- ID:
- ivo://CDS.VizieR/J/MNRAS/383/1519
- Title:
- Abell 1367 HI sources from AGES
- Short Name:
- J/MNRAS/383/1519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 21cm HI line observations of 5x1deg^2^ centred on the local Abell cluster 1367 obtained as part of the Arecibo Galaxy Environment Survey. One hundred sources are detected (79 new HI measurements and 50 new redshifts), more than half belonging to the cluster core and its infalling region. Combining the HI data with Sloan Digital Sky Survey (SDSS) optical imaging, we show that our HI selected sample follows scaling relations similar to the ones usually observed in optically selected samples. Interestingly, all galaxies in our sample appear to have nearly the same baryon fraction independently of their size, surface brightness and luminosity. The most striking difference between HI and optically selected samples resides in their large-scale distribution: whereas optical and X-ray observations trace the cluster core very well, in HI there is almost no evidence of the presence of the cluster. Some implications on the determination of the cluster luminosity function and HI distribution for samples selected at different wavelength are also discussed.
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- ID:
- ivo://CDS.VizieR/J/A+A/632/A78
- Title:
- A case study of the HI content of HCG 16
- Short Name:
- J/A+A/632/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hickson Compact Group (HCG) 16 is a prototypical compact group of galaxies in an intermediate stage of the evolutionary sequence proposed by Verdes-Montenegro et al. (2001A&A...377..812V), where its galaxies are losing gas to the intra-group medium (IGrM). The group hosts galaxies that are HI-normal, HI-poor, centrally active with both AGN and starbursts, as well as a likely new member and a 160kpc long HI tidal feature. Despite being a well-studied group at all wavelengths, no previous study of HCG 16 has focused on its extraordinary HI component. The characteristics of HCG 16 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 HI as a tracer of interactions and evolutionary phase. We reprocess archival VLA L-band observations of HCG 16 using the multi-scale CLEAN algorithm to accurately recover diffuse features. Tidal features and galaxies are separated in 3 dimensions using the SlicerAstro package. The HI 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. Despite the clear disruption of the HI component of HCG 16 we find that it is not globally HI deficient, even though HCG 16a and b have lost the majority of their HI and almost 50% of the group's HI is in the IGrM. The HI content of HCG 16d shows highly disturbed kinematics, with only a marginal velocity gradient that is almost perpendicular to its optical major axis. The ~160kpc long tail extending towards the South-East appears to be part of an even larger structure which spatially and kinematically connects NGC 848 to the North-West corner of the group. This study indicates that in the recent past (1Gyr) galaxies HCG 16a and b likely underwent major interactions that unbound gas without triggering significant star formation. This gas was then swept away by a high speed, close encounter with NGC 848. The starburst events HCG 16c and d, likely initiated by their mutual interaction, have triggered galactic winds which, in the case of HCG 16d, appears to have disrupted its HI reservoir. The tidal features still connected to all these galaxies indicate that more HI 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 on-going interaction. This is expected to result in a collection of gas-poor galaxies embedded in a diffuse HI structure, which will gradually (over several Gyr) be evaporated by the UV background, resembling the final stage of the evolutionary model of compact groups.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/1883
- Title:
- AGES HI sources in NGC 7448
- Short Name:
- J/MNRAS/415/1883
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we describe results from the Arecibo Galaxy Environments Survey (AGES). The survey reaches column densities of ~3x10^18^cm^-2^ and masses of ~10^7^M_{sun}_, over individual regions of order 10deg^2^ in size, out to a maximum velocity of 18000km/s. Each surveyed region is centred on a nearby galaxy, group or cluster, in this instance the NGC 7448 group. Galaxy interactions in the NGC 7448 group reveal themselves through the identification of tidal tails and bridges. We find ~2.5 times more atomic gas in the intergalactic medium than in the group galaxies. We identify five new dwarf galaxies, two of which appear to be members of the NGC 7448 group. This is too small, by roughly an order of magnitude, a number of dwarf galaxies to reconcile observation with theoretical predictions of galaxy formation models. If they had observed this region of the sky in previous wide-area blind HI surveys, HIPASS and ALFALFA, they would have detected only 5 and 43 per cent, respectively, of the galaxies we have detected, missing a large fraction of the atomic gas in this volume.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/2634
- Title:
- AGES HI sources in NGC 7448 field
- Short Name:
- J/MNRAS/443/2634
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present completed observations of the NGC 7448 galaxy group and background volume as part of the blind neutral hydrogen Arecibo Galaxy Environment Survey. Our observations cover a region spanning 5{deg}x4{deg}, over a redshift range of approximately -2000<cz<20000km/s. A total of 334 objects are detected, mostly in three overdensities at cz~7500, cz~9600 and cz~11400km/s. The galaxy density is extremely high (15deg^-2^) and many (~24%) show signs of extended HI emission, including some features as much as 800kpc in projected length. We describe the overall characteristics of this environment: kinematics, typical galaxy colours and mass-to-light ratios, and substructure. To aid in the cataloguing of this data set, we present a new fits viewer (FRELLED: fits Realtime Explorer of Low Latency in Every Dimension). This incorporates interactive source cataloguing tools which increase our source extraction speed by approximately a factor of 50.
- ID:
- ivo://CDS.VizieR/J/ApJ/861/49
- Title:
- ALFALFA extragalactic HI source catalog
- Short Name:
- J/ApJ/861/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of ~31500 extragalactic HI 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 HI line spectra associated with the cataloged sources. In addition to the extragalactic HI 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.
- ID:
- ivo://CDS.VizieR/J/AJ/142/170
- Title:
- ALFALFA survey: the {alpha}.40 HI source catalog
- Short Name:
- J/AJ/142/170
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a current catalog of 21cm HI line sources extracted from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey over ~2800deg^2^ of sky: the {alpha}.40 catalog. Covering 40% of the final survey area, the {alpha}.40 catalog contains 15855 sources in the regions 07h30m<RA<16h30m, +04{deg}<DEC<+16{deg}, and +24{deg}<DEC<+28{deg} and 22h<RA<03h, +14{deg}<DEC<+16{deg}, and +24{deg}<DEC<+32{deg}. Of those, 15041 are certainly extragalactic, yielding a source density of 5.3 galaxies per deg^2^, a factor of 29 improvement over the catalog extracted from the HI Parkes All-Sky Survey. In addition to the source centroid positions, HI line flux densities, recessional velocities, and line widths, the catalog includes the coordinates of the most probable optical counterpart of each HI line detection, and a separate compilation provides a cross-match to identifications given in the photometric and spectroscopic catalogs associated with the Sloan Digital Sky Survey Data Release 7. Fewer than 2% of the extragalactic HI line sources cannot be identified with a feasible optical counterpart; some of those may be rare OH megamasers at 0.16<z<0.25. A detailed analysis is presented of the completeness, width-dependent sensitivity function and bias inherent of the {alpha}.40 catalog. The impact of survey selection, distance errors, current volume coverage, and local large-scale structure on the derivation of the HI mass function is assessed.
- ID:
- ivo://CDS.VizieR/J/AJ/139/2130
- Title:
- ALFA-ZOA precursor observation
- Short Name:
- J/AJ/139/2130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Arecibo L-band Feed Array (ALFA) is being used to conduct a low-Galactic latitude survey, to map the distribution of galaxies and large-scale structures behind the Milky Way through detection of galaxies' neutral hydrogen (HI) 21cm emission. This Zone of Avoidance (ZOA) survey finds new HI galaxies which lie hidden behind the Milky Way, and also provides redshifts for partially obscured galaxies known at other wavelengths. Before the commencement of the full survey, two low-latitude precursor regions were observed, totaling 138deg^2^, with 72 HI galaxies detected. Detections through the inner Galaxy generally have no cataloged counterparts in any other waveband, due to the heavy extinction and stellar confusion. Detections through the outer Galaxy are more likely to have Two Micron All Sky Survey counterparts. We present the results of these precursor observations, including a catalog of the detected galaxies, with their HI parameters.
- ID:
- ivo://CDS.VizieR/J/AJ/158/234
- Title:
- ALFAZOA Shallow Survey galaxy properties
- Short Name:
- J/AJ/158/234
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Arecibo L-band Feed Array Zone of Avoidance (ALFAZOA) Shallow Survey is a blind H I survey of the extragalactic sky behind the northern Milky Way conducted with the ALFA receiver on the 305 m Arecibo Radio Telescope. ALFAZOA Shallow covered 900 square degrees at full sensitivity from 30{deg}=<l=<75{deg} and |b|=<10{deg} and an additional 460 square degrees at limited sensitivity at latitudes up to 20{deg}. It has an rms sensitivity of 5-7 mJy and a velocity resolution of 9-20.6 km/s, and detected 403 galaxies out to a recessional velocity of 12000 km/s, with an angular resolution of 3.4' and a positional accuracy between 0.2' and 1.7'. The survey is complete above an integrated line flux of F_HI_=2.0 Jy km/s for half the survey, and above F_HI_= 2.8 Jy km/s for the other half. Of the ALFAZOA H I detections, 43% have at least one possible optical/near-infrared counterpart in the literature, and an additional 16% have counterparts that only included previous H I measurements. There are fewer counterparts in regions of high extinction and for galaxies with lower H I mass. Comparing the results of the survey to the predictions of Erdogdu et al. (2006MNRAS.373...45E), and using their nomenclature, ALFAZOA confirms the position and extent in the ZOA of the C7, C{zeta}, Pegasus, Corona Borealis, and Delphinus structures, but not of the Cygnus void. Two new structures are identified, both connected to the C7 overdensity; one extends to 35{deg}, and the other crosses the ZOA.
- ID:
- ivo://CDS.VizieR/J/A+A/532/A117
- Title:
- AMIGA VIII. Flux ratio asymmetry parameter
- Short Name:
- J/A+A/532/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measures of the HI properties of a galaxy are among the most sensitive interaction diagnostic at our disposal. We report here on a study of HI profile asymmetries (e.g., lopsidedness) in a sample of some of the most isolated galaxies in the local Universe. This presents us with an excellent opportunity to quantify the range of intrinsic HI asymmetries in galaxies (i.e., those not induced by the environment) and provides us with a zero-point calibration for evaluating these measurements in less isolated samples. We aim to characterize the HI profile asymmetries in a sample of isolated galaxies and search for correlations between HI asymmetry and their environments, as well as their optical and far infrared (FIR) properties. We use high signal-to-noise global HI profiles for galaxies in the AMIGA project (Analysis of the Interstellar Medium of Isolated GAlaxies, http://amiga.iaa.es). We restrict our study to N=166 galaxies (out of 312) with accurate measures of the HI shape properties. We quantify asymmetries using a flux ratio parameter.
- ID:
- ivo://CDS.VizieR/J/A+A/609/A17
- Title:
- AMIGA XIII. HI properties
- Short Name:
- J/A+A/609/A17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the largest catalogue of HI single dish observations of isolated galaxies to date, as part of the multi-wavelength compilation being performed by the AMIGA project (Analysis of the interstellar Medium in Isolated GAlaxies). Despite numerous studies of the HI content of galaxies, no revision has been made for the most isolated L* galaxies since Haynes & Giovanelli (1984AJ.....89..758H). The AMIGA sample has been demonstrated to be almost "nurture free", therefore, by creating scaling relations for the HI content of these galaxies we will define a metric of HI normalcy in the absence of interactions. The catalogue comprises of our own HI observations with Arecibo, Effelsberg, Nancay and GBT, and spectra collected from the literature. In total we have measurements or constraints on the HI masses of 844 galaxies from the Catalogue of Isolated Galaxies (CIG). The multi-wavelength AMIGA dataset includes a revision of the B-band luminosities, optical diameters, morphologies, and isolation. Due to the large size of the catalogue, these revisions permit cuts to be made to ensure isolation and a high level of completeness, which was not previously possible. With this refined dataset we fit HI scaling relations based on luminosity, optical diameter and morphology. Our regression model incorporates all the data, including upper limits, and accounts for uncertainties in both variables, as well as distance uncertainties. The HI scaling relations of the AMIGA sample define an up-to-date metric of the HI content of almost "nurture free" galaxies. These relations allow the expected HI mass, in the absence of interactions, of an individual galaxy to be predicted to within 0.25dex (for typical measurement uncertainties). These relations are thus suitable for use as statistical measures of the impact of interactions on the neutral gas content of galaxies.
