J/MNRAS/490/566 HI-bearing ultra-diffuse ALFALFA galaxies (Janowiecki+, 2019) ================================================================================ The environment of H I-bearing ultra-diffuse galaxies in the ALFALFA survey. Janowiecki S., Jones M.G., Leisman L., Webb A. =2019MNRAS.490..566J (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Galaxies, photometry ; H I data ; Positional data ; Optical Keywords: galaxies: evolution - galaxies: ISM - galaxies: structure Abstract: We explore the environment of 252 HI-bearing ultra-diffuse galaxies (HUDs) from the 100 per cent ALFALFA survey catalogue in an attempt to constrain their formation mechanism. We select sources from ALFALFA with surface brightnesses, magnitudes, and radii consistent with other samples of ultra-diffuse galaxies (UDGs) without restrictions on their isolation or environment, more than doubling the previously reported ALFALFA sample. We quantify the galactic environment of HUDs using several metrics, including n^th^ nearest neighbour, tidal influence, membership in a group/cluster, and distance from nearest group/cluster or filament. We find that HUDs inhabit the same environments as other samples of HI-selected galaxies and that they show no environmental preference in any metric. We suggest that these results are consistent with a picture of the extreme properties of HUDs being driven by internal mechanisms and that they are largely unperturbed by environmental impacts. While environmental effects may be necessary to convert HUDs into gas-poor cluster UDGs, these effects are not required for diffuse galaxies to exist in the first place. Description: In this work, we have expanded on the efforts of Leisman et al. (2017ApJ...842..133L, Cat. J/ApJ/842/133) and selecting two samples of HUDs (restrictive and broad) from SDSS and ALFALFA (100 per cent) (Haynes et al. 2018ApJ...861...49H, Cat. J/ApJ/861/49) survey observations, now with no environmental restriction included in the selection process. We also selected matched comparison samples for each HUDs sample based on their HI masses and distances, to test for differences in the environmental preferences of HUDs. We choose to follow Leisman et al. (2017ApJ...842..133L, Cat. J/ApJ/842/133) in defining a restrictively selected sample (HUDs-R) of 71 HI-bearing ultra-diffuse sources with half-light radii r_g,eff_>1.5kpc, {mu}_g,0_>24mag/arcsec^2^, and M_g_>-16.8mag, and a more broadly selected sample (HUDs-B) of 183 sources with r_r,eff_>1.5kpc, <{mu}(r, r_eff_)>>24mag/arcsec^2^, and M_r_>-17.6 (corresponding to the surface brightness and radius limits from van Dokkum et al. 2015ApJ...798L..45V and van der Burg, Muzzin & Hoekstra 2016A&A...590A..20V, respectively, with absolute magnitude limits as defined by Leisman et al. 2017ApJ...842..133L, Cat. J/ApJ/842/133). Table A1 gives the observed quantities and optical properties of our sample. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file tablea1.dat 70 254 Observations and derived optical properties of HUDs-R and HUDs-B samples -------------------------------------------------------------------------------- See also: J/ApJ/842/133 : HI-bearing ultra-diffuse ALFALFA galaxies (Leisman+, 2017) J/ApJ/861/49 : ALFALFA extragalactic HI source catalog (Haynes+, 2018) II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009) Byte-by-byte Description of file: tablea1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 A6 --- Sample HUDs sample (HUDs-R (71 galaxies) or HUDs-B (183 galaxies)) 8- 13 I6 --- Name Galaxy AGC identifier (NNNNNN) 15- 16 I2 h RAh Right ascension (J2000) 18- 19 I2 min RAm Right ascension (J2000) 21- 24 F4.1 s RAs Right ascension (J2000) 26 A1 --- DE- Declination sign (J2000) 27- 28 I2 deg DEd Declination (J2000) 30- 31 I2 arcmin DEm Declination (J2000) 33- 34 I2 arcsec DEs Declination (J2000) 36- 40 F5.1 Mpc D Distance 42- 45 F4.2 Msun logMHI Logarithm of the HI mass of the galaxy 47- 51 F5.1 mag gMAG Absolute magnitude in the SDSS g-band 53- 56 F4.1 mag/arcsec2 mug Surface brightness in the SDSS g-band 58- 60 F3.1 mag/arcsec2 e_mug Error on mug 62- 65 F4.1 arcsec reg Half-light radius in the SDSS g-band 67- 70 F4.1 arcsec e_reg Error on reg -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Ana Fiallos [CDS] 25-Jan-2023