Are the kinematics of DLAs in agreement with their arising in the gas disks of galaxies?

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Are the kinematics of DLAs in agreement with their arising in the gas disks of galaxies?

Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/58028

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Title: Are the kinematics of DLAs in agreement with their arising in the gas disks of galaxies?
Author(s): Zwaan, Martin; Walter, Fabian; Ryan-Weber, Emma; Brinks, Elias; De Blok, W. J. G.; Kennicutt, Robert C.
Abstract: We demonstrate in this paper that the velocity widths of the neutral gas in damped Lyα (DLA) systems are inconsistent with these systems originating in gas disks of galaxies, similar to those seen in the local universe. We examine the gas kinematics of local galaxies using the high-quality H I 21 cm data from the H I Nearby Galaxies Survey and make a comparison with the velocity profiles measured in the low-ionization metal lines observed in DLAs at high redshifts. The median velocity width of z = 0 H I gas above the DLA column density limit of N H I = 2 × 1020 cm–2 is approximately 30 km s–1, whereas the typical value in DLAs is a factor of 2 higher. We argue that the gas kinematics at higher redshifts are increasingly influenced by gas that is not participating in ordered rotation in cold disks, but is more likely associated with tidal gas related to galaxy interactions or processes such as superwinds and outflows. An analysis of the H I in the local interacting starburst galaxy M 82 shows that the velocity widths in this galaxy are indeed similar to what is seen in DLAs.
Publication type: Journal article
Source: Astronomical Journal, Vol. 136, no. 6 (Nov 2008), pp. 2886-2896
Publication year: 2008
FOR Code(s): 0201 Astronomical and Space Sciences
Keyword(s): Absorption lines; Galaxy evolution; ISM; ISM kinematics and dynamics; Quasars; Radio lines
Publisher: University of Chicago Press
ISSN: 0004-6256
Publisher URL: http://dx.doi.org/10.1088/0004-6256/136/6/2886
Copyright: Copyright © 2008. The American Astronomical Society. All rights reserved. Publisher does not officially support archiving of either the postprint (final, revised accepted draft) or published version of full text in institutional repositories.
Peer reviewed