Heinmüller, J. ; Petitjean, P. ; Ledoux, C. ; Caucci, S. ; Srianand, R. (2006) Kinematics and star formation activity in the zabs = 2.03954 damped Lyman-α system towards PKS 0458-020 Astronomy and Astrophysics, 449 (1). pp. 33-39. ISSN 0004-6361
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Official URL: http://www.aanda.org/articles/aa/abs/2006/13/aa391...
Related URL: http://dx.doi.org/10.1051/0004-6361:20053910
Abstract
We present UVES observations of the log N(H I) = 21.7 damped Lyman-α system at Zabs = 2.03954 towards the quasar PKS 0458-020. H I Lyman-α emission is detected in the center of the damped Lyman- absorption trough. Metallicities are derived for Mg II, Si II, P II, Cr II, Mn II, Fe II and Zn II and are found to be -1.21 ± 0.12, -1.28 ± 0.20, -1.54 ± 0.11, -1.66 ± 0.19, -2.05 ± 0.11, -1.87 ± 0.11, -1.22 ± 0.10, respectively, relative to solar. The depletion factor is therefore of the order of [Zn/Fe] = 0.65. We observe metal absorption lines to be blueshifted compared to the Lyman-α emission up to a maximum of ∼100 and 200 km s-1 for low and high-ionization species respectively. This can be interpreted either as the consequence of rotation in a large (∼7 kpc) disk or as the imprint of a galactic wind. The star formation rate (SFR) derived from the Lyman-α emission, 1.6 yr MΘ -1, is compared with that estimated from the observed C II absorption. No molecular hydrogen is detected in our data, yielding a molecular fraction log ƒ < -6.52. This absence of H2 can be explained as the consequence of a high ambient UV flux which is one order of magnitude larger than the radiation field in the ISM of our Galaxy and originates in the observed emitting region.
Item Type: | Article |
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Source: | Copyright of this article belongs to EDP Sciences. |
Keywords: | Cosmology; Observations; Galaxies; Abundances; Galaxies; Quasars; Absorption Lines; Galaxies; Quasars; Individual; PKS0458-020; Galaxies; Kinematics and Dynamics |
ID Code: | 55235 |
Deposited On: | 18 Aug 2011 08:06 |
Last Modified: | 18 May 2016 07:35 |
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