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.
<Mon. Not. R. Astron. Soc., 490, 566-577 (2019)>
=2019MNRAS.490..566J 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 nth 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 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 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 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
rg,eff>1.5kpc, µg,0>24mag/arcsec2, and Mg>-16.8mag, and a
more broadly selected sample (HUDs-B) of 183 sources with
rr,eff>1.5kpc, <µ(r, reff)≫24mag/arcsec2, and Mr>-17.6
(corresponding to the surface brightness and radius limits from van
Dokkum et al. 2015ApJ...798L..45V 2015ApJ...798L..45V and van der Burg, Muzzin & Hoekstra
2016A&A...590A..20V 2016A&A...590A..20V, respectively, with absolute magnitude limits as
defined by Leisman et al. 2017ApJ...842..133L 2017ApJ...842..133L, Cat. J/ApJ/842/133).
Table A1 gives the observed quantities and optical properties of our
sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 70 254 Observations and derived optical properties of
HUDs-R and HUDs-B samples
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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
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Bytes Format Units Label Explanations
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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
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 25-Jan-2023