This paper presents 586 new 21-cm neutral hydrogen line measurements carried out with the FORT receiver of the meridian transit Nancay radiotelescope in the period July 2000 - March 2003. This observational programme is part of a larger project aiming at collecting an exhaustive and magnitude-complete HI extragalactic catalogue for Tully-Fisher applications. It is associated with the building of the MIGALE spectroscopic archive and database. http://klun.obs-nancay.fr, http://http://www.sai.msu.su/migale/
Galaxy evolution is driven to a large extent by interactions and mergers with other galaxies and the gas in galaxies is extremely sensitive to the interactions. One method to measure such interactions uses the quantified morphology of galaxy images. Well-established parameters are Concentration, Asymmetry, Smoothness, Gini and M20 of a galaxy image. Thus far, the application of this technique has mostly been restricted to rest-frame ultraviolet and optical images. However, with the new radio observatories being commissioned [South African Karoo Array Telescope (MeerKAT), Australian SKA Pathfinder (ASKAP), Extended Very Large Array (EVLA), Westerbork Synthesis Radio Telescope/APERture Tile In Focus instrument (WSRT/APERTIF) and ultimately the Square Kilometer Array (SKA)], a new window on the neutral atomic hydrogen gas (HI) morphology of large numbers of galaxies will open up. The quantified morphology of gas discs of spirals can be an alternative indicator of the level and frequency of interaction. The HI in galaxies is typically spatially more extended and more sensitive to low-mass or weak interactions.
We present "The HI Nearby Galaxy Survey (THINGS)," a high spectral (<=5.2km/s) and spatial (~6") resolution survey of HI emission in 34 nearby galaxies obtained using the NRAO Very Large Array (VLA). The overarching scientific goal of THINGS is to investigate fundamental characteristics of the interstellar medium (ISM) related to galaxy morphology, star formation, and mass distribution across the Hubble sequence. Unique characteristics of the THINGS database are the homogeneous sensitivity as well as spatial and velocity resolution of the HI data, which is at the limit of what can be achieved with the VLA for a significant number of galaxies. A sample of 34 objects at distances 2<~D>~15Mpc (resulting in linear resolutions of ~100 to 500pc) are targeted in THINGS, covering a wide range of star formation rates (~10^-3^ to 6M_{sun}_/yr), total HI masses MHI (0.01 to 14x10^9^M_{sun}_), absolute luminosities MB (-11.5 to -21.7mag), and metallicities (7.5 to 9.2 in units of 12+log[O/H]). We describe the setup of the VLA observations, the data reduction procedures, and the creation of the final THINGS data products. We present an atlas of the integrated HI maps, the velocity fields, the second moment (velocity dispersion) maps and individual channel maps of each THINGS galaxy. The THINGS data products are made publicly available through a dedicated webpage (http://www.mpia.de/THINGS). Accompanying THINGS papers (in this issue of the Astronomical Journal) address issues such as the small-scale structure of the ISM, the (dark) matter distribution in THINGS galaxies, and the processes leading to star formation.
As the nearest large spiral galaxy, M 31 provides a unique opportunity to study the structure and evolutionary history of this galaxy type in great detail. Among the many observing programs aimed at M 31 are microlensing studies, which require good three-dimensional models of the stellar mass distribution. Possible non-axisymmetric structures like a bar need to be taken into account. Due to M 31's high inclination, the bar is difficult to detect in photometry alone. Therefore, detailed kinematic measurements are needed to constrain the possible existence and position of a bar in M 31. We obtained ~=220 separate fields with the optical integral-field unit spectrograph VIRUS-W, covering the whole bulge region of M 31 and parts of the disk. We derived stellar line-of-sight velocity distributions from the stellar absorption lines, as well as velocity distributions and line fluxes of the emission lines H{beta}, [OIII] and [NI]. Our data supersede any previous study in terms of spatial coverage and spectral resolution. We find several features that are indicative of a bar in the kinematics of the stars, we see intermediate plateaus in the velocity and the velocity dispersion, and correlation between the higher moment h3 and the velocity. The gas kinematics is highly irregular, but is consistent with non-triaxial streaming motions caused by a bar. The morphology of the gas shows a spiral pattern, with seemingly lower inclination than the stellar disk. We also look at the ionization mechanisms of the gas, which happens mostly through shocks and not through starbursts.
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 triggering them. We provide resolved atomic gas observations of the host galaxy, CGCG137-068, of the unusual, poorly-understood transient AT2018cow 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). We observed the HI hyperfine structure line of the AT2018cow host with the Giant Metrewave Radio Telescope. There is no unusual atomic gas concentration near the position of AT2018cow. The gas distribution is much more regular than those of GRB/SN hosts. The AT2018cow host has an atomic gas mass lower by 0.24dex 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 AT2018cow and of a star-forming region in the north-eastern part of the bar (away from AT2018cow). This region hosts a third of the galaxy's SFR. The absence of atomic gas concentration close to AT2018cow, along with a normal SFR and regular HI velocity field, sets CGCG137-068 apart from GRB/SN hosts studied in HI. The environment of AT2018cow 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 CGCG137-068 as a result of internal processes connected with gravitational resonances caused by the bar.
High sensitivity 21-cm HI line observations with an rms noise level of ~0.5mJy were made of 35 spiral galaxies in the Coma Supercluster, using the refurbished Arecibo telescope, leading to detection of 25 objects. These data, combined with the measurements available in the literature, provide the set of HI data for 94% of all late-type galaxies in the Coma Supercluster with an apparent photographic magnitude m_p_<=15.7mag. We confirm that the typical scale of HI deficiency around the Coma cluster is 2Mpc, i.e. one virial radius. Comparing the HI mass function (HIMF) of cluster with non-cluster members of the Coma Supercluster we detected a shortage of high HI mass galaxies among cluster members that can be attributed to the pattern of HI deficiency found in rich clusters.
We report HI-observations of a sample of 43 optically selected galaxies from the Heidelberg-void project. Only emission-line galaxies have been selected. The HI-detection rate was 67%. The observed sample is a mix in late-type morphology objects with a spread in luminosity. They were compared to other samples with similar selection effects and mixtures. The detected galaxies have a high HI content and their M_HI_/L_B_ values are systematically higher than expected from a local field comparison sample. Especially, for the 10 dwarfs in our sample (8.2<=logL_B_<=9.2) which appear to be highly isolated, a mean M_HI_/L_B_=1.8 was derived which is higher than for all comparison samples, including those with the same restricted luminosity range. We discuss a trend in our data between the relative HI-content and the surrounding galaxy density holding from very high densities (Virgo-cluster) to the very isolated objects at the rims of the voids. We also present HI observations of 7 HII-galaxies of the University of Michigan (UM) sample.
Results of HI observations with the 100-m Effelsberg radio telescope are presented for 94 edge-on spiral galaxies from the Revised Flat Galaxy Catalog (Karachentsev et al., 1999, Cat. <VII/219>) and 14 galaxies from the 2MASS-selected Flat Galaxy Catalog (Mitronova et al., 2004, Bull. Spec. Astron. Obs. Russ. Acad. Sci. 57, 5). The HI line fluxes, heliocentric radial velocities and the HI line widths are given for 65 detected galaxies. Their HI profiles are shown as a mosaic. We calculated some global parameters of the galaxies and discuss linear correlations between them. Total (indicative) mass-to-luminosity ratio for the sample galaxies is ranked within 0.4-8.2 with the mean value 3.8 (M_{sun}_/L_{sun}_), and the mean fraction of hydrogen mass is 0.13. For 43 undetected objects their rms noise is also given.
We present H I 21-cm line observations of 543 galaxies at low galactic latitude in the Galactic Anticenter region of the Zone of Avoidance (4h<={alpha}<=8h, 0{deg}=<{delta}=<37{deg}). The sample comprises 147 catalogued objects (from UGC, CGCG, MCG, and IRAS) still missing a redshift measurement and a list of 369 objects selected from an extensive optical compilation of galaxy candidates in this area. The spectra were acquired using the 305-m Arecibo telescope and cover a velocity range from -350 to +13800km/s at a resolution of about 16km/s. 196 galaxies were detected,59 of the catalogued ones and 137 from the optical compilation. The H I derived properties are presented, as is a discussion regarding the redshift distribution in this region. Our data seem to be consistent with a link across the Zone of Avoidance between the Pisces-Perseus supercluster and Abell 569.
We have used the Nancay Radio Telescope to obtain new global HI data for 16 giant low surface brightness (LSB) galaxies. Our targets have optical luminosities and disk scale lengths at the high end for spiral galaxies (L_B_~10^10^L_{sun}_ and h_r_>6kpc for H_0_=75km/s/Mpc), but they have diffuse stellar disks, with mean disk surface brightnesses >1 magnitude fainter than normal giant spirals. Thirteen of the galaxies previously had been detected in HI by other workers, but the published HI observations were either confused, resolved by the telescope beam, of low signal-to-noise, or showed significant discrepancies between different authors. For the other 3 galaxies, no HI data were previously available. Several of the galaxies were resolved by the Nancay 3.6' E-W beam, so global parameters were derived from multiple-point mapping observations. Typical HI masses for our sample are >10^10^M_{sun}_, with M_HI_/L_B_=0.3-1.7 (in solar units). All of the observed galaxies have published optical surface photometry, and we have compiled key optical measurements for these objects from the literature. We frequently find significant variations among physical parameters of giant LSB galaxies reported by various workers.
