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We present the observed HI size-mass relation of $204$ galaxies from the MIGHTEE Survey Early Science data. The high sensitivity of MeerKAT allows us to detect galaxies spanning more than 4 orders of magnitude in HI mass, ranging from dwarf galaxies to massive spirals, and including all morphological types. This is the first time the relation has been explored on a blind homogeneous data set which extends over a previously unexplored redshift range of $0 < z < 0.084$, i.e. a period of around one billion years in cosmic time. The sample follows the same tight logarithmic relation derived from previous work, between the diameter ($D_{\rm HI}$) and the mass ($M_{\rm HI}$) of HI discs. We measure a slope of $0.501\pm 0.008$, an intercept of $-3.252^{+0.073}_{-0.074}$, and an observed scatter of $0.057$ dex. For the first time, we quantify the intrinsic scatter of $0.054 \pm 0.003$ dex (${\sim} 10 \%$), which provides a constraint for cosmological simulations of galaxy formation and evolution. We derive the relation as a function of galaxy type and find that their intrinsic scatters and slopes are consistent within the errors. We also calculate the $D_{\rm HI} - M_{\rm HI}$ relation for two redshift bins and do not find any evidence for evolution with redshift. These results suggest that over a period of one billion years in lookback time, galaxy discs have not undergone significant evolution in their gas distribution and mean surface mass density, indicating a lack of dependence on both morphological type and redshift., 10 pages, 5 figures, accepted for publication in MNRAS

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Monthly Notices of the Royal Astronomical Society 510.1 (2022): 292-308 is available online at: https://academic.oup.com/mnras/article-abstract/510/1/292/6442269?redirectedFrom=fulltext#no-access-message, We study the clustering of H i intensity maps (IM) produced from simulations with a focus on baryonic acoustic oscillations (BAOs) and the effects induced by telescope beam smoothing and foreground cleaning. We start by creating an H i catalogue at z = 1.321 based on the Semi-Analytic Galaxy Evolution (SAGE) model applied to the UNIT simulations. With this catalogue, we investigate the relation between model H i and the dark matter haloes and we also study the abundance of H i, Omega rm{H small {rm I}}, predicted by this model. We then create synthetic H i IM with a nearest-grid-point approach. In order to simulate the telescope beam effect, a Gaussian smoothing is applied on the plane perpendicular to the line of sight. The effect of foreground removal methods is simulated by exponentially damping the largest wavelength Fourier modes on the radial direction. We study the anisotropic 2-point correlation function (2PCF) ζ(rpdbl, rpdbl) and how it is affected by the aforementioned observational effects. In order to better isolate the BAO signal, we study several 2PCF μ-wedges (with a restricted range of orientations μ) tailored to address the systematics effects and we compare them with different definitions of radial 2PCFs. Finally, we discuss our findings in the context of an SKA-like survey, finding a clear BAO signal in most of the estimators here proposed

We present the serendipitous discovery of a galaxy group in the XMM-LSS field with MIGHTEE Early Science observations. 20 galaxies are detected in H i in this z ∼0.044 group, with a 3σ column density sensitivity of NHI = 1.6 × 1020 cm-2. This group has not been previously identified, despite residing in a well-studied extragalactic legacy field. We present spatially resolved H i total intensity and velocity maps for each of the objects which reveal environmental influence through disturbed morphologies. The group has a dynamical mass of log10(Mdyn/M⊙) = 12.32, and is unusually gas-rich, with an H i-to-stellar mass ratio of log10(f∗HI) = -0.2, which is 0.7 dex greater than expected. The group's high H i content, spatial, velocity, and identified galaxy type distributions strongly suggest that it is in the early stages of its assembly. The discovery of this galaxy group is an example of the importance of mapping spatially resolved H i in a wide range of environments, including galaxy groups. This scientific goal has been dramatically enhanced by the high sensitivity, large field-of-view, and wide instantaneous bandwidth of the MeerKAT telescope. © 2021 The Author(s)., The research of SR and RPD is supported by the South African Research Chairs Initiative (grant ID 77948) of the Department of Science and Innovation and National Research Foundation. SR, RPD, and MJJ acknowledge the financial assistance of the South African Radio Astronomy Observatory (SARAO) towards this research (www.ska.ac.za). The HSC instrumentation and software were developed by the National Astronomical Observatory of Japan (NAOJ), the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IMPU), the University of Tokyo, the High Energy Accelerator Research Organization (KEK), the Academia Sinica Institute for Astronomy and Astrophysics in Taiwan (ASIAA), and Princeton University. Funding was contributed by the FIRST program from Japanese Cabinet Office, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Society for the Promotion of Science (JSPS), Japan Science and Technology Agency (JST), the Toray Science Foundation, NAOJ, Kavli IPMU, KEK, ASIAA, and Princeton University. AAP acknowledges the support of the STFC consolidated grant ST/S000488/1. WM is supported by the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation. RB acknowledges support from the Glasstone Foundation and from an STFC Ernest Rutherford Fellowship [grant number ST/T003596/1]. NM acknowledges support from the Bundesministerium für Bildung und Forschung (BMBF) award 05A20WM4. MJJ acknowledges support from the UK Science and Technology Facilities Council [ST/S000488/1 and ST/N000919/1]. MT and MJJ acknowledge support from the Oxford Hintze Centre for Astrophysical Surveys which are funded through generous support from the Hintze Family Charitable Foundation. LVM acknowledges financial support from the grants AYA2015-65973-C3-1-R and RTI2018-096228-B-C31 (MINECO/FEDER, UE), as well as from the State Agency for Research of the Spanish Ministry of Science, Innovation and Universities through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This research made use of Astropy,4 a community-developed core PYTHON package for Astronomy. MG and JC acknowledge financial support from the Inter-University Institute for Data Intensive Astronomy (IDIA).

While most purpose-built 21cm intensity mapping experiments are close-packed interferometer arrays, general-purpose dish arrays should also be capable of measuring the cosmological 21cm signal. This can be achieved most efficiently if the array is used as a collection of scanning autocorrelation dishes rather than as an interferometer. As a first step towards demonstrating the feasibility of this observing strategy, we show that we are able to successfully calibrate dual-polarisation autocorrelation data from 64 MeerKAT dishes in the L-band (856-1712 MHz, 4096 channels), with 10.5 hours of data retained from six nights of observing. We describe our calibration pipeline, which is based on multi-level RFI flagging, periodic noise diode injection to stabilise gain drifts and an absolute calibration based on a multi-component sky model. We show that it is sufficiently accurate to recover maps of diffuse celestial emission and point sources over a 10 deg x 30 deg patch of the sky overlapping with the WiggleZ 11hr field. The reconstructed maps have a good level of consistency between per-dish maps and external datasets, with the estimated thermal noise limited to 1.4 x the theoretical noise level (~ 2 mK). The residual maps have rms amplitudes below 0.1 K, corresponding to, 24 pages, 34 figures, accepted for publication in MNRAS

This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.00650.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic ofKorea), in cooperationwith theRepublic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The authors are grateful to Krajnovi ' c et al. for the Kinemetry code. The authors thank the referee, Prof. JeffreyKenney, for valuable comments and suggestions that improved this paper. The authors also thank the support of the Astronomical Data Center of the National Astronomical Observatory of Japan, and Anthony Moraghan for assistance on the computational facilities and resources at Academia Sinica Institute of Astronomy and Astrophysics (ASIAA). DE acknowledges support from a Beatriz Galindo senior fellowship (BG20/00224) from the SpanishMinistry of Science and Innovation. YTW wishes to thank Dr. Yu-Nung Su and Dr. Sheng-Yuan Liu for hosting her visit at ASIAA in 2020., We present results obtained from ALMA CO (2–1) data of the double-barred galaxy NGC3504.With three times higher angular resolution (∼0. 8) than previous studies, our observations reveal an inner molecular gas bar, a nuclear ring, and four inner spiral arm-like structures in the central 1-kpc region. Furthermore, the CO emission is clearly aligned with the two dust lanes in the outer bar region, with differences in shape and intensity between them. The total molecular gas mass in the observed region (50 arcsec×57 arcsec) is estimated to be∼3.1 × 109M , which is 17 per cent of the stellarmass.We used the Kinemetry package to fit the velocity field and found that circular motion strongly dominates at R = 0.3–0.8 kpc, but radial motion becomes important at R < 0.3 kpc and R = 1.0–2.5 kpc, which is expected due to the presence of the inner and outer bars. Finally, assuming that the gas moves along the dust lanes in the bar rotating frame, we derived the pattern speed of the outer bar to be 18 ± 5 kms−1 kpc−1, the average streaming velocities on each of the two dust lanes to be 165 and 221 km s−1, and the total mass inflow rate along the dust lanes to be 12M yr−1. Our results give a new example of an inner gas bar within a gas-rich double-barred galaxy and suggest that the formation of double-barred galaxies could be associated with the existence of such gas structures., Spanish Government BG20/00224

Acknowledgements. We appreciate the detailed and useful comments of the referee which helped to improve the clarity of the paper. We acknowledge support (proyect AYA2017-84897-P) from the Spanish Ministerio de Economía y Competitividad, from the European Regional Development Funds (FEDER) and the Junta de Andalucía (Spain) grants FQM108. This work is based on observations carried out under project numbers 075-19 with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). J. F.-B. acknowledges support through the RAVET project by the grant PID2019-107427GB-C32 from the Spanish Ministry of Science, Innovation and Universities (MCIU), and through the IAC project TRACES which is partially supported through the state budget and the regional budget of the Consejería de Economía, Industria, Comercio y Conocimiento of the Canary Islands Autonomous Community. S.D.P. is grateful to the Fonds de Recherche du Québec – Nature et Technologies and acknowledge financial support from the Spanish Ministerio de Economía y Competitividad under grants AYA2016-79724-C4-4-P and PID2019-107408GB-C44, from Junta de Andalucía Excellence Project P18-FR-2664, and also acknowledges support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This research made use of Astropy, a community-developed core Python (http://www.python.org) package for Astronomy (Astropy Collaboration 2013, 2018); ipython (Pérez & Granger 2007); mat-plotlib (Hunter 2007); SciPy, a collection of open source software for scientific computing in Python (Virtanen et al. 2020); APLpy, an open-source plotting package for Python (Robitaille & Bressert 2012; Robitaille 2019); and NumPy, a structure for efficient numerical computation (van der Walt et al. 2011)., Context. Voids are the most under-dense large-scale regions in the Universe. Galaxies inhabiting voids are one of the keys for understanding the intrinsic processes of galaxy evolution, as external factors such as multiple galaxy mergers or a dense self-collapsing environment are negligible. Aims. We present the first molecular gas mass survey of void galaxies. We compare these new data together with data for the atomic gas mass (MH I) and star formation rate (SFR) from the literature to those of galaxies in filaments and walls in order to better understand how molecular gas and star formation are related to the large-scale environment. Methods. We observed at the IRAM 30 m telescope the CO(1-0) and CO(2-1) emission of 20 void galaxies selected from the Void Galaxy Survey, with a stellar mass range from 108.5 to 1010.3 M·. We detected 15 objects in at least one CO line. We compared the molecular gas mass (MH2), the star formation efficiency (SFE = SFR/MH2), the atomic gas mass, the molecular-to-atomic gas mass ratio, and the specific star formation rate (sSFR) of the void galaxies with two control samples of galaxies in filaments and walls, selected from xCOLD GASS and EDGE-CALIFA, for different stellar mass bins and taking the star formation activity into account. Results. In general, we do not find any significant differences between void galaxies and the control sample. In particular, we do not find any evidence for a difference in the molecular gas mass or molecular gas mass fraction. For the other parameters (SFE, atomic gas mass, molecular-to-atomic gas mass ratio, and sSFR), we also find similar (within the errors) mean values between void and filament and wall galaxies when the sample is limited to star-forming galaxies. We find no evidence for an enhanced sSFR in void galaxies. Some tentative differences emerge when trends with stellar mass are studied: The SFE of void galaxies might be lower than in filament and wall galaxies for low stellar masses, and there might be a trend of increasing deficiency in the HI content in void galaxies compared to galaxies in filaments and walls for higher stellar masses, accompanied by an increase in the molecular-to-atomic gas mass ratio. However, all trends with stellar mass are based on a low number of galaxies and need to be confirmed for a larger sample. Conclusions. The results for the molecular gas mass for a sample of 20 voids galaxies allowed us to make a statistical comparison to galaxies in filaments and walls for the first time. We do not find any significant differences of the molecular gas properties and the SFE, but we note that a larger sample is necessary to confirm this and be sensitive to subtle trends., Consejería de Economía, Industria, Comercio y Conocimiento, INSU, Instituto de Astrofísica de Andalucía SEV-2017-0709, Junta de Andalucía Excellence Project P18-FR-2664, State Agency for Research, Ministerio de Ciencia, Innovación y Universidades, Fonds de recherche du Québec – Nature et technologies AYA2016-79724-C4-4-P, PID2019-107408GB-C44, Ministerio de Economía y Competitividad, Centre National de la Recherche Scientifique PID2019-107427GB-C32, European Regional Development Fund, Junta de Andalucía FQM108

We estimate the H i mass function (HIMF) of galaxies in groups based on thousands of ALFALFA (Arecibo Legacy Fast ALFA survey) H i detections within the galaxy groups of four widely used SDSS (Sloan Digital Sky Survey) group catalogues. Although differences between the catalogues mean that there is no one definitive group galaxy HIMF, in general we find that the low-mass slope is flat, in agreement with studies based on small samples of individual groups, and that the 'knee' mass is slightly higher than that of the global HIMF of the full ALFALFA sample. We find that the observed fraction of ALFALFA galaxies in groups is approximately 22 per cent. These group galaxies were removed from the full ALFALFA source catalogue to calculate the field HIMF using the remaining galaxies. Comparison between the field and group HIMFs reveals that group galaxies make only a small contribution to the global HIMF as most ALFALFA galaxies are in the field, but beyond the HIMF 'knee' group galaxies dominate. Finally, we attempt to separate the group galaxy HIMF into bins of group halo mass, but find that too few low-mass galaxies are detected in the most massive groups to tightly constrain the slope, owing to the rarity of such groups in the nearby Universe where low-mass galaxies are detectable with existing H i surveys.© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society, We acknowledge the work of the entire ALFALFA team for observing, flagging, and performing signal extraction. We thank the anonymous referee for their suggestions that helped to improve this paper. MGJ is supported by a Juan de la Cierva formacion´ fellowship (FJCI-2016-29685) from the Spanish Ministerio de Ciencia, Innovacion y Universidades (MCIU). MGJ and LVM ´ also acknowledge support from the grants AYA2015-65973-C3-1- R (MINECO/FEDER, UE) and RTI2018-096228-B-C31 (MCIU). The research of KMH is supported by the under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement nr. 291531. EAKA is supported by the WISE research programme, which is financed by the Netherlands Organisation for Scientific Research (NWO). This work has been supported by the State Agency for Research of the Spanish MCIU through the ‘Centro de Excelencia Severo Ochoa’ award to the Instituto de Astrof´ısica de Andaluc´ıa (SEV-2017-0709). This research was supported by the Munich Institute for Astro- and Particle Physics (MIAPP) which is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)

Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., A fully sampled and hitherto highest resolution and sensitivity observation of neutral hydrogen (H I) in the Leo Triplet (NGC 3628, M 65/NGC 3623, and M 66/NGC 3627) reveals six H I structures beyond the three galaxies. We present detailed results of the morphologies and kinematics of these structures, which can be used for future simulations. In particular, we detect a two-arm structure in the plume of NGC 3628 for the first time, which can be explained by a tidal interaction model. The optical counterpart of the plume is mainly associated with the southern arm. The connecting part (base) of the plume (directed eastward) with NGC 3628 is located at the blueshifted (western) side of NGC 3628. Two bases appear to be associated with the two arms of the plume. A clump with a reversed velocity gradient (relative to the velocity gradient of M 66) and a newly detected tail, that is to say M 66SE, is found in the southeast of M 66. We suspect that M 66SE represents gas from NGC 3628, which was captured by M 66 in the recent interaction between the two galaxies. Meanwhile gas is falling toward M 66, resulting in features previously observed in the southeastern part of M 66, such as large line widths and double peaks. An upside-down “Y”-shaped H I gas component (M 65S) is detected in the south of M 65, which suggests that M 65 may also have been involved in the interaction. We strongly encourage modern hydrodynamical simulations of this interacting group of galaxies to reveal the origin of the gaseous debris surrounding all three galaxies. © G. Wu et al. 2022., This work was funded by the CAS “Light of West China” Program under grant No. 2018-XBQNXZ-B-024 and the National Natural Science foundation of China under grant Nos. 11433008, 12173075, 12103082, and 11973076. G.W. acknowledges the support from Youth Innovation Promotion Association CAS. DMD acknowledges financial support from the Talentia Senior Program (through the incentive ASE-136) from Secretaría General de Universidades, Investigación y Tecnología, de la Junta de Andalucía. DMD acknowledges funding from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). DMD acknowledges funding from the State Agency for Research of the Spanish MCI (Project PID2020-114581GB-C21/AEI/10.13039/501100011033). This research made use of astrodendro, a Python package to compute dendrograms of Astronomical data (http://www.dendrograms.org/). The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by the University of Central Florida and in alliance with Universidad Ana G. Mendez, and Yang Enterprises, Inc.

We present results from our analysis of the Hydra I cluster observed in neutral atomic hydrogen (H I) as part of the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). These WALLABY observations cover a 60-square-degree field of view with uniform sensitivity and a spatial resolution of 30 arcsec. We use these wide-field observations to investigate the effect of galaxy environment on H I gas removal and star formation quenching by comparing the properties of cluster, infall, and field galaxies extending up to ∼5R200 from the cluster centre. We find a sharp decrease in the H I-detected fraction of infalling galaxies at a projected distance of ∼1.5R200 from the cluster centre from ∼85 per cent to ∼35 per cent⁠. We see evidence for the environment removing gas from the outskirts of H I-detected cluster and infall galaxies through the decrease in the H I to r-band optical disc diameter ratio. These galaxies lie on the star-forming main sequence, indicating that gas removal is not yet affecting the inner star-forming discs and is limited to the galaxy outskirts. Although we do not detect galaxies undergoing galaxy-wide quenching, we do observe a reduction in recent star formation in the outer disc of cluster galaxies, which is likely due to the smaller gas reservoirs present beyond the optical radius in these galaxies. Stacking of H I non-detections with H I masses below MHI≲108.4M⊙ will be required to probe the H I of galaxies undergoing quenching at distances ≳60 Mpc with WALLABY. © 2021 The Author(s)., This research was conducted by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. The Australian SKA Pathfinder is part of the Australia Telescope National Facility which is managed by the Commonwealth Scientific and Industrial Research Organisation (CSIRO). Operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy. ASKAP uses the resources of the Pawsey Supercomputing Centre. Establishment of ASKAP, the Murchison Radio-astronomy Observatory (MRO), and the Pawsey Supercomputing Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. We acknowledge the Wajarri Yamatji as the traditional owners of the Observatory site. We also thank the MRO site staff. This paper includes archived data obtained through the CSIRO ASKAP Science Data Archive, CASDA (http://data.csiro.au). LC acknowledges support from the Australian Research Council Discovery Project and Future Fellowship funding schemes (DP210100337, FT180100066). DO is a recipient of an Australian Research Council Future Fellowship (FT190100083) funded by the Australian Government. JR acknowledges support from the State Research Agency (AEI-MCINN) of the Spanish Ministry of Science and Innovation under the grant ‘The structure and evolution of galaxies and their central regions’ with reference PID2019-105602GB-I00/10.13039/501100011033. LVM acknowledges financial support from the State Agency for Research of the Spanish Ministry of Science, Innovation and Universities through the ‘Center of Excellence Severo Ochoa’ awarded to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), from the grant RTI2018-096228-B-C31 (Ministry of Science, Innovation and Universities/State Agency for Research/European Regional Development Funds, European Union), from the grant RED2018-102587-T (Spanish Ministry of Science, Innovation and Universities/State Agency for Research), and grant IAA4SKA (Ref. P18-RT-3082) from the Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades de la Junta de Andalucia and the European Regional Development Fund from the European Union. AB acknowledges support from the Centre National d’Etudes Spatiales (CNES), France. ARHS acknowledges receipt of the Jim Buckee Fellowship at ICRAR-UWA. SHO acknowledges support from the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT: MSIT) (No. NRF-2020R1A2C1008706). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 679627; project name FORNAX). This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. This publication makes use of data products from the Wide-field Infrared Survey Explorer (WISE), which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This work is based in part on observations made with the Galaxy Evolution Explorer (GALEX). GALEX is a NASA Small Explorer, whose mission was developed in cooperation with the Centre National d’Etudes Spatiales (CNES) of France and the Korean Ministry of Science and Technology. GALEX is operated for NASA by the California Institute of Technology under NASA contract NAS5-98034.

We extend the analysis of Bok et al. (2020) in which the H I content of isolated galaxies from the AMIGA (Analysis of the interstellar Medium in Isolated GAlaxies) sample and selected paired galaxies from ALFALFA (Arecibo Legacy Fast ALFA) were examined as a potential driver of galaxy location on the WISE (Wide-field Infrared Survey Explorer) mid-infrared SFR–M⋆ sequence. By further characterizing the isolated and pair galaxy samples, i.e. in terms of optical galaxy morphology, a more detailed and quantitative description of local galaxy environment by way of the local number density (η) and tidal strength (Q) parameters, star formation efficiency (SFEH I⁠), and H I integrated profile asymmetries, we present plausible pathways for the broadening of the pair sample H I deficiency distribution towards both high and low deficiencies compared to the narrower isolated galaxy sample distribution (i.e. σPAIRS = 0.34 versus σAMIGA = 0.28). We associate the gas-rich tail of the pair deficiency distribution with the highest Q values, large profile asymmetries, and low SFEs. From this, we infer that merger activity is enhancing gas supplies, as well as disrupting the efficiency of star formation, via strong gravitational torques. The gas-poor wing of the deficiency distribution appears to be populated with galaxies in denser environments (with larger η values on average), more akin to groups. Despite our gas-rich selection criterion, there is a small population of early-type galaxies in the pair sample, which primarily fall in the positive deficiency wing of the distribution. These results suggest that a combination of a denser galaxy environment, early-type morphology, and higher stellar mass is contributing to the broadening of the deficiency distribution towards larger deficiencies. © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society., This work is based on the research supported in part by the National Research Foundation of South Africa (grant number UIDs: 101099 and 111745). JB additionally acknowledges support from the DST-NRF Professional Development Programme (PDP) and the University of Cape Town. MC is a recipient of an Australian Research Council Future Fellowship (project number FT170100273) funded by the Australian Government. THJ acknowledges funding from the National Research Foundation under the Research Career Advancement and South African Research Chair Initiative programmes, respectively. We acknowledge the work of the entire ALFALFA team for observing, flagging, and performing signal extraction. MGJ was supported by a Juan de la Cierva formación fellowship (FJCI-2016-29685) from the Spanish Ministerio de Ciencia, Innovacion y Universidades (MCIU). MGJ also acknowledges support from the grants AYA2015-65973-C3-1-R (MINECO/FEDER, UE) and RTI2018-096228-B-C31 (MCIU). This work has been supported by the State Agency for Research of the Spanish MCIU through the ‘Centro de Excelencia Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This publication makes use of data products from the WISE, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This work also utilizes data from ALFALFA survey data set obtained with the Arecibo L-band Feed Array (ALFA) on the Arecibo 305 m telescope. Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under Cooperative Agreement with the U.S. National Science Foundation. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS website is http://www.sdss.org/. In addition, we make use of data from the SDSS (SDSS DR7). The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington. LVM acknowledges financial support from the grant IAA4SKA (Ref. R18-RT-3082) from the Economic Transformation, Industry, Knowledge and Universities Council of the Regional Government of Andalusia and the European Regional Development Fund from the European Union.

Full list of authors: Jackson, N.; Badole, S.; Morgan, J.; Chhetri, R.; Prūsis, K.; Nikolajevs, A.; Morabito, L.; Brentjens, M.; Sweijen, F.; Iacobelli, M.; Orrù, E.; Sluman, J.; Blaauw, R.; Mulder, H.; van Dijk, P.; Mooney, S.; Deller, A.; Moldon, J.; Callingham, J. R.; Harwood, J.; Hardcastle, M.; Heald, G.; Drabent, A.; McKean, J. P.; Asgekar, A.; Avruch, I. M.; Bentum, M. J.; Bonafede, A.; Brouw, W. N.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Coolen, A.; Corstanje, A.; Damstra, S.; Duscha, S.; Eislöffel, J.; Falcke, H.; Garrett, M.; de Gasperin, F.; Griessmeier, J. -M.; Gunst, A. W.; van Haarlem, M. P.; Hoeft, M.; van der Horst, A. J.; Jütte, E.; Koopmans, L. V. E.; Krankowski, A.; Maat, P.; Mann, G.; Miley, G. K.; Nelles, A.; Norden, M.; Paas, M.; Pandey, V. N.; Pandey-Pommier, M.; Pizzo, R. F.; Reich, W.; Rothkaehl, H.; Rowlinson, A.; Ruiter, M.; Shulevski, A.; Schwarz, D. J.; Smirnov, O.; Tagger, M.; Vocks, C.; van Weeren, R. J.; Wijers, R.; Wucknitz, O.; Zarka, P.; Zensus, J. A.; Zucca, P., The Low-Frequency Array (LOFAR) Long-Baseline Calibrator Survey (LBCS) was conducted between 2014 and 2019 in order to obtain a set of suitable calibrators for the LOFAR array. In this paper, we present the complete survey, building on the preliminary analysis published in 2016 which covered approximately half the survey area. The final catalogue consists of 30 006 observations of 24 713 sources in the northern sky, selected for a combination of high low-frequency radio flux density and flat spectral index using existing surveys (WENSS, NVSS, VLSS, and MSSS). Approximately one calibrator per square degree, suitable for calibration of ≥200 km baselines is identified by the detection of compact flux density, for declinations north of 30° and away from the Galactic plane, with a considerably lower density south of this point due to relative difficulty in selecting flat-spectrum candidate sources in this area of the sky. The catalogue contains indicators of degree of correlated flux on baselines between the Dutch core and each of the international stations, involving a maximum baseline length of nearly 2000 km, for all of the observations. Use of the VLBA calibrator list, together with statistical arguments by comparison with flux densities from lower-resolution catalogues, allow us to establish a rough flux density scale for the LBCS observations, so that LBCS statistics can be used to estimate compact flux densities on scales between 300 mas and 2′′, for sources observed in the survey. The survey is used to estimate the phase coherence time of the ionosphere for the LOFAR international baselines, with median phase coherence times of about 2 min varying by a few tens of percent between theshortest and longest baselines. The LBCS can be used to assess the structures of point sources in lower-resolution surveys, with significant reductions in the degree of coherence in these sources on scales between 2′′ and 300 mas. The LBCS survey sources show a greater incidence of compact flux density in quasars than in radio galaxies, consistent with unified schemes of radio sources. Comparison with samples of sources from interplanetary scintillation (IPS) studies with the Murchison Widefield Array shows consistent patterns of detection of compact structure in sources observed both interferometrically with LOFAR and using IPS. © ESO 2022., Support for the operation of the MWA is provided by the Australian Government (NCRIS), under a contract to Curtin University administered by Astronomy Australia Limited. We acknowledge the Pawsey Supercomputing Centre which is supported by the Western Australian and Australian Governments. A.D. acknowledges support by the BMBF Verbundforschung under the grant 052020. L.K.M. is grateful for support from the UKRI Future Leaders Fellowship (grant MR/T042842/1). J. Moldón acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and from the grant RTI2018-096228-B-C31 (MICIU/FEDER, EU). J.P.M. acknowledges support from the Netherlands Organization for Scientific Research (NWO, project number 629.001.023) and the Chinese Academy of Sciences (CAS, project number 114A11KYSB20170054).

We present the blind Westerbork Coma Survey probing the H I content of the Coma galaxy cluster with the Westerbork Synthesis Radio Telescope. The survey covers the inner ∼1 Mpc around the cluster centre, extending out to 1.5 Mpc towards the south-western NGC 4839 group. The survey probes the atomic gas in the entire Coma volume down to a sensitivity of ∼1019 cm−2 and 108 M⊙. Combining automated source finding with source extraction at optical redshifts and visual verification, we obtained 40 H I detections of which 24 are new. Over half of the sample displays perturbed H I morphologies indicative of an ongoing interaction with the cluster environment. With the use of ancillary UV and mid-IR, data we measured their stellar masses and star formation rates and compared the H I properties to a set of field galaxies spanning a similar stellar mass and star formation rate range. We find that ∼75% of H I-selected Coma galaxies have simultaneously enhanced star formation rates (by ∼0.2 dex) and are H I deficient (by ∼0.5 dex) compared to field galaxies of the same stellar mass. According to our toy model, the simultaneous H I deficiency and enhanced star formation activity can be attributed to either H I stripping of already highly star forming galaxies on a very short timescale, while their H2 content remains largely unaffected, or to H I stripping coupled to a temporary boost of the H I-to-H2 conversion, causing a brief starburst phase triggered by ram pressure before eventually quenching the galaxy. © ESO 2022., This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 679627; project name FORNAX). JMvdH and KMH acknowledge funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 291531 (‘HIStoryNU’). LC acknowledges support from the Australian Research Councils Discovery Project and Future Fellowship funding schemes (DP210100337,FT180100066). Parts of this research were conducted by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. JH acknowledges research funding from the South African Radio Astronomy Observatory. MV acknowledges support by the Netherlands Foundation for Scientific Research (NWO) through VICI grant 016.130.338. KMH acknowledges funding from the State Agency for Research of the Spanish Ministry of Science, Innovation and Universities through the “Center of Excellence Severo Ochoa” awarded to the Instituto de Astrofísica de Andalucía (SEV-2017-0709); from grant RTI2018-096228-B-C31 (Ministry of Science, Innovation and Universities / State Agency for Research / European Regional Development Funds, European Union); and from the coordination of the participation in SKA-SPAIN, funded by the Ministry of Science and innovation (MICIN).

Dusty star-forming galaxies (DSFGs) at redshift z$\geq$1 are among the most vigorously star-forming galaxies in the Universe. However, their dense ($\geq$10$^5$ cm$^{-3}$ ) gas phase - typically traced by HCN(1-0) - remains almost entirely unexplored: only two DSFGs have been detected in HCN(1-0) to date. We present results of a JVLA survey of the J=1-0 transition of HCN, HCO+, and HNC(1-0) in six strongly lensed DSFGs at z = 2.5 - 3.3, effectively doubling the number of DSFGs with deep observations of these lines. We detect HCN(1-0) emission in one source (J1202+5354, 4.4$\sigma$), with a tentative HCO+ (1-0) detection in another (J1609+6045, 3.3$\sigma$). Spectral stacking yields strict upper limits on the HCN/FIR ($\leq$3.6$\times$10$^{-4}$) and HCN/CO(1-0) ratios ($\leq$0.045). The inferred HCN/FIR ratios (a proxy for the star-formation efficiency) are consistent with those in z$\sim$0 FIR-luminous starbursts. However, the HCN/CO ratios - a proxy for the dense-gas fraction - are a factor of a few lower than suggested by the two previous DSFG detections. Our results imply that most DSFGs have low dense-gas fractions. A comparison with Krumholz & Thompson (2007) models of star-forming galaxies indicates that the bulk of gas in DSFGs is at lower densities ($\approx$10$^2$ cm$^{-3}$ ), similar to "normal" star-forming galaxies, rather than ultraluminous starbursts., Comment: Submitted to A&A 28th April 2022, accepted 19th July 2022

Context. The properties of galaxies at redshift z>6 hold the key to our understanding of the early stages of galaxy evolution and can potentially identify the sources of the ultraviolet radiation that give rise to the epoch of reionisation. The far-infrared cooling line of [C II] at 158 mu m is known to be bright and correlate with the star formation rate (SFR) of low-redshift galaxies, and hence is also suggested to be an important tracer of star formation and interstellar medium properties for very high-redshift galaxies.Aims. With the aim to study the interstellar medium properties of gravitationally lensed galaxies at z>6, we search for [C II] and thermal dust emission in a sample of 52 > 6 galaxies observed by the ALMA Lensing Cluster Survey.Methods. We perform our analysis using LINESTACKER, stacking both [C II] and continuum emission. The target sample is selected from multiple catalogues, and the sample galaxies have spectroscopic redshift or low-uncertainty photometric redshifts (sigma(z)Results. Our analyses find no detection of either [C II] or continuum. An upper limit on L-[CII] is derived, implying that [C II] remains marginally consistent for low-SFR z>6 galaxies but likely is under-luminous compared to the local L-[CII]-SFR relationship. We discuss potential biases and possible physical effects that may be the cause of the non-detection. Further, the upper limit on the dust continuum implies that less than half of the star formation is obscured.

Full list of authors: Namumba, B.; Koribalski, B. S.; Józsa, G. I. G.; Lee-Waddell, K.; Jones, M. G.; Carignan, C.; Verdes-Montenegro, L.; Ianjamasimanana, R.; de Blok, W. J. G.; Cluver, M.; Garrido, J.; Sánchez-Expósito, S.; Ramaila, A. J. T.; Thorat, K.; Andati, L. A. L.; Hugo, B. V.; Kleiner, D.; Kamphuis, P.; Serra, P.; Smirnov, O. M.; Maccagni, F. M.; Makhathini, S.; Molnár, D. Cs.; Perkins, S.; Ramatsoku, M.; White, S. V.; Loi, F., We report the discovery of large amounts of previously undetected cold neutral atomic hydrogen (H I) around the core triplet galaxies in the nearby NGC 7232 galaxy group with MeerKAT. With a physical resolution of ∼1 kpc, we detect a complex web of low-surface-brightness H I emission down to a 4σ column density level of ∼1 × 1019 cm−2 (over 44 km s−1). The newly discovered H I streams extend over ∼20 arcmin corresponding to 140 kpc in projection. This is approximately three times the H I extent of the galaxy triplet (52 kpc). The H I debris has an H I mass of ∼6.6 × 109 M⊙, more than 50 per cent of the total H I mass of the triplet. Within the galaxy triplet, NGC 7233 and NGC 7232 have lost a significant amount of H I while NGC 7232B appears to have an excess of H I. The H I deficiency in NGC 7232 and NGC 7233 indicates that galaxy–galaxy interaction in the group concentrates on this galaxy pair while the other disc galaxies have visited them over time. In comparison to the AMIGA sample of isolated galaxies, we find that with regards to its total H I mass the NGC 7232/3 galaxy triplet is not H I-deficient. Despite the many interactions associated to the triplet galaxies, no H I seems to have been lost from the group (yet). © 2021 The Author(s)., The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Innovation. BN’s research is supported by the South African Radio Astronomy Observatory (SARAO). We acknowledge the Inter-University Institute for Data Intensive Astronomy (IDIA) for supporting us with the data intensive cloud for data processing. IDIA is a South African university partnership involving the University of Cape Town, the University of Pretoria, and the University of the Western Cape. BN acknowledges financial support from the CSIC Program of Scientific Cooperation for Development i-COOP+2019. The research of OS is supported by the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation. PK is partially supported by the BMBF project 05A17PC2 for D-MeerKAT. LVM, MGJ, and BN acknowledge financial support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). BN acknowledges the discussion with the AMIGA team at IAA regarding data reduction and analysis. LVM, MJ, SSE, and JG acknowledge as well support from the grants AYA2015-65973-C3-1-R (MINECO/FEDER, UE) and RTI2018-096228-B-C31 (MCIU/AEI/FEDER,UE). MGJ fellowship was supported by a Juan de la Cierva formación fellowship. The work of WJGdB has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 882793/MeerGas). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 679627; project name FORNAX). MEC is a recipient of an Australian Research Council Future Fellowship (project No. FT170100273) funded by the Australian Government.

We present 3-mm observations of the quasar J0015+1842 at z=2.63 with the NOrthern Extended Millimeter Array (NOEMA). Our data reveals molecular gas, traced via a Gaussian CO(3-2) line, with a remarkably large velocity dispersion (FWHM=1010+/-120 km/s) and corresponding to a total molecular mass MH2~(3.4-17)x10^10 Msun, depending on the adopted CO-to-H2 conversion factor alphaCO=(0.8-4.0) Msun (km/s pc^2)^-1. Assuming the 3-mm continuum emission is thermal, we derive a dust mass of the order of Mdust ~5x10^8 Msun. J0015+1842 is located in the molecular gas-rich region in the IR vs CO line luminosity diagram, in-between the main locus of main-sequence and sub-millimetre galaxies and that of most other AGNs targeted so far for CO measurements. While the large velocity dispersion of the CO line suggests a merging system, J0015+1842 is observed to be a regular, only very moderately dust-reddened (Av~0.3-0.4) type-I quasar from its UV-optical spectrum, from which we infer a mass of the super-massive black hole be around MBH~6x10^8 Msun. We suggest that J0015+1842 is observed at a galaxy evolutionary stage where a massive merger has brought significant amounts of gas towards an actively accreting super-massive black hole (quasar). While the host still contains a large amount of dust and molecular gas with high velocity dispersion, the quasar has already cleared the way towards the observer, likely through powerful outflows as recently revealed by optical observations of the same object. High angular resolution observations of this and similar systems} should help determining better the respective importance of evolution and orientation in the appearance of quasars and their host galaxies and have the potential to investigate early feedback and star-formation processes in galaxies in their quasar phases., Comment: 5 pages, 5 figures, accepted for publication in A\&A

Context. The properties of galaxies at redshift z > 6 hold the key to our understanding of the early stages of galaxy evolution and can potentially identify the sources of the ultraviolet radiation that give rise to the epoch of reionisation. The far-infrared cooling line of [C II] at 158 μm is known to be bright and correlate with the star formation rate (SFR) of low-redshift galaxies, and hence is also suggested to be an important tracer of star formation and interstellar medium properties for very high-redshift galaxies. Aims. With the aim to study the interstellar medium properties of gravitationally lensed galaxies at z > 6, we search for [C II] and thermal dust emission in a sample of 52 z ∼ 6 galaxies observed by the ALMA Lensing Cluster Survey. Methods. We perform our analysis using LINESTACKER, stacking both [C II] and continuum emission. The target sample is selected from multiple catalogues, and the sample galaxies have spectroscopic redshift or low-uncertainty photometric redshifts (σz Results. Our analyses find no detection of either [C II] or continuum. An upper limit on L[CII] is derived, implying that [C II] remains marginally consistent for low-SFR z > 6 galaxies but likely is under-luminous compared to the local L[CII]-SFR relationship. We discuss potential biases and possible physical effects that may be the cause of the non-detection. Further, the upper limit on the dust continuum implies that less than half of the star formation is obscured.

We present the CO isotopologue Line Atlas within the Whirpool galaxy Survey (CLAWS) based on an IRAM 30-m large programme which provides a benchmark study of numerous, faint CO isotopologues in the mm-wavelength regime across the full disc of M51 (NGC 5194). The survey's core goal is to use the low-J CO isotopologue lines to constrain CO excitation and chemistry, and therefrom the local physical conditions of the gas. In this survey paper, we describe the CLAWS observing and data reduction strategies. We map the J=1-0 and 2-1 transitions of the CO isotopologues $^{12}$CO,$^{13}$CO, C$^{18}$O and C$^{17}$O, as well as several supplementary lines within the 1 mm and 3 mm window (CN(1-0), CS(2-1), CH$_3$OH(2-1), N$_2$H$^+$(1-0), HC$_3$N(10-9)) at ~1 kpc resolution. A total observation time of 149 h offers unprecedented sensitivity. We use these data to explore several CO isotopologue line ratios in detail, study their radial (and azimuthal) trends and investigate whether changes in line ratios stem from changes in ISM properties such as gas temperatures, densities or chemical abundances. For example, we find negative radial trends for the $^{13}$CO}/$^{12}$CO, C$^{18}$O/$^{12}$CO and C$^{18}$O/$^{13}$CO line ratios in their J=1-0 transitions. We also find variations with local environment, such as higher $^{12}$CO(2-1)/(1-0) or $^{13}$CO/$^{12}$CO(1-0) line ratios in interarm regions compared to spiral arm regions. We propose that these aforementioned variations of CO line ratios are most likely due to a variation of the optical depth, while abundance variations due to selective nucleosynthesis on a galaxy-wide scale could also play a role. We also study the CO spectral line energy distribution (SLED) using archival JCMT $^{12}$CO(3-2) data and find a variation of the SLED shape with local environmental parameters further underlying changes in optical depth, gas temperatures or densities., 29 pages, 22 figures, accepted for publication in A&A

We use the 21 cm emission line data from the DINGO-VLA project to study the atomic hydrogen gas H\,{\textsc i} of the Universe at redshifts $z, Comment: 13 pages, 9 figures, submitted to MNRAS

We present MeerKAT neutral hydrogen (HI) observations of the Fornax A group, that is likely falling into the Fornax cluster for the first time. Our HI image is sensitive to 1.4 x 10$^{19}$ cm$^{-2}$ over 44.1 km s$^{-1}$, where we detect HI in 10 galaxies and a total of 1.12 x 10$^{9}$ Msol of HI in the intra-group medium (IGM). We search for signs of pre-processing in the 12 group galaxies with confirmed optical redshifts that reside within our HI image. There are 9 galaxies that show evidence of pre-processing and we classify the pre-processing status of each galaxy, according to their HI morphology and gas (atomic and molecular) scaling relations. Galaxies yet to experience pre-processing have extended HI disks, a high HI content with a H$_2$-to-HI ratio an order of magnitude lower than the median for their stellar mass. Galaxies currently being pre-processed display HI tails, truncated HI disks with typical gas ratios. Galaxies in the advanced stages of pre-processing are HI deficient. If there is any HI, they have lost their outer HI disk and efficiently converted their HI to H$_2$, resulting in H$_2$-to-HI ratios an order of magnitude higher than the median for their stellar mass. The central, massive galaxy in our group underwent a 10:1 merger 2 Gyr ago, and ejected 6.6 - 11.2 x 10$^{8}$ Msol of HI that we detect as clouds and streams in the IGM, some forming coherent structures up to 220 kpc in length. We also detect giant (100 kpc) ionised hydrogen (H$\alpha$) filaments in the IGM, likely from cool gas being removed (and ionised) from an infalling satellite. The H$\alpha$ filaments are situated within the hot halo of NGC 1316 and some regions contain HI. We speculate that the H$\alpha$ and multiphase gas is supported by magnetic pressure (possibly assisted by the AGN), such that the hot gas can condense and form HI that survives in the hot halo for cosmological timescales., Comment: 18 pages, 9 figured. Accepted for publication in Astronomy and Astrophysics (A&A)

We present the second data release for the HI-MaNGA programme of HI follow-up observations for the SDSS-IV MaNGA survey. This release contains measurements for 3669 unique galaxies, combining 2108 Green Bank Telescope observations with an updated crossmatch of the MaNGA sample with the ALFALFA survey. We combine these data with MaNGA spectroscopic measurements to examine relationships between HI-to-stellar mass ratio (M_HI/M_*) and average ISM/star formation properties probed by optical emission lines. M_HI/M_* is very weakly correlated with the equivalent width of Halpha, implying a loose connection between the instantaneous star formation rate and the HI reservoir, although the link between M_HI/M_* and star formation strengthens when averaged even over only moderate timescales (~30 Myrs). Galaxies with elevated HI depletion times have enhanced [OI]/Halpha and depressed Halpha surface brightness, consistent with more HI residing in a diffuse and/or shock heated phase which is less capable of condensing into molecular clouds. Of all optical lines, M_HI/M_* correlates most strongly with oxygen equivalent width, EW(O), which is likely a result of the existing correlation between M_HI/M_* and gas-phase metallicity. Residuals in the M_HI/M_*-EW(O) relation are again correlated with [OI]/Halpha and Halpha surface brightness, suggesting they are also driven by variations in the fraction of diffuse and/or shock-heated gas. We recover the strong anti-correlation between M_HI/M_* and gas-phase metallicity seen in previous studies. We also find a relationship between M_HI/M_* and [OI]/Halpha, suggesting that higher fractions of diffuse and/or shock-heated gas are more prevalent in gas-rich galaxies., Accepted for publication in MNRAS, 23 pages, 13 figures, catalog available at https://greenbankobservatory.org/science/gbt-surveys/hi-manga/

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiere, We present the joint analysis of Neutral Hydrogen (H I) Intensity Mapping observations with three galaxy samples: the Luminous Red Galaxy (LRG) and Emission Line Galaxy (ELG) samples from the eBOSS survey, and the WiggleZ Dark Energy Survey sample. The H I intensity maps are Green Bank Telescope observations of the redshifted 21cm21cm emission on 100deg2100deg2 covering the redshift range 0.6 < z < 1.0. We process the data by separating and removing the foregrounds present in the radio frequencies with FASTI ICA. We verify the quality of the foreground separation with mock realizations, and construct a transfer function to correct for the effects of foreground removal on the H I signal. We cross-correlate the cleaned H I data with the galaxy samples and study the overall amplitude as well as the scale dependence of the power spectrum. We also qualitatively compare our findings with the predictions by a semianalytical galaxy evolution simulation. The cross-correlations constrain the quantity ΩHIbHIrHI,optΩHIbHIrHI,opt at an effective scale keff, where ΩHIΩHI is the H I density fraction, bHIbHI is the H I bias, and rHI,optrHI,opt the galaxy–hydrogen correlation coefficient, which is dependent on the H I content of the optical galaxy sample. At keff=0.31hMpc−1keff=0.31hMpc−1 we find ΩHIbHIrHI,Wig=[0.58±0.09(stat)±0.05(sys)]×10−3ΩHIbHIrHI,Wig=[0.58±0.09(stat)±0.05(sys)]×10−3 for GBT-WiggleZ, ΩHIbHIrHI,ELG=[0.40±0.09(stat)±0.04(sys)]×10−3ΩHIbHIrHI,ELG=[0.40±0.09(stat)±0.04(sys)]×10−3 for GBT-ELG, and ΩHIbHIrHI,LRG=[0.35±0.08(stat)±0.03(sys)]×10−3ΩHIbHIrHI,LRG=[0.35±0.08(stat)±0.03(sys)]×10−3 for GBT-LRG, at z ≃ 0.8. We also report results at keff=0.24keff=0.24 and keff=0.48hMpc−1keff=0.48hMpc−1⁠. With little information on H I parameters beyond our local Universe, these are amongst the most precise constraints on neutral hydrogen density fluctuations in an underexplored redshift range

We thank the anonymous referee for their helpful comments. This paper makes use of the ALMA data: ALMA #2018.1.00035.L, #2013.1.00999.S, and #2015.1.01425.S. ALMA is a partnership of the ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by the ESO, AUI/NRAO, and NAOJ. K. K. acknowledges support from the Swedish Research Council (2015-05580), and the Knut and Alice Wallenberg Foundation. K. Kohno acknowledges the JSPS KAKENHI Grant Number JP17H06130 and the NAOJ ALMA Scientific Research Grant Number 2017-06B. F.E.B. acknowledges support from ANID grants CATA-Basal AFB-170002, FONDECYT Regular 1190818, 1200495 and Millennium Science Initiative ICN12_009. D. E. acknowledges support from a Beatriz Galindo senior fellowship (BG20/00224) from the Ministry of Science and Innovation. G. E. M. and F. V. acknowledge the Villum Fonden research grant 13160 "Gas to stars, stars to dust: tracing star formation across cosmic time"? and the Cosmic Dawn Center of Excellence funded by the Danish National Research Foundation under then grant No. 140. F. V. acknowledges support from the Carlsberg Foundation Research Grant CF18-0388 "Galaxies: Rise and Death". A.Z. acknowledges support from the Ministry of Science and Technology, Israel., Context. The properties of galaxies at redshift z>6 hold the key to our understanding of the early stages of galaxy evolution and can potentially identify the sources of the ultraviolet radiation that give rise to the epoch of reionisation. The far-infrared cooling line of [C II] at 158 mu m is known to be bright and correlate with the star formation rate (SFR) of low-redshift galaxies, and hence is also suggested to be an important tracer of star formation and interstellar medium properties for very high-redshift galaxies. Aims. With the aim to study the interstellar medium properties of gravitationally lensed galaxies at z>6, we search for [C II] and thermal dust emission in a sample of 52 > 6 galaxies observed by the ALMA Lensing Cluster Survey. Methods. We perform our analysis using LINESTACKER, stacking both [C II] and continuum emission. The target sample is selected from multiple catalogues, and the sample galaxies have spectroscopic redshift or low-uncertainty photometric redshifts (sigma(z)6 galaxies but likely is under-luminous compared to the local L-[CII]-SFR relationship. We discuss potential biases and possible physical effects that may be the cause of the non-detection. Further, the upper limit on the dust continuum implies that less than half of the star formation is obscured., Swedish Research Council, European Commission 2015-05580, Knut & Alice Wallenberg Foundation, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) JP17H06130, NAOJ ALMA Scientific Research Grant 2017-06B, ANID grants CATA-Basal AFB-170002, Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1190818 1200495, Millennium Science Initiative ICN12_009, Beatriz Galindo senior fellowship from the Ministry of Science and Innovation BG20/00224, Villum Fonden research grant 13160, Danmarks Grundforskningsfond 140, Carlsberg Foundation CF18-0388, Ministry of Science, Technology and Space (MOST), Israel

We present the second data release for the H I-MaNGA programme of H I follow-up observations for the SDSS-IV MaNGA survey. This release contains measurements for 3669 unique galaxies, combining 2108 Green Bank Telescope observations with an updated crossmatch of the MaNGA sample with the ALFALFA survey. We combine these data with MaNGA spectroscopic measurements to examine relationships between H I-to-stellar mass ratio (MH I/M∗) and average ISM/star formation properties probed by optical emission lines. MH I/M∗ is very weakly correlated with the equivalent width of H α, implying a loose connection between the instantaneous star formation rate and the H I reservoir, although the link between MH I/M∗ and star formation strengthens when averaged even over only moderate time-scales (∼30 Myr). Galaxies with elevated H I depletion times have enhanced [O I]/H α and depressed H α surface brightness, consistent with more H I residing in a diffuse and/or shock-heated phase that is less capable of condensing into molecular clouds. Of all optical lines, MH I/M∗ correlates most strongly with oxygen equivalent width, EW(O), which is likely a result of the existing correlation between MH I/M∗ and gas-phase metallicity. Residuals in the MH I/M∗−EW(O) relation are again correlated with [O I]/H α and H α surface brightness, suggesting they are also driven by variations in the fraction of diffuse and/or shock-heated gas. We recover the strong anticorrelation between MH I/M∗ and gas-phase metallicity seen in previous studies. We also find a relationship between MH I/M∗ and [O I]6302/H α, suggesting that higher fractions of diffuse and/or shock-heated gas are more prevalent in gas-rich galaxies.

The neutral atomic gas content of galaxies is usually studied in the HI 21 cm emission line of hydrogen. However, as we go to higher redshifts, owing to the weak strength of the transition, we need very deep integrations to detect HI emission. The HI absorption does not suffer from this dependence on distance as long as there is a sufficiently bright radio source to provide the background continuum. However, resolved HI absorption studies of galaxies are rare. We report one such rare study of resolved HI absorption against the radio galaxy 3C 433 at z = 0.101, detected with the Very Large Array. The absorption was known from single-dish observations, but owing to the higher spatial resolution of our data, we find that the absorber is located against the southern lobe of the radio galaxy. The resolved kinematics shows that the absorber has regular kinematics with an HI mass ≤ 3.4*108M for Tspin= 100 K. We also present deep optical continuum observations and Hα observations from the Gran Telescopio CANARIAS (GTC), which reveal that the absorber is likely to be a faint disc galaxy in the same environment as 3C 433, with a stellar mass of 1010 M and a star-formation rate of 0.15 M yr-1 or less. Considering its HI mass, HI column density, stellar mass, and star-formation rate, this galaxy lies well below the main sequence of star forming galaxies. Its HI mass is lower than the galaxies studied in HI emission at z 0.1. Our GTC imaging has revealed, furthermore, interesting alignments between Hα and radio synchrotron emission in the HI companion and in the host galaxy of the active galactic nucleus as well as in the circumgalactic medium in between. This suggests that the shock ionization of gas by the propagating radio source may happen across a scale spanning many tens of kpc. Overall, our work supports the potential of studying the HI content in galaxies via absorption in the case of a fortuitous alignment with an extended radio continuum source. This approach may allow us to trace galaxies with low HI masses which would otherwise be missed by deep HI emission surveys. In conjunction with the deep all-sky optical surveys, the current and forthcoming blind HI surveys with the Square Kilometre Array (SKA) pathfinder facilities will be able to detect many such systems, though they may not be able to resolve the HI absorption spatially. Phase 1 of the SKA, with its sub-arcsecond resolution and high sensitivity, will be all the more able to resolve the absorption in such systems., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

We forecast astrophysical and cosmological parameter constraints from synergies between 21 cm intensity mapping and wide field optical galaxy surveys (both spectroscopic and photometric) over $z \sim 0-3$. We focus on the following survey combinations in this work: (i) a CHIME-like and DESI-like survey in the northern hemisphere, (ii) an LSST-like and SKA I MID-like survey and (ii) a MeerKAT-like and DES-like survey in the southern hemisphere. We work with the $\Lambda$CDM cosmological model having parameters $\{h, \Omega_m, n_s, \Omega_b, \sigma_8\}$, parameters $v_{c,0}$ and $\beta$ representing the cutoff and slope of the HI-halo mass relation in the previously developed HI halo model framework, and a parameter $Q$ that represents the scale dependence of the optical galaxy bias. Using a Fisher forecasting framework, we explore (i) the effects of the HI and galaxy astrophysical uncertainties on the cosmological parameter constraints, assuming priors from the present knowledge of the astrophysics, (ii) the improvements on astrophysical constraints over their current priors in the three configurations considered, (ii) the tightening of the constraints on the parameters relative to the corresponding HI auto-correlation surveys alone., Comment: 9 pages, 5 figures, 2 tables; accepted for publication in MNRAS

We present new HI data of the dwarf galaxy KK 69, obtained with the Giant Metrewave Radio Telescope (GMRT) with a signal-to-noise ratio that almost double previous observations. We carried out a Gaussian spectral decomposition and stacking methods to identify the cold neutral medium (CNM) and the warm neutral medium (WNM) of the HI gas. We found that 30% of the total HI gas, which corresponds to a mass of approx. 10^7 Mo, is in the CNM phase. The distribution of the HI in KK 69 is not symmetric. Our GMRT HI intensity map of KK 69 overlaid onto a Hubble Space Telescope image reveals an offset of approx. 4 kpc between the HI high-density region and the stellar body, indicating it may be a dwarf transitional galaxy. The offset, along with the potential truncation of the HI body, are evidence of interaction with the central group spiral galaxy NGC 2683, indicating the HI gas is being stripped from KK 69. Additionally, we detected extended HI emission of a dwarf galaxy member of the group as well as a possible new galaxy located near the north-eastern part of the NGC 2683 HI disk., 13 pages, 7 figures, accepted for publication in: Astrophysics and Space Science

Studying the nature of various types of supernovae (SNe) is important for our understanding of stellar evolution. Observations of atomic and molecular gas in the host galaxies of gamma-ray bursts (GRBs) and SNe have recently been used to learn about the nature of the explosions themselves and the star formation events during which their progenitors were born. Based on archival data for M74, which previously has not been investigated in the context of SN positions, we report the gas properties in the environment of the broad-lined type Ic (Ic-BL) SN 2002ap and the type II SNe 2003gd, 2013ej, and 2019krl. The SN 2002ap is located at the end of an off-centre, asymmetric, 55 kpc-long HI extension containing 7.5% of the total atomic gas in M74, interpreted as a signature of external gas accretion. It is the fourth known case of an explosion of a presumably massive star located close to a concentration of atomic gas (after GRBs 980425, 060505, and SN 2009bb). It is unlikely that all these associations are random (at a 3sigma significance), so the case of SN 2002ap adds to the evidence that the birth of the progenitors of type Ic-BL SNe and GRBs is connected with the accretion of atomic gas from the intergalactic medium. The HI extension could come from tidally disrupted companions of M74, or be a remnant of a galaxy or a gas cloud that accreted entirely from the intragroup medium. The other (type II) SNe in M74 are located at the outside edge of a spiral arm. This suggests that either their progenitors were born when gas was piling up there or that the SN progenitors moved away from the arm due to their orbital motions. These type II SNe do not seem to be related to gas accretion., A&A, in press, 7 pages, 5 figures, 1 table

Authors: Koribalski, Bärbel S.; Staveley-Smith, L.; Westmeier, T.; Serra, P.; Spekkens, K.; Wong, O. I.; Lee-Waddell, K.; Lagos, C. D. P.; Obreschkow, D.; Ryan-Weber, E. V.; Zwaan, M.; Kilborn, V.; Bekiaris, G.; Bekki, K.; Bigiel, F.; Boselli, A.; Bosma, A.; Catinella, B.; Chauhan, G.; Cluver, M. E. Colless, M.; Courtois, H. M.; Crain, R. A.; de Blok, W. J. G.; Dénes, H.; Duffy, A. R.; Elagali, A.; Fluke, C. J.; For, B. -Q.; Heald, G.; Henning, P. A.; Hess, K. M.; Holwerda, B. W.; Howlett, C.; Jarrett, T.; Jones, D. H.; Jones, M. G.; Józsa, G. I. G.; Jurek, R.; Jütte, E.; Kamphuis, P.; Karachentsev, I.; Kerp, J.; Kleiner, D.; Kraan-Korteweg, R. C.; López-Sánchez, Á. R.; Madrid, J.; Meyer, M.; Mould, J.; Murugeshan, C.; Norris, R. P.; Oh, S. -H.; Oosterloo, T. A.; Popping, A.; Putman, M.; Reynolds, T. N.; Rhee, J.; Robotham, A. S. G.; Ryder, S.; Schröder, A. C.; Shao, Li; Stevens, A. R. H.; Taylor, E. N.; van der Hulst, J. M.; Verdes-Montenegro, L.; Wakker, B. P.; Wang, J.; Whiting, M.; Winkel, B.; Wolf, C., The Widefield ASKAP L-band Legacy All-sky Blind surveY (wallaby) is a next-generation survey of neutral hydrogen (H i) in the Local Universe. It uses the widefield, high-resolution capability of the Australian Square Kilometer Array Pathfinder (ASKAP), a radio interferometer consisting of 36 × 12 -m dishes equipped with Phased-Array Feeds (PAFs), located in an extremely radio-quiet zone in Western Australia. wallaby aims to survey three-quarters of the sky (− 90 < δ< + 30 ) to a redshift of z≲ 0.26 , and generate spectral line image cubes at ∼30 arcsec resolution and ∼1.6 mJy beam per 4 km s channel sensitivity. ASKAP’s instantaneous field of view at 1.4 GHz, delivered by the PAF’s 36 beams, is about 30 sq deg. At an integrated signal-to-noise ratio of five, wallaby is expected to detect around half a million galaxies with a mean redshift of z∼ 0.05 (∼200 Mpc). The scientific goals of wallaby include: (a) a census of gas-rich galaxies in the vicinity of the Local Group; (b) a study of the H i properties of galaxies, groups and clusters, in particular the influence of the environment on galaxy evolution; and (c) the refinement of cosmological parameters using the spatial and redshift distribution of low-bias gas-rich galaxies. For context we provide an overview of recent and planned large-scale H i surveys. Combined with existing and new multi-wavelength sky surveys, wallaby will enable an exciting new generation of panchromatic studies of the Local Universe. — First results from the wallaby pilot survey are revealed, with initial data products publicly available in the CSIRO ASKAP Science Data Archive (CASDA). © 2020, Springer Nature B.V., The Australian SKA Pathfinder (ASKAP) is part of the Australia Telescope National Facility (ATNF) which is managed by CSIRO. Operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy (NCRIS). ASKAP uses the resources of the Pawsey Supercomputing Centre. Establishment of ASKAP, the Murchison Radio-astronomy Observatory (MRO) and the Pawsey Supercomputing Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. We acknowledge the Wajarri Yamatji as the traditional owners of the Observatory site. FB and DK acknowledge funding from the European Union's Horizon 2020 research and innovation programme; grant agreement No 726384 (FB) and No 679627 (DK). MEC is a recipient of an Australian Research Council Future Fellowship (project number FT170100273) funded by the Australian Government. RKK acknowledges the South African Research Chairs Initiative of the Department of Science and Innovation. RKK and GIGJ acknowledge the South African National Research Foundation for their support. MGJ and LVM acknowledge support from the grants AYA2015-65973-C3-1-R (MINECO/FEDER, UE) and RTI2018-096228-B-C31 (MICIU/FEDER, EU), as well as from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-20170709). MGJ is supported by a Juan de la Cierva formacion fellowship (FJCI-2016-29685). PK is partially supported by the BMBF project 05A17PC2 for D-MeerKAT. DO is a recipient of an Australian Research Council Future Fellowship (FT190100083) funded by the Australian Government. KS acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC). JMvdH acknowledges support from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement nr. 291531. Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013.

Using mid-infrared star formation rate and stellar mass indicators in WISE (Wide-field Infrared Survey Explorer), we construct and contrast the relation between star formation rate and stellar mass for isolated and paired galaxies. Our samples comprise a selection of AMIGA (Analysis of the interstellar Medium in Isolated GAlaxies; isolated galaxies) and pairs of ALFALFA (Arecibo Legacy Fast ALFA) galaxies with H I detections such that we can examine the relationship between H I content (gas fraction, H I deficiency) and galaxy location on the main sequence (MS) in these two contrasting environments. We derive for the first time an H I scaling relation for isolated galaxies using WISE stellar masses, and thereby establish a baseline predictor of H I content that can be used to assess the impact of environment on H I content when compared with samples of galaxies in different environments. We use this updated relation to determine the H I deficiency of both our paired and isolated galaxies. Across all the quantities examined as a function of environment in this work (MS location, gas fraction, and H I deficiency), the AMIGA sample of isolated galaxies is found to have the lower dispersion: σ AMIGA = 0.37 versus σ PAIRS = 0.55 on the MS, σ AMIGA = 0.44 versus σ PAIRS = 0.54 in gas fraction, and σ AMIGA = 0.28 versus σ PAIRS = 0.34 in H I deficiency. We also note fewer isolated quiescent galaxies, 3 (0.6 per cent), compared to 12 (2.3 per cent) quiescent pair members. Our results suggest the differences in scatter measured between our samples are environment driven. Galaxies in isolation behave relatively predictably, and galaxies in more densely populated environments adopt a more stochastic behaviour, across a broad range of quantities. © 2020 The Author(s), This work is based on the research supported in part by the National Research Foundation of South Africa (Grant Numbers UID: 101099 and 111745). JB additionally acknowledges support from the DST-NRF Professional Development Programme (PDP), and the University of Cape Town. MEC is a recipient of an Australian Research Council Future Fellowship (project number FT170100273) funded by the Australian Government. THJ acknowledges funding from the National Research Foundation under the Research Career Advancement and South African Research Chair Initiative programmes, respectively. We acknowledge the work of the entire ALFALFA team for observing, flagging, and performing signal extraction. MGJ is supported by a Juan de la Cierva formaci?n fellowship (FJCI-2016-29685) from the Spanish Ministerio de Ciencia, Innovaci?n y Universidades (MCIU). MGJ also acknowledges support from the grants AYA2015-65973-C3-1- R (MINECO/FEDER, UE) and RTI2018-096228-BC31 (MCIU). This work has been supported by the State Agency for Research of the Spanish MCIU through the 'Centro de Excelencia Severo Ochoa' award to the Instituto de Astrof?sica de Andaluc?a (SEV-2017-0709). This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This work also utilizes data from Arecibo Legacy Fast ALFA (ALFALFA) survey data set obtained with the Arecibo L-band Feed Array (ALFA) on the Arecibo 305-m telescope. Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under Cooperative Agreement with the U.S. National Science Foundation. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/. In addition, we make use of data from the Sloan Digital Sky Survey (SDSS DR7). The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington

Context. Galaxies that hosted many core-collapse supernova (SN) explosions can be used to study the conditions necessary for the formation of massive stars. NGC 2770 was dubbed an SN factory because it hosted four core-collapse SNe in 20 years (three type Ib and one type IIn). Its star formation rate (SFR) was reported to not be enhanced and, therefore, not compatible with such a high SN rate. Aims. We aim to explain the high SN rate of NGC 2770. Methods. We used archival HI line data for NGC 2770 and reinterpreted the Hα and optical continuum data. Results. Even though the continuum-based SFR indicators do not yield high values, the dust-corrected Hα luminosity implies a high SFR, consistent with the high SN rate. Such a disparity between the SFR estimators is an indication of recently enhanced star formation activity because the continuum indicators trace long timescales of the order of 100 Myr, unlike the line indicators, which trace timescales of the order of 10 Myr. Hence, the unique feature of NGC 2770 compared to other galaxies is the fact that it was observed very shortly after the enhancement of the SFR. It also has high dust extinction, E(B - V) above 1 mag. We provide support for the hypothesis that the increased SFR in NGC 2770 is due to the interaction with its companion galaxies. We report an HI bridge between NGC 2770 and its closest companion and the existence of a total of four companions within 100 kpc (one identified for the first time). There are no clear HI concentrations close to the positions of SNe in NGC 2770 such as those detected for hosts of gamma-ray bursts (GRBs) and broad-lined SNe type Ic (IcBL). This suggests that the progenitors of type Ib SNe are not born out of recently accreted atomic gas, as was suggested for GRB and IcBL SN progenitors. © ESO 2020., M.J.M. acknowledges the support of the National Science Centre, Poland through the SONATA BIS grant 2018/30/E/ST9/00208, and of the Polish-U.S. Fulbright Commission. A.d.U.P. and C.C.T. acknowledge the support from Ramon y Cajal fellowships (RyC-2012-09975 and RyC-2012-09984) and from the Spanish research project AYA2017-89384-P. A.L. acknowledges the support of the National Science Centre, Poland through the SONATA BIS grant 2018/30/E/ST9/00208. J.H. was supported by a VILLUM FONDEN Investigator grant (project number 16599). M.P.K. acknowledges support from the First TEAM grant of the Foundation for Polish Science No. POIR.04.04.00-00-5D21/18-00. P.K. is partially supported by the BMBF project 05A17PC2 for D-MeerKAT. The WSRT is operated by the Netherlands Foundation for Research in Astronomy with financial support from the Netherlands Organization for Scientific Research (NWO).

We investigate the relation between the detection of the 11.3 μm polycyclic aromatic hydrocarbon (PAH) feature in the nuclear (∼24-230 pc) regions of 22 nearby Seyfert galaxies and the properties of the cold molecular gas. For the former we use ground-based (0.3-0.6″ resolution) mid-infrared (mid-IR) spectroscopy. The cold molecular gas is traced by ALMA and NOEMA high (0.2-1.1″) angular resolution observations of the CO(2-1) transition. Galaxies with a nuclear detection of the 11.3 μm PAH feature contain more cold molecular gas (median 1.6 × 107 MO ) and have higher column densities (N(H2) = 2 × 1023 cm-2) over the regions sampled by the mid-IR slits than those without a detection. This suggests that molecular gas plays a role in shielding the PAH molecules in the harsh environments of Seyfert nuclei. Choosing the PAH molecule naphthalene as an illustration, we compute its half-life in the nuclear regions of our sample when exposed to 2.5 keV hard X-ray photons. We estimate shorter half-lives for naphthalene in nuclei without a 11.3 μm PAH detection than in those with a detection. The Spitzer/IRS PAH ratios on circumnuclear scales (∼4″ ∼ 0.25-1.3 kpc) are in between model predictions for neutral and partly ionized PAHs. However, Seyfert galaxies in our sample with the highest nuclear H2 column densities are not generally closer to the neutral PAH tracks. This is because in the majority of our sample galaxies, the CO(2-1) emission in the inner ∼4″ is not centrally peaked and in some galaxies traces circumnuclear sites of strong star formation activity. Spatially resolved observations with the MIRI medium-resolution spectrograph on the James Webb Space Telescope will be able to distinguish the effects of an active galactic nucleus (AGN) and star formation on the PAH emission in nearby AGN., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

We present the most precise measurement of the $z = 0$ HI mass function (HIMF) to date based on the final catalogue of the ALFALFA (Arecibo Legacy Fast ALFA) blind HI survey of the nearby Universe. The Schechter function fit has a `knee' mass $\log (M_{*}\,h^{2}_{70}/\mathrm{M_{\odot}}) = 9.94 \pm 0.01 \pm 0.05$, a low-mass slope parameter $\alpha = -1.25 \pm 0.02 \pm 0.1$, and a normalisation $\phi_{*} = (4.5 \pm 0.2 \pm 0.8) \times 10^{-3} \; h^{3}_{70}\,\mathrm{Mpc^{-3}\,dex^{-1}}$, with both random and systematic uncertainties as quoted. Together these give an estimate of the HI content of the $z = 0$ Universe as $\Omega_{\mathrm{HI}} = (3.9 \pm 0.1 \pm 0.6) \times 10^{-4} \, h^{-1}_{70}$ (corrected for HI self-absorption). Our analysis of the uncertainties indicates that the `knee' mass is a cosmologically fair measurement of the $z = 0$ value, with its largest uncertainty originating from the absolute flux calibration, but that the low-mass slope is only representative of the local Universe. We also explore large scale trends in $\alpha$ and $M_{*}$ across the ALFALFA volume. Unlike with the 40 per cent sample, there is now sufficient coverage in both of the survey fields to make an independent determination of the HIMF in each. We find a large discrepancy in the low-mass slope ($\Delta \alpha = 0.14 \pm 0.03$) between the two regions, and argue that this is likely caused by the presence of a deep void in one field and the Virgo cluster in the other. Furthermore, we find that the value of the `knee' mass within the Local Volume appears to be suppressed by $0.18 \pm 0.04$ dex compared to the global ALFALFA value, which explains the lower value measured by the shallower HIPASS. We discuss possible explanations and interpretations of these results and how they can be expanded on with future surveys., Comment: Submitted to MNRAS - 1st revision after comments from referee. 18 pages, 8 figures, 7 tables

We use Atacama Large Millimeter/submillimeter Array (ALMA) observations of H30$\alpha$ (231.90 GHz) emission from the low metallicity dwarf galaxy NGC 5253 to measure the star formation rate (SFR) within the galaxy and to test the reliability of SFRs derived from other commonly-used metrics. The H30$\alpha$ emission, which originates mainly from the central starburst, yields a photoionizing photon production rate of (1.9$\pm$0.3)$\times$10$^{52}$ s$^{-1}$ and an SFR of 0.087$\pm$0.013 M$_\odot$ yr$^{-1}$ based on conversions that account for the low metallicity of the galaxy and for stellar rotation. Among the other star formation metrics we examined, the SFR calculated from the total infrared flux was statistically equivalent to the values from the H30$\alpha$ data. The SFR based on previously-published versions of the H$\alpha$ flux that were extinction corrected using Pa$\alpha$ and Pa$\beta$ lines were lower than but also statistically similar to the H30$\alpha$ value. The mid-infrared (22 $\mu$m) flux density and the composite star formation tracer based on H$\alpha$ and mid-infrared emission give SFRs that were significantly higher because the dust emission appears unusually hot compared to typical spiral galaxies. Conversely, the 70 and 160 $\mu$m flux densities yielded SFR lower than the H30$\alpha$ value, although the SFRs from the 70 $\mu$m and H30$\alpha$ data were within 1-2$\sigma$ of each other. While further analysis on a broader range of galaxies are needed, these results are instructive of the best and worst methods to use when measuring SFR in low metallicity dwarf galaxies like NGC 5253., Comment: 14 pages, 5 figures, accepted for publication in MNRAS

We use observations of chlorine-bearing species in molecular absorbers at intermediate redshifts to investigate chemical properties and $^{35}$Cl/$^{37}$Cl isotopic ratios in the absorbing sightlines. Chloronium (H$_2$Cl$^+$) is detected along three independent lines of sight in the z=0.89 and z=0.68 molecular absorbers located in front of the lensed quasars PKS 1830-211 and B 0218+357, respectively. Hydrogen chloride (HCl) was observed only toward PKS 1830-211, and is found to behave differently from H$_2$Cl$^+$. It is detected in one line of sight with an abundance ratio [H$_2$Cl$^+$]/[HCl] $\sim 1$, but remains undetected in the other, more diffuse, line of sight, with a ratio [H$_2$Cl$^+$]/[HCl]~$>17$. The absorption profiles of these two chlorine-bearing species are compared to other species and discussed in terms of the physical properties of the absorbing gas. Our findings are consistent with the picture emerging from chemical models where different species trace gas with different molecular hydrogen fraction. The $^{35}$Cl/$^{37}$Cl isotopic ratios are measured in the different lines of sight and are discussed in terms of stellar nucleosynthesis., Accepted for publication in Astronomy & Astrophysics 10 pages, 2 figures

We present the HI-MaNGA programme of HI follow-up for the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. MaNGA, which is part of the Fourth phase of the Sloan Digital Sky Surveys (SDSS-IV), is in the process of obtaining integral field unit (IFU) spectroscopy for a sample of ~10,000 nearby galaxies. We give an overview of the HI 21cm radio follow-up observing plans and progress and present data for the first 331 galaxies observed in the 2016 observing season at the Robert C. Bryd Green Bank Telescope (GBT). We also provide a cross match of the current MaNGA (DR15) sample with publicly available HI data from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey. The addition of HI data to the MaNGA data set will strengthen the survey's ability to address several of its key science goals that relate to the gas content of galaxies, while also increasing the legacy of this survey for all extragalactic science., 11 pages, 7 figures. MNRAS accepted version

Analysing the quantified HI profile asymmetries of galaxies in different environments, we explore not only the prevalence of asymmetry in HI profiles, but also the possibility of using HI profile asymmetries to trace merger activity. We construct close pair and isolated galaxy catalogues of HI profiles from the Arecibo Legacy Fast ALFA (ALFALFA) survey, and using a simple HI flux ratio, quantify and compare the profile asymmetries between the two catalogues. In this way, we investigate the popular proposition that merger activity causes HI profiles to become asymmetric, and thereby probe the role of mergers in galaxy evolution. We find small but significant differences between the asymmetry distributions of the two samples, indicating that merger activity does indeed enhance asymmetry in the global HI profile., Comment: 14 pages, 10 figures

We report Giant Metrewave Radio Telescope (GMRT) , Very Large Telescope (VLT) and Spitzer Space Telescope observations of ESO 184$-$G82, the host galaxy of GRB 980425/SN 1998bw, that yield evidence of a companion dwarf galaxy at a projected distance of 13 kpc. The companion, hereafter GALJ193510-524947, is a gas-rich, star-forming galaxy with a star formation rate of $\rm0.004\,M_{\odot}\, yr^{-1}$, a gas mass of $10^{7.1\pm0.1} M_{\odot}$, and a stellar mass of $10^{7.0\pm0.3} M_{\odot}$. The interaction between ESO 184$-$G82 and GALJ193510-524947 is evident from the extended gaseous structure between the two galaxies in the GMRT HI 21 cm map. We find a ring of high column density HI gas, passing through the actively star forming regions of ESO 184$-$G82 and the GRB location. This ring lends support to the picture in which ESO 184$-$G82 is interacting with GALJ193510-524947. The massive stars in GALJ193510-524947 have similar ages to those in star-forming regions in ESO 184$-$G82, also suggesting that the interaction may have triggered star formation in both galaxies. The gas and star formation properties of ESO 184$-$G82 favour a head-on collision with GALJ193510-524947 rather than a classical tidal interaction. We perform state-of-the art simulations of dwarf--dwarf mergers and confirm that the observed properties of ESO 184$-$G82 can be reproduced by collision with a small companion galaxy. This is a very clear case of interaction in a gamma ray burst host galaxy, and of interaction-driven star formation giving rise to a gamma ray burst in a dense environment., Accepted for publication in MNRAS. For the definitive version visit 'https://academic.oup.com/mnras'

Context. Unusual stellar explosions represent an opportunity to learn about both stellar and galaxy evolution. Mapping the atomic gas in host galaxies of such transients can lead to an understanding of the conditions that trigger them. Aims. We provide resolved atomic gas observations of the host galaxy, CGCG137-068, of the unusual and poorly understood transient AT 2018cow, which we obtained in searching for clues to understand its nature. We test whether it is consistent with a recent inflow of atomic gas from the intergalactic medium, as suggested for host galaxies of gamma-ray bursts (GRBs) and some supernovae (SNe). Methods. We observed the HI hyperfine structure line of the AT 2018cow host with the Giant Metrewave Radio Telescope. Results. There is no unusual atomic gas concentration near the position of AT 2018cow. The gas distribution is much more regular than the distributions of GRB/SN hosts. The AT 2018cow host has an atomic gas mass lower by 0.24 dex than predicted from its star formation rate (SFR) and is at the lower edge of the galaxy main sequence. In the continuum we detected the emission of AT 2018cow and of a star-forming region in the north-eastern part of the bar (away from AT 2018cow). This region hosts a third of the galaxy's SFR. Conclusions. The absence of atomic gas concentration close to AT 2018cow, along with a normal SFR and regular HI velocity field, sets CGCG137-068 apart from GRB/SN hosts studied in HI. The environment of AT 2018cow therefore suggests that its progenitor may not have been a massive star. Our findings are consistent with an origin of the transient that does not require a connection between its progenitor and gas concentration or inflow: an exploding low-mass star, a tidal disruption event, a merger of white dwarfs, or a merger between a neutron star and a giant star. We interpret the recently reported atomic gas ring in CGCG 137-068 as a result of internal processes connected with gravitational resonances caused by the bar.© ESO 2019., M.J.M. acknowledges the support of the National Science Centre, Poland, through the POLONEZ grant 2015/19/P/ST9/04010 and SONATA BIS grant 2018/30/E/ST9/00208; this project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 665778. P.K. is supported by the BMBF project 05A17PC2 for D-MeerKAT J.H. was supported by a VILLUM FONDEN Investigator grant (project number 16599). D.A.K. acknowledges support from the Juan de la Cierva Incorporación fellowship IJCI-2015-26153. A.d.U.P. and C.C.T. acknowledge support from Ramón y Cajal fellowships (RyC-2012-09975 and RyC-2012-09984). D.A.K., A.d.U.P., and C.C.T. acknowledge support from the Spanish research project AYA2017-89384-P. L.K.H. acknowledges funding from the INAF PRIN-SKA program 1.05.01.88.04. The Cosmic Dawn Center is funded by the DNRF. R.L. acknowledges support from the grant EMR/2016/007127 from the Dept. of Science and Technology, India. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 679627; project name FORNAX; PI Paolo Serra).

Hickson Compact Group (HCG) 16 is a prototypical compact group of galaxies in an intermediate stage of the previously proposed evolutionary sequence, where its galaxies are losing gas to the intra-group medium (IGrM). The group hosts galaxies that are H I-normal, H I-poor, and centrally active with both AGNs and starbursts, in addition to a likely new member and a H I tidal feature of similar to 160 kpc in length. Despite being a well-studied group at all wavelengths, no previous study of HCG16 has focused on its extraordinary H I component. Aims. The characteristics of HCG16 make it an ideal case study for exploring which processes are likely to dominate the late stages of evolution in compact groups, and ultimately determine their end states. In order to build a coherent picture of the evolution of this group we make use of the multi-wavelength data available, but focus particularly on H I as a tracer of interactions and evolutionary phase. Methods. We reprocess archival VLA L-band observations of HCG16 using the multi-scale CLEAN algorithm to accurately recover diffuse features. Tidal features and galaxies are separated in three dimensions using the SlicerAstro package. The H I deficiency of the separated galaxies is assessed against the benchmark of recent scaling relations of isolated galaxies. This work has been performed with particular attention to reproducibility and is accompanied by a complete workflow to reproduce all the final data products, figures, and results. Results. Despite the clear disruption of the H I component of HCG16 we find that it is not globally H I deficient, even though HCG16a and b have lost the majority of their H I and almost 50% of the group's H I is in the IGrM. The H I content of HCG16d shows highly disturbed kinematics, with only a marginal velocity gradient that is almost perpendicular to its optical major axis. The tail of similar to 160 kpc in length extending towards the southeast appears to be part of an even larger structure which spatially and kinematically connects NGC848 to the northwest corner of the group. Conclusions. This study indicates that in the recent past (similar to 1 Gyr) galaxies HCG16a and b likely underwent major interactions that unbound gas without triggering significant star formation. This gas was then swept away by a close, high-speed encounter with NGC848. The starburst events HCG16c and d, likely initiated by their mutual interaction, triggered galactic winds which, in the case of HCG16d, appear to have disrupted its H I reservoir. The tidal features still connected to all these galaxies indicate that more H I will soon be lost to the IGrM, while that which remains in the discs will likely be consumed by star-formation episodes triggered by their ongoing interaction. This is expected to result in a collection of gas-poor galaxies embedded in a diffuse H I structure, which will gradually (over several Gyr) be evaporated by the UV background, resembling the final stage of the evolutionary model of compact groups., MGJ is supported by a Juan de la Cierva formacion fellowship. We also acknowledge support from the grants AYA2015-65973-C3-1-R and RTI2018-096228-B-C31 (MINECO/FEDER, UE). This work has been supported by the Spanish Science Ministry >Centro de Excelencia Severo Ochoa> program under grant SEV-2017-0709. MGJ wishes to thank B. Koribalski, K. Lee-Waddell, and S. Cazzoli for helpful discussions. We also thank the referee for his thorough comments which helped to improve this paper. This project used archival data from the VLA. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaboration (full acknowledgement at legacysurvey.org/acknowledgment). This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We also acknowledge the use of the HyperLeda database (Makarov et al. 2014). This research made use of APLpy, an open-source plotting package for Python (Robitaille & Bressert 2012; Robitaille 2019), astropy (Astropy Collaboration 2013, 2018), Aladin (Bonnarel et al. 2000), mayavi (Ramachandran & Varoquaux 2011), and SAOImageDS9 (Joye & Mandel 2003).

Active galactic nuclei play a crucial role in the accretion and ejection of gas in galaxies. Although their outflows are well studied, finding direct evidence of accretion has proved very difficult and has so far been done for very few sources. A promising way to study the significance of cold accretion is by observing the absorption of an active galactic nucleus's extremely bright radio emission by the cold gas lying along the line-of-sight. As such, we present ALMA CO(1-0) and CO(2-1) observations of the Hydra-A brightest cluster galaxy (z=0.054) which reveal the existence of cold, molecular gas clouds along the line-of-sight to the galaxy's extremely bright and compact mm-continuum source. They have apparent motions relative to the central supermassive black hole of between -43 and -4 km s$^{-1}$ and are most likely moving along stable, low ellipticity orbits. The identified clouds form part of a $\sim$$10^{9}$ $\text{M}_{\odot}$, approximately edge-on disc of cold molecular gas. With peak CO(2-1) optical depths of $\tau$=0.88 $^{+0.06}_{-0.06}$, they include the narrowest and by far the deepest absorption of this type which has been observed to date in a brightest cluster galaxy. By comparing the relative strengths of the lines for the most strongly absorbing region, we are able to estimate a gas temperature of $42^{+25}_{-11}$ K and line-of-sight column densities of $N_{CO}=2^{+3}_{-1}\times 10 ^{17} cm^{-2}$ and $N_{ H_{2} }=7^{+10}_{-4}\times 10 ^{20} cm^{-2}$., Comment: 11 pages, 8 figures, accepted to MNRAS

We report a multi-objective campaign of targeted 21 cm H i line observations of sources selected from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey and galaxies identified by their morphological and photometric properties in the Sloan Digital Sky Survey. The aims of this program have been (1) to confirm the reality of some ALFALFA sources whose enigmatic nature suggest additional multiwavelength observations; (2) to probe the low signal-to-noise ratio (S/N) regime, below the ALFALFA reliability limit; and (3) to explore the feasibility of using optical morphology, color, and surface brightness to identify gas-rich objects in the region of the Pisces-Perseus Supercluster (PPS) whose H i fluxes are below the ALFALFA sensitivity limit at that distance. As expected, the reliability of ALFALFA detections depends strongly on the S/N of the H i line signal and its coincidence with a probable stellar counterpart identified by its optical properties, suggestive of ongoing star formation. The identification of low-mass, star-forming populations enables targeted H i line observations to detect galaxies with H i line fluxes below the ALFALFA sensitivity limits in fixed local volumes (D < 100 Mpc). The method explored here serves as the basis for extending the sample of gas-bearing objects as part of the ongoing Arecibo Pisces-Perseus Supercluster Survey (APPSS). © 2019. The American Astronomical Society. All rights reserved., This work has been supported by NSF grants AST-1211005, AST-1637339, and AST-1637271. R.G., M.P.H., L.L., and M.G.J. acknowledge support from NSF grants AST-1107390 and AST-1714828 and by grants from the Brinson Foundation. M.G.J. acknowledges support from the grant AYA2015-65973-C3-1-R (MINECO/FEDER, UE).

We present IRAM-30m Telescope $^{12}$CO and $^{13}$CO observations of a sample of 55 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in the local universe. This sample is a subset of the Great Observatory All-Sky LIRG Survey (GOALS), for which we use ancillary multi-wavelength data to better understand their interstellar medium and star formation properties. Fifty-three (96%) of the galaxies are detected in $^{12}$CO, and 29 (52%) are also detected in $^{13}$CO above a 3$\sigma$ level. The median full width at zero intensity (FWZI) velocity of the CO line emission is 661km s$^{-1}$, and $\sim$54% of the galaxies show a multi-peak CO profile. Herschel photometric data is used to construct the far-IR spectral energy distribution of each galaxy, which are fit with a modified blackbody model that allows us to derive dust temperatures and masses, and infrared luminosities. We make the assumption that the gas-to-dust mass ratio of (U)LIRGs is comparable to local spiral galaxies with a similar stellar mass (i.e., gas/dust of mergers is comparable to their progenitors) to derive a CO-to-H$_2$ conversion factor of $\langle\alpha\rangle=1.8^{+1.3}_{-0.8}M_\odot$(K km s$^{-1}$pc$^{2}$)$^{-1}$; such a value is comparable to that derived for (U)LIRGs based on dynamical mass arguments. We derive gas depletion times of $400-600$Myr for the (U)LIRGs, compared to the 1.3Gyr for local spiral galaxies. Finally, we re-examine the relationship between the $^{12}$CO/$^{13}$CO ratio and dust temperature, confirming a transition to elevated ratios in warmer systems., Comment: 32 pages, 10 figures. Accepted for publication in Astronomy & Astrophysics

Context. Asymmetries in atomic hydrogen (HI) in galaxies are often caused by the interaction with close companions, making isolated galaxies an ideal framework to study secular evolution. The AMIGA project has demonstrated that isolated galaxies show the lowest level of asymmetry in their HI integrated profiles compared to even field galaxies, yet some present significant asymmetries. CIG 96 (NGC 864) is a representative case reaching a 16% level. Aims. Our aim is to investigate the HI asymmetries of the spiral galaxy CIG 96 and what processes have triggered the star-forming regions observed in the XUV pseudo-ring. Methods. We performed deep optical observations at CAHA1.23m, CAHA2.2m and VST (OmegaCAM wide-field camera) telescopes. We reach surface brightness (SB) limits of μ = 27.5 mag arcsec (Cousins R) and μ = 28.7 mag arcsec (SDSS r) that show the XUV pseudo-ring of the galaxy in detail. Additionally, a wavelet filtering of the HI data cube from our deep observations with VLA/EVLA telescope allowed us to reach a column density of N = 8.9 × 10 cm (5σ) (28″ × 28″ beam), lower than in any isolated galaxy. Results. We confirm that the HI of CIG 96 extends farther than 4 × r in all directions. Furthermore, we detect for the first time two gaseous structures (∼10 M) in the outskirts. The SDSS g-r colour index image from CAHA1.23m shows extremely blue colours in certain regions of the pseudo-ring where N > 8.5 × 10 cm, whereas the rest show red colours. Galactic cirrus contaminate the field, setting an unavoidable detection limit at 28.5 mag arcsec (SDSS r). Conclusions. At the current SB and N levels, we detect no stellar link within 1° × 1° or gaseous link within 40′ × 40′ between CIG 96 and any companion. The isolation criteria rule out interactions with other similar-sized galaxies for at least ∼2.7 Gyr. Using existing stellar evolution models, the age of the pseudo-ring is estimated at 1 Gyr or older. Undetected previously accreted companions and cold gas accretion remain as the main hypothesis to explain the optical pseudo-ring and HI features of CIG 96.© 2018 ESO., P.R.M. is funded by the project AMIGA4GAS project and the FPI Grant AYA2011-30491-C02-01 by the Ministry of Economy and Competitiveness of Spain. P.R.M., L.V.M., J.B.H., M.J., M.F.L., S.S.E., J.G.S. acknowledge support from the grant AYA2015-65973-C3-1-R (MINECO/FEDER, UE). J.I.P. acknowledges financial support from the Spanish Ministerio de Economia y Competitividad under grant AYA2013-47742-C4-1-P, and from Junta de Andalucia Excellence Project PEX2011-FQM-7058.This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration.

We present Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY) early science results from the Australian Square Kilometre Array Pathfinder (ASKAP) observations of the NGC 7162 galaxy group. We use archival HIPASS and Australia Telescope Compact Array (ATCA) observations of this group to validate the new ASKAP data and the data reduction pipeline ASKAPsoft. We detect six galaxies in the neutral hydrogen (HI) 21-cm line, expanding the NGC 7162 group membership from four to seven galaxies. Two of the new detections are also the first HI detections of the dwarf galaxies, AM 2159-434 and GALEXASC J220338.65-431128.7, for which we have measured velocities of $cz=2558$ and $cz=2727$ km s$^{-1}$, respectively. We confirm that there is extended HI emission around NGC 7162 possibly due to past interactions in the group as indicated by the $40^{\circ}$ offset between the kinematic and morphological major axes for NGC 7162A, and its HI richness. Taking advantage of the increased resolution (factor of $\sim1.5$) of the ASKAP data over archival ATCA observations, we fit a tilted ring model and use envelope tracing to determine the galaxies' rotation curves. Using these we estimate the dynamical masses and find, as expected, high dark matter fractions of $f_{\mathrm{DM}}\sim0.81-0.95$ for all group members. The ASKAP data are publicly available., 20 pages, 11 figures, accepted for publication in MNRAS

We describe the CO Luminosity Density at High-z (COLDz) survey, the first spectral line deep field targeting CO(1-0) emission from galaxies at $z=1.95-2.85$ and CO(2-1) at $z=4.91-6.70$. The main goal of COLDz is to constrain the cosmic density of molecular gas at the peak epoch of cosmic star formation. By targeting both a wide ($\sim$51 arcmin$^2$) and a deep area ($\sim$9 arcmin$^2$), the survey is designed to robustly constrain the bright end and the characteristic luminosity of the CO(1-0) luminosity function. An extensive analysis of the reliability of our line candidates, and new techniques provide detailed completeness and statistical corrections as necessary to determine the best constraints to date on the CO luminosity function. Our blind search for CO(1-0) uniformly selects starbursts and massive Main Sequence galaxies based on their cold molecular gas masses. Our search also detects CO(2-1) line emission from optically dark, dusty star-forming galaxies at $z>5$. We find a range of spatial sizes for the CO-traced gas reservoirs up to $\sim40$ kpc, suggesting that spatially extended cold molecular gas reservoirs may be common in massive, gas-rich galaxies at $z\sim2$. Through CO line stacking, we constrain the gas mass fraction in previously known typical star-forming galaxies at $z=2$-3. The stacked CO detection suggests lower molecular gas mass fractions than expected for massive Main Sequence galaxies by a factor of $\sim3-6$. We find total CO line brightness at $\sim34\,$GHz of $0.45\pm0.2\,��$K, which constrains future line intensity mapping and CMB experiments., 53 pages, 22 figures, 8 tables, ApJ in press. Full resolution images and publicly available data may be found on the survey webpage at coldz.astro.cornell.edu

We have measured the relationships between HI mass, stellar mass and star formation rate using the HI Parkes All Sky-Survey Catalogue (HICAT) and the Wide-field Infrared Survey Explorer (WISE). Of the 3,513 HICAT sources, we find 3.4 micron counterparts for 2,896 sources (80%) and provide new WISE matched aperture photometry for these galaxies. For our principal sample of spiral galaxies with W1 $\le$ 10 mag and z $\le$ 0.01, we identify HI detections for 93% of the sample. We measure lower HI-stellar mass relationships that HI selected samples that do not include spiral galaxies with little HI gas. Our observations of the spiral sample show that HI mass increases with stellar mass with a power-law index 0.35; however, this value is dependent on T-type, which affects both the median and the dispersion of HI mass. We also observe an upper limit on the HI gas fraction, which is consistent with a halo spin parameter model. We measure the star formation efficiency of spiral galaxies to be constant 10$^{-9.57}$ yr$^{-1}$ $\pm$ 0.4 dex for 2.5 orders of magnitude in stellar mass, despite the higher stellar mass spiral showing evidence of quenched star formation., 20 pages, 13 figures; accepted for publication by ApJ

We present a 3x3 degrees, 105-pointing, high-resolution neutral hydrogen (HI) mosaic of the M81 galaxy triplet (including the galaxies M81, M82 and NGC 3077, as well as dwarf galaxy NGC 2976) obtained with the Very Large Array (VLA) C and D arrays. This uniformly covers the entire area and velocity range of the triplet with a resolution of ~20'' or ~420 pc. The data reveal many small-scale anomalous velocity features highlighting the complexity of the interacting M81 triplet. We compare our data with Green Bank Telescope (GBT) observations of the same area. This provides evidence for a substantial reservoir of low-column density gas in the northern part of the triplet, probably associated with M82. Such a reservoir is not found in the southern part. We report a number of kpc-sized low-mass HI clouds with HI masses of a few times 10^6 Msun. Their dynamical masses are much larger than their baryonic masses, which could indicate the presence of dark matter if the clouds are rotationally supported. However, due to their spatial and kinematical association with HI tidal features, it is more likely that the velocity widths indicate tidal effects or streaming motions. We do not find any clouds not associated with tidal features down to an HI mass limit of a few times 10^4 Msun. We compare the HI column densities with resolved stellar density maps and find a star formation threshold around 3-6 10^20 cm-2$. We find that extreme velocity dispersions can be explained by a superposition of multiple components along the line of sight near M81 as well as winds or outflows around M82. The velocity dispersions found are high enough that these processes could explain the linewidths of Damped-Lyman-alpha absorbers observed at high redshift., Accepted for publication in The Astronomical Journal. Full-resolution PDF available at http://www.astron.nl/~blok/M81data/m81data.pdf. Data can be downloaded from http://www.astron.nl/~blok/M81data

We present HI synthesis imaging of the giant elliptical galaxy IC 1459 and its surroundings with the Australia Telescope Compact Array. Our search for extended HI emission revealed a large complex of HI clouds near IC 1459, likely to be the debris from tidal interactions with neighbouring galaxies. The total HI mass (~109M⊙) in the detected clouds spans 250 kpc from the north-east of the gas-rich spiral NGC 7418A to the south-east of IC 1459. The extent and mass of the HI debris, which shows rather irregular morphology and kinematics, are similar to those in other nearby groups. Together with HI clouds recently detected near two other IC 1459 group members, namely IC 5270 and NGC 7418, using phased-array feeds on the Australian Square Kilometre Array Pathfinder, the detected debris make up a significant fraction of the group's intergalactic medium., Instituto Argentino de Radioastronomía, Facultad de Ciencias Astronómicas y Geofísicas

We present the catalog of ∼31,500 extragalactic H i line sources detected by the completed Arecibo Legacy Fast ALFA (ALFALFA) survey out to z < 0.06, including both high signal-to-noise ratio (>6.5) detections and ones of lower quality that coincide in both position and recessional velocity with galaxies of known redshift. We review the observing technique, data reduction pipeline, and catalog construction process, focusing on details of particular relevance to understanding the catalog's compiled parameters. We further describe and make available the digital H i line spectra associated with the cataloged sources. In addition to the extragalactic H i line detections, we report nine confirmed OH megamasers (OHMs) and 10 OHM candidates at 0.16 < z < 0.22 whose OH line signals are redshifted into the ALFALFA frequency band. Because of complexities in data collection and processing associated with the use of a feed-horn array on a complex single-dish antenna in the terrestrial radio frequency interference environment, we also present a list of suggestions and caveats for consideration by users of the ALFALFA extragalactic catalog for future scientific investigations.© 2018. The American Astronomical Society. All rights reserved., The authors acknowledge the work of the entire ALFALFA collaboration who have contributed to the many aspects of the survey over the years. The ALFALFA team at Cornell has been supported by NSF grants AST-0607007, AST-1107390, and AST-1714828 and grants from the Brinson Foundation. Participation of the Undergraduate ALFALFA Team has been made possible by NSF grants AST-0724918, AST-0725267, AST-0725380, AST-0902211, AST-0903394, AST-1211005, AST-1637339, AST-1637271, AST-1637299, AST-1637262, and AST-1637276. EAKA is supported by the WISE research program, which is financed by the Netherlands Organisation for Scientific Research (NWO). BRK acknowledges the National Radio Astronomy Observatory (NRAO). The NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. MGJ acknowledges support from grant AYA2015-65973-C3-1-R (MINECO/FEDER, UE). We thank Dmitry Makarov for comments and suggestions on cross-identifications. This work is based on observations made with the Arecibo Observatory. The Arecibo Observatory has been operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968) and in alliance with Ana G. Mendez-Universidad Metropolitana and the Universities Space Research Association. We thank the staff of the Arecibo Observatory, especially Phil Perillat, Ganesh Rajagopalan, Arun Venkataraman, Hector Hernandez, and the telescope operations group for their outstanding support of the ALFALFA survey program. We acknowledge the use of NASA's SkyView facility (http://skyview.gsfc.nasa.gov), located at NASA Goddard Space Flight Center, and the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions. The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation. This research used data from the Sloan Digital Sky Survey. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England.