An Imaging and Spectroscopic Study of thezabs = 3.38639 Damped Lyα System in Q0201+1120: Clues to Star Formation at High Redshift

We present the results of a series of imaging and spectroscopic observations aimed at identifying and studying the galaxy responsible for the z abs = 3.38639 damped Lyα system in the z em = 3.61 quasar Q0201+1120. We find that the damped Lyα systems (DLA) is part of a concentration of matter that includes at least four galaxies (probably many more) over linear comoving dimensions greater than 5 h -1 Mpc. The absorber may be a 0.7 L * galaxy at an impact parameter of 15 h -1 kpc, but follow-up spectroscopy is still required for positive identification. The gas is turbulent, with many absorption components distributed over ~270 km s -1 and a large spin temperature, T s ≳ 4000 K. The metallicity is relatively high for this redshift, Z DLA ≃ 1/20 Z ☉ . From consideration of the relative ratios of elements that have different nucleosynthetic timescales, it would appear that the last major episode of star formation in this DLA occurred at z ≳ 4.3, more than ~500 Myr prior to the time when we observe it.