Discovery of a Galaxy Responsible for a DLA System atz = 3 : 15 and a Near -

We report the detection, both in line and continuum emission, of a galaxy responsible for a damped Ly absorption (DLA) system at z = 3:15 projected 2:3 00 from QSO 2233+131. The star formation rate implied by both the Ly and restframe far-UV continuum is 7 M yr ?1. The galaxy also shows no sign of an active nucleus and has blue colors, both consistent with it being observed early in its star formation history. The Ly emission is ooset 200 km s ?1 from the DLA velocity, which could be explained as the rotational signature of a disk galaxy. We also report on the progress of an ongoing near-infrared narrow-band search with the Keck telescope for line emission from a population of primeval galaxies at high redshift. We have found several promising candidates which are being followed up with optical spectroscopy. Our survey is beginning to place constraints on a possible population of slightly dusty primeval galaxies at high redshift. Damped Lyman-alpha absorber (DLA) systems, detected along lines of sight to unrelated high-redshift quasars, have been proposed as possible progenitors of normal disk galaxies today. They appear to contain a substantial fraction of the baryons known to exist in normal galaxies today (Lanzetta, Wolfe, & Turnshek 1995). Several searches for the galaxies responsible for various DLA systems have resulted in a few detections of emission{line galaxies (Lowenthal et all appear either to be AGN or are at a similar redshift as the QSO, suggesting that the source of their ionization may not be a result of star formation. We report on the detection of an object, designated DLA 2233+131, responsible for a previously known DLA system at z abs 1 Figure 1. The spectra of QSO 2233+131 top] and DLA 2233+131 bottom]. The DLA is seen in emission 2:3 00 projected from the QSO. The DLA shows emission from Ly at z = 3:1530, and no signs of higher-ionization lines that would be expected for an active nucleus. 1985). It was found serendipitously during observations of a candidate for a different DLA system in the same eld. The object was also selected independently as a DLA candidate on the basis of its broad-band colors by Steidel, Pettini, & Hamilton (1995), which was unknown to us at the time. We obtained direct images of the eld in the V C and R C bands, and long-slit spectra using low and …