Metal Abundances and Kinematics of Quasar Absorbers. II. Absorption Systems toward Q0347−3819 and APM BR J0307−4945

Detailed Monte Carlo Inversion analysis of the spectral lines from threeLyman 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 ofQ0347-3819 (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 indifferent environments. A functional dependence of the line-of-sight velocitydispersion sigma_v on the absorber size L is confirmed: the majority of theanalyzed systems follow the scaling relation sigma_v ~ (N_H L)^{0.3} (with N_Hbeing the total gas column density). This means that most absorbers may berelated to virialized systems like galaxies or their halos. Previously notedenhancement 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 linearsizes. 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 systemsexhibit characteristics which are very similar to that observed inhigh-velocity clouds in the Milky Way and may be considered as high-redshiftcounterparts of Galactic HVCs.Comment: 21 pages, 4 tables, 18 figures, accepted by the Ap