Metal Abundances and Kinematics of Quasar Absorbers. II. Absorption Systems toward Q0347−3819 and APM BR J0307−4945
- 10 January 2003
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 582 (2) , 596-614
- https://doi.org/10.1086/344671
Abstract
Detailed Monte Carlo Inversion analysis of the spectral lines from three Lyman limit systems (LLS) [N(HI) > 10^{17} cm^-2] and nine lower N(HI) systems [2 10^{14} < N(HI) < 2 10^{16} cm^-2] observed in the VLT/UVES spectra of Q0347-3819 (in the range 2.21 <= z <= 3.14) and of APM BR J0307-4945 (at z = 4.21 and 4.81) is presented. Combined with the results from a previous work, the analyzed LLSs show that they are a heterogeneous population originating in different environments. A functional dependence of the line-of-sight velocity dispersion sigma_v on the absorber size L is confirmed: the majority of the analyzed systems follow the scaling relation sigma_v ~ (N_H L)^{0.3} (with N_H being the total gas column density). This means that most absorbers may be related to virialized systems like galaxies or their halos. Previously noted enhancement of the metal content in small size systems is also confirmed: metallicities of Z ~ (1/3-1/2)Z_solar are found in systems with L < 0.4 kpc, whereas we observe much lower metal abundances in systems with larger linear sizes. For the first time in LLSs, a pronounced [alpha-element/iron-peak] enrichment is revealed: the absorber at z = 2.21 shows [O/Fe] = 0.65+/-0.11, [Si/Fe] = 0.51+/-0.11, and [Mg/Fe] = 0.38+/-0.11. Several absorption systems exhibit characteristics which are very similar to that observed in high-velocity clouds in the Milky Way and may be considered as high-redshift counterparts of Galactic HVCs.Comment: 21 pages, 4 tables, 18 figures, accepted by the ApKeywords
All Related Versions
This publication has 41 references indexed in Scilit:
- The Gaseous Extent of Galaxies and the Origin of Lyα Absorption Systems. V. Optical and Near‐Infrared Photometry of Lyα‐absorbing Galaxies atz < 1The Astrophysical Journal, 2001
- The Origin of CivAbsorption Systems at Redshiftsz< 1: Discovery of Extended CivEnvelopes around GalaxiesThe Astrophysical Journal, 2001
- UVES observations of a damped Lyαsystem at $\mathsf{{\vec z}_{abs} = 4.466}$ towards the quasar APM BR J0307-4945Astronomy & Astrophysics, 2001
- A new deuterium abundance measurement from a damped Lyα system at $\vec{z}_{\mathsf{abs}} =\mathsf{3.025}$Astronomy & Astrophysics, 2001
- The Enrichment History of the Intergalactic Medium—Measuring the C [CSC]iv[/CSC]/H [CSC]i[/CSC] Ratio in the L[CLC]y[/CLC]α ForestThe Astronomical Journal, 2000
- Performance of UVES, the echelle spectrograph for the ESO VLT and highlights of the first observations of stars and quasarsPublished by SPIE-Intl Soc Optical Eng ,2000
- The Gaseous Extent of Galaxies and the Origin of Lyα Absorption Systems. III.HubbleSpaceTelescopeImaging of Lyα‐absorbing Galaxies atz< 1The Astrophysical Journal, 1998
- Gravitational collapse of small-scale structure as the origin of the Lyman-alpha forestThe Astrophysical Journal, 1994
- Molecules at early epochs. IV - Confirmation of the detection of H2 toward PKS 0528 - 250The Astrophysical Journal, 1988
- The galactic fountain of high-velocity cloudsThe Astrophysical Journal, 1980