H I 21-cm absorption survey of quasar-galaxy pairs: distribution of cold gas around z < 0.4 galaxies - Archive ouverte HAL Access content directly
Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2017

H I 21-cm absorption survey of quasar-galaxy pairs: distribution of cold gas around z < 0.4 galaxies

, , , , (1) , (1) , (2)
1
2
R. Dutta
  • Function : Author
R. Srianand
N. Gupta
E. Momjian
P. Noterdaeme

Abstract

We present the results from our survey of H I 21-cm absorption, using Giant Metrewave Radio Telescope, Very Large Array and Westerbork Radio Synthesis Telescope, in a sample of 55 z < 0.4 galaxies towards radio sources with impact parameters (b) in the range ∼0-35 kpc. In our primary sample (defined for statistical analyses) of 40 quasar-galaxy pairs, probed by 45 sightlines, we have found seven H I 21-cm absorption detections, two of which are reported here for the first time. Combining our primary sample with measurements having similar optical depth sensitivity (∫τdv ≤ 0.3 km s-1) from the literature, we find a weak anti-correlation (rank correlation coefficient = -0.20 at 2.42σ level) between ∫τdv and b, consistent with previous literature results. The covering factor of H I 21-cm absorbers (C21) is estimated to be 0.24^{+0.12}_{-0.08} at b ≤ 15 kpc and 0.06^{+0.09}_{-0.04} at b = 15-35 kpc. ∫τdv and C21 show similar declining trend with radial distance along the galaxy's major axis and distances scaled with the effective H I radius. There is also tentative indication that most of the H I 21-cm absorbers could be co-planar with the extended H I discs. No significant dependence of ∫τdv and C21 on galaxy luminosity, stellar mass, colour and star formation rate is found, though the H I 21-cm absorbing gas cross-section may be larger for the luminous galaxies. The higher detection rate (by a factor of ∼4) of H I 21-cm absorption in z < 1 damped Lyman-α systems compared to the quasar-galaxy pairs indicates towards small covering factor and patchy distribution of cold gas clouds around low-z galaxies.
Fichier principal
Vignette du fichier
stw2689.pdf (3.69 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03666210 , version 1 (12-05-2022)

Identifiers

Cite

R. Dutta, R. Srianand, N. Gupta, E. Momjian, P. Noterdaeme, et al.. H I 21-cm absorption survey of quasar-galaxy pairs: distribution of cold gas around z < 0.4 galaxies. Monthly Notices of the Royal Astronomical Society, 2017, 465, pp.588-618. ⟨10.1093/mnras/stw2689⟩. ⟨insu-03666210⟩
9 View
8 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More