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Quasar damped Ly-alpha (DLA) absorption line systems with redshifts z<1.65are used to trace neutral gas over approximately 70 per cent of the most recenthistory of the Universe. However, such systems fall in the UV and are rarelyfound in blind UV spectroscopic surveys. Therefore, it has been difficult tocompile a moderate-sized sample of UV DLAs in any narrow cosmic time interval.However, DLAs are easy to identify in low-resolution spectra because they havelarge absorption rest equivalent widths. We have performed an efficientstrong-MgII-selected survey for UV DLAs at redshifts z=[0.42,0.70] using HST'slow-resolution ACS-HRC-PR200L prism. This redshift interval covers ~1.8 Gyr incosmic time, i.e., t~[7.2,9.0] Gyrs after the Big Bang. A total of 96 strongMgII absorption-line systems identified in SDSS spectra were successfullyobserved with the prism at the predicted UV wavelengths of Ly-alpha absorption.We found that 35 of the 96 systems had a significant probability of being DLAs.One additional observed system could be a very high N(HI) DLA (N(HI)~2x10^22atoms cm^-2 or possibly higher), but since very high N(HI) systems areextremely rare, it would be unusual for this system to be a DLA given the sizeof our sample. Here we present information on our prism sample, including ourbest estimates of N(HI) and errors for the 36 systems fitted with dampedLy-alpha profiles. This list is valuable for future follow-up studies oflow-redshift DLAs in a small redshift interval, although such work wouldclearly benefit from improved UV spectroscopy to more accurately determinetheir neutral hydrogen column densities.

Thirty-six New, High-Probability, Damped Ly-alpha Absorbers at Redshift 0.42 < z < 0.70