J/MNRAS/473/1879 VVDS14h redshift catalog (Rhee+, 2018)
Neutral hydrogen (H I) gas content of galaxies at z ~= 0.32.
Rhee J., Lah P., Briggs F.H., Chengalur J.N., Colless M., Willner S.P.,
Ashby M.L.N., Le Fevre O.
<Mon. Not. R. Astron. Soc., 473, 1879-1894 (2018)>
=2018MNRAS.473.1879R 2018MNRAS.473.1879R (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Redshifts
Keywords: galaxies: evolution - galaxies: ISM - radio lines: galaxies
Abstract:
We use observations made with the Giant Metrewave Radio Telescope
(GMRT) to probe the neutral hydrogen (HI) gas content of field
galaxies in the VIMOS VLT Deep Survey (VVDS) 14h field at z~=0.32.
Because the HI emission from individual galaxies is too faint to
detect at this redshift, we use an HI spectral stacking technique
using the known optical positions and redshifts of the 165 galaxies in
our sample to co-add their HI spectra and thus obtain the average HI
mass of the galaxies. Stacked HI measurements of 165 galaxies show
that ≳95 per cent of the neutral gas is found in blue, star-forming
galaxies. Among these galaxies, those having lower stellar mass are
more gas rich than more massive ones. We apply a volume correction to
our HI measurement to evaluate the HI gas density at z~=0.32 as
{OMETA}HI=(0.50±0.18)x10-3 in units of the cosmic critical
density. This value is in good agreement with previous results at
z<0.4, suggesting no evolution in the neutral hydrogen gas density
over the last ∼4Gyr. However the z~=0.32 gas density is lower than
that at z∼5 by at least a factor of two.
Description:
The effective field of view for our optical spectroscopic observations
corresponds to a circular field of one degree diameter, smaller than
the total area of 2.2deg2 surveyed for the VVDS 14h field in the
original VVDS-Wide. This field has good optical imaging coverage in
both R and I bands along with Sloan Digital Sky Survey (SDSS) imaging.
Hectospec and AAOmega are ideal spectrographs for efficiently
obtaining a large number of galaxy redshifts because they have large
fields of view and many fibres to simultaneously obtain spectra. The
Hectospec instrument has 300 fibres and a field of view one degree in
diameter. Wavelength coverage is 3700-9200Å at 1.2Å/pix and
R∼1000-2000. MMT observations of six fibre configurations were carried
out in queue observing mode over five nights between 2011 February and
April with a 1.5hr exposure time (divided into three 0.5 hr exposures
for cosmic ray removal) for each fibre configuration. 1526 of 2240
target galaxies, corresponding to ∼68 per cent of our sample,
were successfully observed.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 113 1640 Catalogue containing redshift data for all
sources taken by AAOmega and Hectospec
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- n_objID [*] * denotes an object taken from both
instruments
2- 19 I18 --- objID SDSS objID
23- 34 F12.8 deg RAdeg Right ascension (J2000)
38- 47 F10.8 deg DEdeg Declination (J2000)
51- 52 I2 h RAh Right ascension (J2000)
54- 55 I2 min RAm Right ascension (J2000)
57- 61 F5.2 s RAs Right ascension (J2000)
64 A1 --- DE- Declination sign (J2000)
65 I1 deg DEd Declination (J2000)
67- 68 I2 arcmin DEm Declination (J2000)
70- 73 F4.1 arcsec DEs Declination (J2000)
76- 84 F9.6 --- z Redshift
88- 95 F8.6 --- e_z rms uncertainty on z
99 I1 --- f_z [3/5]? Reshift flag (1)
105-113 A9 --- Inst Instrument (AAOmega or Hectospec)
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Note (1): Reshift flag as follows:
3 = Probable redshift showing a couple of spectral lines with low SNR
4 = Reliable redshift with a mixture of strong and weak spectral lines
5 = 100 per cent convincing redshift with high SNR multiple emission or
absorption lines
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Nov-2020