster have $\delta_{\tau_{\rm eff}}>3.5$, meaning that any protocluster sample selected in this manner will also be highly incomplete. On the other hand, coherent regions of Ly-$\alpha$ absorption also provide a promising route for identifying and studying filamentary environments at high redshift.

M. E. Shultz, G. A. Wade, Th. Rivinius, E. Alecian, C. Neiner, V. Petit, S. Owocki, A. ud-Doula, O. Kochukhov, D. Bohlender, Z. Keszthelyi, the MiMeS, BinaMIcS Collaborations

34 pages, 21 figures, 5 tables, accepted for publication in MNRAS

Magnetic confinement of stellar winds leads to the formation of magnetospheres, which can be sculpted into Centrifugal Magnetospheres (CMs) by rotational support of the corotating plasma. The conditions required for the CMs of magnetic early B-type stars to yield detectable emission in H$\alpha$ -- the principal diagnostic of these structures -- are poorly constrained. A key reason is that no detailed study of the magnetic and rotational evolution of this population has yet been performed. Using newly determined rotational periods, modern magnetic measurements, and atmospheric parameters determined via spectroscopic modelling, we have derived fundamental parameters, dipolar oblique rotator models, and magnetospheric parameters for 56 early B-type stars. Comparison to magnetic A- and O-type stars shows that the range of surface magnetic field strength is essentially constant with stellar mass, but that the unsigned surface magnetic flux increases with mass. Both the surface magnetic dipole strength and the total magnetic flux decrease with stellar age, with the rate of flux decay apparently increasing with stellar mass. We find tentative evidence that multipolar magnetic fields may decay more rapidly than dipoles. Rotational periods increase with stellar age, as expected for a magnetic braking scenario. Without exception, all stars with H$\alpha$ emission originating in a CM are 1) rapid rotators, 2) strongly magnetic, and 3) young, with the latter property consistent with the observation that magnetic fields and rotation both decrease over time.

P.S. Athiray, Amy R. Winebarger, Will T. Barnes, Stephen J. Bradshaw, Sabrina Savage, Harry P. Warren, Ken Kobayashi, Patrick Champey, Leon Golub, Lindsay Glesener

Accepted for publication in ApJ

The relative amount of high temperature plasma has been found to be a useful diagnostic to determine the frequency of coronal heating on sub-resolution structures. When the loops are infrequently heated, a broad emission measure (EM) over a wider range of temperatures is expected. A narrower EM is expected for high frequency heating where the loops are closer to equilibrium. The soft X-ray spectrum contains many spectral lines that provide high temperature diagnostics, including lines from Fe XVII-XIX. This region of the solar spectrum will be observed by the Marshall Grazing Incidence Spectrometer (MaGIXS) in 2020. In this paper, we derive the expected spectral lines intensity in MaGIXS to varying amounts of high temperature plasma to demonstrate that a simple line ratio of these provides a powerful diagnostic to determine the heating frequency. Similarly, we examine ratios of AIA channel intensities, filter ratios from a XRT, and energy bands from the FOXSI sounding rocket to determine their sensitivity to this parameter. We find that both FOXSI and MaGIXS provide good diagnostic capability for high-temperature plasma. We then compare the predicted line ratios to the output of a numerical model and confirm the MaGIXS ratios provide an excellent diagnostic for heating frequency.

Ippocratis D. Saltas, Ilídio Lopes

5 pages + references, 4 figures. Version published in Physical Review Letters

We propose helioseismology as a new, precision probe of fifth forces at astrophysical scales, and apply it on the most general scalar-tensor theories for dark energy, known as Degenerate Higher-Order Scalar-Tensor theories (DHOST). We explain how the effect of the fifth force on the solar interior leaves an observable imprint on the acoustic oscillations, and under certain assumptions we numerically compute the non-radial pulsation eigenfrequencies within modified gravity. We illustrate its constraining power by showing that helioseismic observations have the potential to improve constraints on the strength of the fifth force by more than $2$ orders of magnitude, as $-1.8 \cdot 10^{-3} \leq Y \leq 1.2 \cdot 10^{-3}$ (at $2\sigma$). This in turn would suggest constraints of similar order for the theory's free functions around a cosmological background ($\alpha_{\text{H}}, \beta_{1}$).

Joan Sola, Adria Gomez-Valent, Javier de Cruz Perez, Cristian Moreno-Pulido

7 pages, 1 Table, 2 Figures

We analyze Brans-Dicke gravity with a cosmological constant, $\Lambda$, and cold dark matter (BD-$\Lambda$CDM for short) in the light of the latest cosmological observations on distant supernovae, Hubble rate measurements at different redshifts, baryonic acoustic oscillations, large scale structure formation data, gravitational weak-lensing and the cosmic microwave background under full Planck 2015 CMB likelihood. Our analysis includes both the background and perturbations equations. We find that BD-$\Lambda$CDM is observationally favored as compared to the concordance $\Lambda$CDM model, which is traditionally defined within General Relativity (GR). In particular, some well-known persisting tensions of the $\Lambda$CDM with the data, such as the excess in the mass fluctuation amplitude $\sigma_8$ and specially the acute $H_0$-tension with the local measurements, essentially disappear in this context. Furthermore, viewed from the GR standpoint, BD-$\Lambda$CDM cosmology mimics quintessence at $\gtrsim3\sigma$ c.l. near our time.

Matteo Cataneo, J. D. Emberson, Derek Inman, Joachim Harnois-Deraps, Catherine Heymans

7 pages, 3 figures, submitted to MNRAS

We analytically model the non-linear effects induced by massive neutrinos on the total matter power spectrum using the halo model reaction framework of Cataneo et al. 2019. In this approach the halo model is used to determine the relative change to the matter power spectrum caused by new physics beyond the concordance cosmology. Using standard fitting functions for the halo abundance and the halo mass-concentration relation, the total matter power spectrum in the presence of massive neutrinos is predicted to percent-level accuracy, out to $k=10 \, h \, {\rm Mpc}^{-1}$. We find that refining the prescriptions for the halo properties using $N$-body simulations improves the recovered accuracy to better than 1%. This paper serves as another demonstration for how the halo model reaction framework, in combination with a single suite of standard $\Lambda$CDM simulations, can recover percent-level accurate predictions for beyond-$\Lambda$CDM matter power spectra, well into the non-linear regime.

We study the strong first order electroweak phase transition (SFOEWPT) with the $SO(6)/SO(5)$ composite Higgs model, whose scalar sector contains one Higgs doublet and one real singlet. Six benchmark models are built with fermion embeddings in $\textbf{1}$, $\textbf{6}$, and $\textbf{15}$ of $SO(6)$. We show that SFOEWPT cannot be triggered under the minimal Higgs potential hypothesis, which assumes the scalar potential is dominated by the form factors from the lightest composite resonances. To get a SFOEWPT, the contributions from local operators induced by physics above the cutoff scale are needed. We take the $\textbf{6}+\textbf{6}$ model as an example to investigate the gravitational waves prediction and the related collider phenomenology.

There are two strong clues about the quantum structure of spacetime and the gravitational dynamics, which are almost universally ignored in the conventional approaches to quantize gravity. The first clue is that null surfaces exhibit (observer dependent) thermal properties and possess a heat density. This suggests that spacetime, like matter, has microscopic degrees of freedom and its long wavelength limit should be described in thermodynamic language and not in a geometric language. Second clue is related to the existence of the cosmological constant. Its understanding from first principles will require the dynamical principles of the theory to be invariant under the shift $T^a_b \to T^a_b + (constant) \delta^a_b$. This puts strong constraints on the nature of gravitational dynamics and excludes metric tensor as a fundamental dynamical variable. In fact, these two clues are closely related to each other. When the dynamical principles are recast, respecting the symmetry $T^a_b \to T^a_b + (constant) \delta^a_b$, they automatically acquire a thermodynamic interpretation related to the first clue. The first part of this review provides a pedagogical introduction to thermal properties of the horizons, including some novel derivations. The second part describes some aspects of cosmological constant problem and the last part provides a perspective on gravity which takes into account these principles.

Vedran Brdar, Lukas Graf, Alexander J. Helmboldt, Xun-Jie Xu

20 pages, 3 figures

Left-right symmetry at high energy scales is a well-motivated extension of the Standard Model. In this paper we consider a typical minimal scenario in which it gets spontaneously broken by scalar triplets. Such a realization has been scrutinized over the past few decades chiefly in the context of collider studies. In this work we take a complementary approach and investigate whether the model can be probed via the search for a stochastic gravitational wave background induced by the phase transition in which $SU(3)_C \times SU(2)_L \times SU(2)_R \times U(1)_{B-L}$ is broken down to the Standard Model gauge symmetry group. A prerequisite for gravitational wave production in this context is a first-order phase transition, the occurrence of which we find in a significant portion of the parameter space. Although the produced gravitational waves are typically too weak for a discovery at any current or future detector, upon investigating correlations between all relevant terms in the scalar potential, we have identified values of parameters leading to observable signals. This indicates that, given a certain moderate fine-tuning, the minimal left-right symmetric model with scalar triplets features another powerful probe which can lead to either novel constraints or remarkable discoveries in the near future. Let us note that some of our results, such as the full set of thermal masses, have to the best of our knowledge not been presented before and might be useful for future studies, in particular in the context of electroweak baryogenesis.

A discussion of Christopher Wren's inaugural address of 1657, and how it came to be widely misquoted so as to appear to be referring to the future discovery of exoplanets instead of contemporary discoveries in the solar system.

Daniel Hartley, Christian Käding, Richard Howl, Ivette Fuentes

20 pages, 6 figures

We propose an experiment based on a Bose-Einstein condensate interferometer for strongly constraining fifth-force models. Additional scalar fields from modified gravity or higher dimensional theories may account for dark energy and the accelerating expansion of the Universe. These theories have led to proposed screening mechanisms to fit within the tight experimental bounds on fifth-force searches. We show that our proposed experiment would greatly improve the existing constraints on these screening models by many orders of magnitude, entirely eliminating the remaining parameter space of the simplest of these models.

The constraints on tidal deformability $\Lambda$ of neutron stars are first extracted from GW170817 by LIGO and Virgo Collaborations but the relation between radius $R$ and tidal deformability $\Lambda$ is still nuder debate. Using an isospin-dependent parameterized equation of state (EOS), we study the relation between $R$ and $\Lambda$ of neutron stars and its dependence on parameters of symmetry energy $E_{\rm sym}$ and EOS of symmetric nuclear matter $E_0$ when the mass is fixed as $1.4$ $M_\odot$, $1.0$ $M_\odot$, and $1.8$ $M_\odot$, respectively. We find that, though the changes of high order parameters of $E_{\rm sym}$ and $E_0$ can shift the individual values of $R_{1.4}$ and $\Lambda_{1.4}$ to different values, the $R_{1.4}\sim\Lambda_{1.4}$ relation approximately locates at the same fitted curve. The slope of symmetry energy $L$ plays the dominated role in determining the $R_{1.4}\sim\Lambda_{1.4}$ relation. By checking the mass dependence of $R\sim\Lambda$ relation, the well fitted $R\sim\Lambda$ relation for 1.4 $M_\odot$ is broken for massive neutron stars.

We study the phenomenology associated to non-minimally coupled dark matter. In particular, we consider the model where the non-minimal coupling arises from the formation of relativistic Bose-Einstein condensates in high density regions of dark matter [1]. This non-minimal coupling is of Horndeski type and leads to a local modification of the speed of gravity with respect to the speed of light. Therefore we can constrain the model by using the joint detection of GW170817 and GRB170817A. We show that the constraints obtained in this way are quite tight, if the dark matter field oscillates freely, whereas they are substantially weakened, if the oscillations are damped by the non-minimal coupling.

Decades of research show that students learn more in classes that utilize active learning than they do in traditional, lecture-only classes. Active learning also reduces the achievement gaps that are often present between various demographic groups. Given these well-established results, instructors of upper-division astronomy courses may decide to search the astronomy education research literature in hopes of finding some guidance on common student difficulties, as well as research-validated and research-based active learning curricula. But their search will be in vain. The current literature on upper-division astronomy is essentially non-existent. This is a shame,since many upper-division astronomy students will experience conceptual and problem-solving difficulties with the quantitative problems they encounter. These difficulties may exist even if students have a strong background in mathematics. This is because we often hide multiple ideas and intellectual steps in the problem statement and in the few brief lines of mathematics that are frequently considered sufficient for a complete solution. In this paper, I examine one quantitative problem that is representative of those that upper-division astronomy students are expected to solve. I list many of the subtle pieces of information that students need to understand in order to advance toward a solution and I describe how such a list can be used to generate Peer Instruction (PI) questions. I also provide guidelines for instructors who wish to develop and implement their own PI questions. These PI questions can be used to increase the amount of active learning that occurs in an upper-division astronomy course. They help develop students' understandings of symbolic, mathematical representations and they help improve students' problem-solving skills.