A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to Damped Lyman-alpha Systems - III. Three Additional Detections

TL;DR

This study reports three new detections of galaxy counterparts to damped Lyman-alpha systems using integral field spectroscopy, revealing correlations between metallicity, redshift, and detection probability, and providing insights into galaxy properties at high redshift.

Contribution

It presents three additional detections of galaxy counterparts to DLAs using SINFONI, expanding the sample and enabling comparison of absorption and emission metallicities at high redshift.

Findings

Higher detection probability for systems with higher metallicity.

Increased detection rate at z_abs~1 compared to z_abs~2.

Ability to compare absorption and emission metallicities more than doubles available data.

Abstract

We report three additional SINFONI detections of H-alpha emission line from quasar absorbers, two of which are new identifications. These were targeted among a sample of systems with log N(HI)>19.0 and metallicities measured from high-resolution spectroscopy. The detected galaxies are at impact parameters ranging from 6 to 12 kpc from the quasar's line-of-sight. We derive star formation rates (SFR) of a few solar masses per year for the two absorbers at z_abs~1 and SFR=17 solar masses per year for the DLA at z_abs~2. These three detections are found among a sample of 16 DLAs and sub-DLAs (5 at z_abs~1 and 7 at z_abs~2). For the remaining undetected galaxies, we derive flux limits corresponding to SFR<0.1--11.0 solar masses per year depending on redshift of the absorber and depth of the data. When combined with previous results from our survey for galaxy counterparts to HI-selected absorbers, we find a higher probability of detecting systems with higher metallicity as traced by dust-free [Zn/H] metallicity. We also report a higher detection rate with SINFONI for host galaxies at z_abs~1 than for systems at z_abs~2. Using the NII/H-alpha ratio, we can thus compare absorption and emission metallicities in the same high-redshift objects, more than doubling the number of systems for which such measures are possible.