Chemical enrichment and host galaxies of extremely-strong intervening DLAs towards quasars

Abstract

We present the results from VLT/X-shooter spectroscopic observations of 11 extremely strong intervening damped Lyman-alpha absorbers (ESDLAs) initially selected as high N(Hi) (i.e.>=5x10^21 cm-2) candidates from the Sloan Digital Sky Survey (SDSS). We confirm the high Hi column densities which we measure to be in the range log N(Hi) = 21.6-22.4. Molecular hydrogen is detected with high column densities (N(H_2)>=10^18 cm-2) in five out of eleven systems, three of which are reported here for the first time. We compare the chemical properties of this sample of ESDLAs, supplemented with literature measurements, to that of DLAs located at the redshift of long-duration gamma-ray bursts (GRB-DLAs). We confirm that the two populations are almost indistinguishable in terms of chemical enrichment, H_2 column density and gas kinematics. All this suggests that ESDLAs and GRB-DLAs probe similar galactic environments. We search for the galaxy counterparts of ESDLAs and find associated emission lines in three out of eleven systems, two of which are reported here for the first time (towards the quasars SDSS J002503.03+114547.80 and SDSS J114347.21+142021.60, respectively). The measured separations between the quasar sightlines and the emission associated with the ESDLA galaxy are all very small (rho < 3 kpc). While the small impact parameters are similar to what is observed for GRB-DLAs, the associated star-formation rates are on average lower than seen for GRB host galaxies. This is explained by long-duration GRBs being associated with the death of massive stars, hence pinpointing regions of active star formation in the GRB host galaxies. Our observations support the suggestion from the literature that ESDLAs could act as blind analogues of GRB-DLAs, probing high column density neutral gas in the heart of high-redshift galaxies, without any prior on the instantaneous star-formation rate.

13 page paper with 8 additional appendix pages, 10 main figures with 23 figures in appendix

References in corpus (17)

• The Supernova -- Gamma-Ray Burst Connection
• Astrophysics Source Code Library
• Long gamma-ray bursts and core-collapse supernovae have different environments
• The Role of Pressure in GMC Formation II: The H_2 - Pressure Relation
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• Velocity-Metallicity Correlation for high-z DLA Galaxies: Evidence for a Mass-Metallicity Relation?
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• Damped Lyman-alpha absorbers as a probe of stellar feedback
• A connection between extremely strong Damped Lyman-alpha Systems and Lyman-alpha Emitting Galaxies at small impact parameters
• Dust-depletion sequences in damped Lyman-α absorbers: a unified picture from low-metallicity systems to the Galaxy
• Mining for Dust in Type 1 Quasars
• CO-dark molecular gas at high redshift: very large H${}_2$ content and high pressure in a low metallicity damped Lyman-alpha system
• Molecular hydrogen absorption systems in Sloan Digital Sky Survey
• On the mass-metallicity relation, velocity dispersion and gravitational well depth of GRB host galaxies
• Mass and metallicity scaling relations of high redshift star-forming galaxies selected by GRBs
• The effect of dust bias on the census of neutral gas and metals in the high-redshift Universe due to SDSS-II quasar colour selection
• The ESO UVES Advanced Data Products Quasar Sample-V. Identifying the Galaxy Counterpart to the sub-Damped Ly-alpha System towards Q2239-2949

Cited by in corpus (8)

• High-redshift Damped Ly-alpha Absorbing Galaxy Model Reproducing the N(HI)-Z Distribution
• The nature of H{\sc i}-absorption-selected galaxies at $z\approx 4$
• HD molecules at high redshift: cosmic-ray ionization rate in the diffuse interstellar medium
• Nature of the DLA towards Q0528-250: High pressure and strong UV field revealed by excitation of CI, H2 and SiII
• Modeling the Statistics of the Cold Neutral Medium in Absorption-selected High-redshift Galaxies
• CII*/CII ratio in high-redshift DLAs: ISM phase separation drives the observed bimodality of [CII] cooling rates
• Physical conditions in two high-redshift H${}_2$-bearing GRB-DLAs, 120815A and 121024A
• GRB host galaxies with strong H${}_2$ absorption: CO-dark molecular gas at the peak of cosmic star formation