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 samplewith measurements having similar optical depth sensitivity (∫ τdv =0.3 kms-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 0.24-0.08+0.12 at b ≤ 15 kpc and 0.06-0.04+0.09 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.

Dutta, R., Srianand, R., Gupta, N., Momjian, E., Noterdaeme, P., Petitjean, P., et al. (2017). 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, 465(1), 588-618 [10.1093/mnras/stw2689].

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

Dutta R.
;
2017

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 samplewith measurements having similar optical depth sensitivity (∫ τdv =0.3 kms-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 0.24-0.08+0.12 at b ≤ 15 kpc and 0.06-0.04+0.09 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.
Articolo in rivista - Articolo scientifico
Galaxies: ISM; Quasars: absorption line;
English
19-ott-2016
2017
465
1
588
618
open
Dutta, R., Srianand, R., Gupta, N., Momjian, E., Noterdaeme, P., Petitjean, P., et al. (2017). 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, 465(1), 588-618 [10.1093/mnras/stw2689].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/316775
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