- ID:
- ivo://CDS.VizieR/J/ApJ/866/33
- Title:
- The COS CGM compendium. I. Initial results
- Short Name:
- J/ApJ/866/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a neutral hydrogen-selected absorption-line survey of gas with HI column densities 15<logN_HI_<19 at z<~1 using the Cosmic Origins Spectrograph on the Hubble Space Telescope. Our main aim is to determine the metallicity distribution of these absorbers. Our sample consists of 224 absorbers selected on the basis of their HI absorption strength. Here we discuss the properties of our survey and the immediate empirical results. We find singly and doubly ionized metal species, and HI typically have similar velocity profiles, implying they probe gas in the same or similar environments. The ionic ratios (e.g., N_CII_/N_CIII_, N_OI_/N_CII_) indicate that the gas in these absorbers is largely ionized, and the ionization conditions are quite comparable across the sampled N_HI_ range. The Doppler parameters of the HI imply T<~5x10^4^K on average, consistent with the gas being photoionized. The MgII column densities span >2 orders of magnitude at any given N_HI_, indicating a wide range of metallicities (from solar to <1/100 solar). In the range of 16.2<~logN_HI_<~17, there is a gap in the N_MgII_ distribution corresponding to gas with ~10% solar metallicity, consistent with the gap seen in the previously identified bimodal metallicity distribution in this column density regime. Less than 3% of the absorbers in our sample show no detectable metal absorption, implying that truly pristine gas at z<~1 is uncommon. We find <[FeII/MgII]>=-0.4+/-0.3, and since {alpha}-enhancement can affect this ratio, dust depletion is extremely mild.
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262. The EZOA survey
- ID:
- ivo://CDS.VizieR/J/MNRAS/489/2907
- Title:
- The EZOA survey
- Short Name:
- J/MNRAS/489/2907
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of galaxies in the northern Zone of Avoidance (ZoA), extracted from the shallow version of the blind HI survey with the Effelsberg 100m radio telescope, EBHIS, that has a sensitivity of 23mJy/beam at 10.24km/s velocity resolution. The catalogue comprises 170 detections in the region Dec>=-5{deg} and |b|<6{deg}. About a third of the detections (N=67) have not been previously recorded in HI. While 29 detections have no discernible counterpart at any wavelength other than HI, 48 detections (28%) have a counterpart visible on optical or NIR images but are not recorded as such in the literature. New HI detections were found as close as 7.5Mpc (EZOA J2120+45), and at the edge of the Local Volume, at 10.1Mpc, we have found two previously unknown dwarf galaxies (EZOA J0506+31 and EZOA J0301+56). Existing large-scale structures crossing the northern ZoA have been established more firmly by the new detections, with the possibility of new filaments. We conclude that the high rate of 39% new HI\detections in the northern ZoA, which has been extensively surveyed with targeted observations in the past, proves the power of blind HI surveys. The full EBHIS survey, which will cover the full northern sky with a sensitivity comparable to the HIPASS survey of the southern sky, is expected to add many new detections and uncover new structures in the northern ZoA.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A108
- Title:
- The Fourcade-Figueroa galaxy
- Short Name:
- J/A+A/652/A108
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Studies of the stellar and the HI gas kinematics in dwarf and Low Surface Brightness (LSB) galaxies are essential for deriving constraints on their dark matter distribution. Moreover, a key component to unveil in the evolution of LSBs is why some of them can be classified as superthin. We aim to investigate the nature of the proto-typical superthin galaxy Fourcade-Figueroa (FF), to understand the role played by the dark matter halo in forming its superthin shape and to investigate the mechanism that explains the observed disruption in the approaching side of the galaxy. Combining new HI 21-cm observations obtained with the Giant Metrewave Radio Telescope with archival data from the Australia Telescope Compact Array we were able to obtain sensitive HI observations of the FF galaxy. These data were modeled with a 3D tilted ring model in order to derive the rotation curve and surface brightness density of the neutral hydrogen. We subsequently used this model, combined with a stellar profile from the literature, to derive the radial distribution of the dark matter in the FF galaxy. Additionally, we used a more direct measurement of the vertical HI gas distribution as a function of the galactocentric radius to determine the flaring of the gas disk. For the FF galaxy the Navarro-Frenk-White dark matter distribution provides the best fit to the observed rotation curve. However, the differences with a pseudo-isothermal halo are small. Both models indicate that the core of the dark matter halo is compact. Even though the FF galaxy classifies as superthin, the gas thickness about the galactic centre exhibits a steep flaring of the gas which is in agreement with the edge of the stellar disk. Besides, FF is clearly disrupted towards its north-west-side, clearly observed at both, optical and HI wavelengths. As suggested previously in the literature, the compact dark matter halo might be the main responsible for the superthin structure of the stellar disk in FF. This idea is strengthened through the detection of the mentioned disruption; the fact that the galaxy is disturbed also seems to support the idea that it is not isolation that cause its superthin structure.
- ID:
- ivo://CDS.VizieR/J/ApJ/758/44
- Title:
- The GALFA-HI compact cloud catalog
- Short Name:
- J/ApJ/758/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 1964 isolated, compact neutral hydrogen clouds from the Galactic Arecibo L-Band Feed Array Survey Data Release One. The clouds were identified by a custom machine-vision algorithm utilizing the difference of Gaussian kernels to search for clouds smaller than 20'. The clouds have velocities typically between |V_LSR_|=20 and 400km/s, line widths of 2.5-35km/s, and column densities ranging from 1 to 35x10^18^/cm2. The distances to the clouds in this catalog may cover several orders of magnitude, so the masses may range from less than a solar mass for clouds within the Galactic disk, to greater than 10^4^M_{sun}_for high-velocity clouds (HVCs) at the tip of the Magellanic Stream. To search for trends, we separate the catalog into five populations based on position, velocity, and line width: HVCs; galaxy candidates; cold low-velocity clouds (LVCs); warm, low positive-velocity clouds in the third Galactic quadrant; and the remaining warm LVCs. The observed HVCs are found to be associated with previously identified HVC complexes. We do not observe a large population of isolated clouds at high velocities as some models predict. We see evidence for distinct histories at low velocities in detecting populations of clouds corotating with the Galactic disk and a set of clouds that is not corotating.
- ID:
- ivo://CDS.VizieR/J/ApJS/234/2
- Title:
- The GALFA-HI survey data release 2
- Short Name:
- J/ApJS/234/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Galactic Arecibo L-Band Feed Array HI (GALFA-HI) survey data release 2 (DR2). The survey covers the 21cm hyperfine transition of Galactic HI from -650 to 650km/s, with 0.184km/s channel spacing, 4' angular resolution, and 150mK rms noise per 1km/s velocity channel. DR2 covers the entirety of the sky available from the William E. Gordon 305m antenna at Arecibo, from decl. -1{deg}17' to decl. +37{deg}57' across all R.A.: 4 steradians or 32% of the sky. DR2 differs in a number of ways from data release 1, which was released in 2011. DR2 is built from a largely separate set of observations from DR1, which were taken in a much more consistent mode. This consistency, coupled with more careful attention to systematics and more advanced data reduction algorithms, leads to a much higher-quality DR2 data product. We present three data sets for public use: HI data cubes, far- sidelobe stray-radiation-corrected column density maps, and results of the Rolling Hough Transform linear feature detection algorithm.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/40
- Title:
- The HIPASS Catalog (HICAT) + WISE galaxies
- Short Name:
- J/ApJ/864/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the relationships between HI mass, stellar mass, and star formation rate using the HI Parkes All-Sky Survey Catalog (HICAT) and the Wide-field Infrared Survey Explorer (WISE). Of the 3513 HICAT sources, we find 3.4{mu}m counterparts for 2896 sources (80%), and provide new WISE-matched aperture photometry for these galaxies. For our principal sample of spiral galaxies with W1<=10mag and z<=0.01, we identify HI detections for 93% of the sample. We measure lower HI-stellar mass relationships for 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 of 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 at 10^-9.57^yr^-1^+/-0.4dex for 2.5 orders of magnitude in stellar mass, despite the higher stellar mass spiral showing evidence of quenched star formation.
267. The HIZOA-S survey
- ID:
- ivo://CDS.VizieR/J/AJ/151/52
- Title:
- The HIZOA-S survey
- Short Name:
- J/AJ/151/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A blind HI survey of the extragalactic sky behind the southern Milky Way has been conducted with the multibeam receiver on the 64m Parkes radio telescope. The survey covers the Galactic longitude range 212{deg}<l<36{deg} and Galactic latitudes |b|<5{deg} to an rms sensitivity of 6mJy per beam per 27km/s channel and yields 883 galaxies to a recessional velocity of 12000km/s. The survey covers the sky within the HI Parkes All-Sky Survey (HIPASS) area to greater sensitivity, finding lower HI mass galaxies at all distances, and probing more completely the large-scale structures at and beyond the distance of the Great Attractor. Fifty-one percent of the HI detections have an optical/near-infrared (NIR) counterpart in the literature. A further 27% have new counterparts found in existing, or newly obtained, optical/NIR images. The counterpart rate drops in regions of high foreground stellar crowding and extinction, and for low HI mass objects. Only 8% of all counterparts have a previous optical redshift measurement. The HI sources are found independently of Galactic extinction, although the detection rate drops in regions of high Galactic continuum. The survey is incomplete below a flux integral of approximately 3.1Jy/km/s and mean flux density of approximately 21mJy, with 75% and 81% of galaxies being above these limits, respectively. Taking into account dependence on both flux and velocity width, and constructing a scaled dependence on the flux integral limit with velocity width (w^0.74^), completeness limits of 2.8Jy/km/s and 17mJy are determined, with 92% of sources above these limits. A notable new galaxy is HIZOA J1353-58, a possible companion to the Circinus galaxy. Merging this catalog with the similarly conducted northern extension, large-scale structures are delineated, including those within the Puppis and Great Attractor regions and the Local Void. Several newly identified structures are revealed here for the first time. Three new galaxy concentrations (NW1, NW2, and NW3) are key in confirming the diagonal crossing of the Great Attractor Wall between the Norma Cluster and the CIZA J1324.7-5736 cluster. Further contributors to the general mass overdensity in that area are two new clusters (CW1 and CW2) in the nearer Centaurus Wall, one of which forms part of the striking 180{deg} (100h^-1^Mpc) long filament that dominates the southern sky at velocities of ~3000 km/s, and the suggestion of a further wall at the Great Attractor distance at slightly higher longitudes.
- ID:
- ivo://CDS.VizieR/J/A+A/580/A112
- Title:
- THOR. The HI, OH, Recombination Line Survey
- Short Name:
- J/A+A/580/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To study the atomic, molecular and ionized emission of Giant Molecular Clouds (GMCs), we have initiated a Large Program with the VLA: 'THOR - The HI, OH, Recombination Line survey of the Milky Way'. We map the 21cm HI line, 4 OH lines, 19 H{alpha} recombination lines and the continuum from 1 to 2GHz of a significant fraction of the Milky Way (l=15-67{deg}, |b|<1{deg}) at ~20" resolution. In this paper, we focus on the HI emission from the W43 star-formation complex. Classically, the HI 21cm line is treated as optically thin with column densities calculated under this assumption. This might give reasonable results for regions of low-mass star-formation, however, it is not sufficient to describe GMCs. We analyzed strong continuum sources to measure the optical depth, and thus correct the HI 21cm emission for optical depth effects and weak diffuse continuum emission. Hence, we are able to measure the HI mass of W43 more accurately and our analysis reveals a lower limit of M=6.6x10^6^M_{sun}_, which is a factor of 2.4 larger than the mass estimated with the assumption of optically thin emission. The HI column densities are as high as N(HI)~150M_{sun}_/pc^2^~1.9x10^22cm^-2^, which is an order of magnitude higher than for low mass star formation regions. This result challenges theoretical models that predict a threshold for the HI column density of ~10M_{sun}_/pc^2^, at which the formation of molecular hydrogen should set in. By assuming an elliptical layered structure for W43, we estimate the particle density profiles. While at the cloud edge atomic and molecular hydrogen are well mixed, the center of the cloud is strongly dominated by molecular hydrogen. We do not identify a sharp transition between hydrogen in atomic and molecular form. Our results are an important characterization of the atomic to molecular hydrogen transition in an extreme environment and challenges current theoretical models.
- ID:
- ivo://CDS.VizieR/J/AJ/157/194
- Title:
- Total ALFALFA H I fluxes for extended sources
- Short Name:
- J/AJ/157/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A procedure is presented to improve on measurement of total H I fluxes for extended sources in the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey of neutral hydrogen sources in the nearby universe. A number of tests of the procedure are detailed, and we verify that we recover all of the flux measured with much larger telescope beams. Total fluxes are reported for all sources (1) exceeding 10 Jy km/s in the {alpha}.100 catalog (Haynes et al. 2018ApJ...861...49H), or (2) with Uppsala General Catalog (Cat. VII/26) diameters 3.0 arcmin or more, or (3) ALFALFA pipeline isophotal ellipse area more than 3.0 times the Arecibo beam. Total fluxes are also provided for a number of confused pairs and small groups including one or more of those high-flux sources. These data should be of use in baryonic Tully-Fisher studies and other applications where the measurement of the total reservoir of neutral atomic gas is important.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A113
- Title:
- Towards Cosmicflows-4 HI data catalog
- Short Name:
- J/A+A/646/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this study, we present an update of a compilation of line width measurements of neutral atomic hydrogen (HI) galaxy spectra at 21 cm wavelength. Our All Digital HI (ADHI) catalog consists of the previous release augmented with our new HI observations and an analysis of archival data. This study provides the required HI information to measure the distances of spiral galaxies through the application of the Tully-Fisher (TF) relation. We conducted observations at the Green Bank telescope (GBT) and reprocessed spectra obtained at the Nancay radiotelescope by the Nancay Interstellar Baryons Legacy Extragalactic Survey (NIBLES) and Kinematics of the Local Universe (KLUN) collaborations and we analyzed the recently published full completion Arecibo Legacy Fast ALFA (ALFALFA) 100% survey in order to identify galaxies with good quality HI line width measurements. This paper adds new HI data adequate for TF use for 385 galaxies observed at GBT, 889 galaxies from archival Nancay spectra, and 1515 rescaled Arecibo ALFALFA spectra. In total, this release adds 1274 new good quality measurements to the ADHI catalog. Today, the ADHI database contains 18,874 galaxies, for which 15,433 have good quality data for TF use. The final goal is to compute accurate distances to spiral galaxies, which will be included in the next generation of peculiar velocities catalog: Cosmicflows-4. This paper adds new HI data adequate for TF use for 385 galaxies observed at GBT, 889 galaxies from archival Nancay spectra, and 1515 rescaled Arecibo ALFALFA spectra. In total, this release adds 1274 new good quality measurements to the ADHI catalog. Today, the ADHI database contains 18874 galaxies, for which 15433 have good quality data for TF use. The final goal is to compute accurate distances to spiral galaxies, which will be included in the next generation of peculiar velocities catalog: Cosmicflows-4.
