Kanekar, N. ; Lane, W. M. ; Momjian, E. ; Briggs, F. H. ; Chengalur, J. N. (2009) The covering factor of high-redshift damped Lyman-α systems Monthly Notices of the Royal Astronomical Society: Letters, 394 (1). L61-L65. ISSN 1745-3925
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Official URL: http://doi.org/10.1111/j.1745-3933.2008.00610.x
Related URL: http://dx.doi.org/10.1111/j.1745-3933.2008.00610.x
Abstract
We have used the Very Long Baseline Array to image 18 quasars with foreground damped Lyman-α systems (DLAs) at 327, 610 or 1420 MHz, to measure the covering factor f of each DLA at or near its redshifted H I 21 cm line frequency. Including six systems from the literature, we find that none of 24 DLAs at 0.09 < z < 3.45 has an exceptionally low covering factor, with f∼ 0.45–1 for the 14 DLAs at z > 1.5 and f∼ 0.41–1 for the 10 systems at z < 1, and consistent covering factor distributions in the two subsamples. The observed paucity of detections of H I 21 cm absorption in high-z DLAs thus cannot be explained by low covering factors and is instead likely to arise due to a larger fraction of warm H I in these absorbers.
Item Type: | Article |
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Source: | Copyright of this article belongs to Oxford University Press. |
Keywords: | Galaxies: ISM; Quasars: Individual: Images. |
ID Code: | 118109 |
Deposited On: | 14 May 2021 05:35 |
Last Modified: | 14 May 2021 05:35 |
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