Assigned ID: 44 ----- Submission 1 (Wed Jan 19 19:24:26 GMT 2005) ----- We will analyze the IGM enrichment history at z<1.5 by surveying CIV, SiIV, and OVI absorption in HST/STIS E140M and E230M archival spectra. Current results on low-z IGM enrichment are based primarily on OVI and CIV surveys from the HST Key Project FOS data. The archival STIS spectra have >20x higher resolution and correspondingly >10x higher sensitivity to metal-line absorption. With this program, we will investigate the mass density of CIV, OVI and SiIV gas and infer the metallicity of the IGM. In so doing, we will examine the enrichment history over the past 10 Gyr (which includes the peak in the cosmological star formation history), as well as provide a zero-point for comparisons against measurements at z>2. We will also study the intensity and nature of the low-z extragalactic UV background, and measure the galaxy/absorber cross-correlation function for a subset (~15) of the sightlines. Altogether, this program will provide key constratins on metal production and transport processes including galactic winds, pregalactic enrichment, and AGN outflows.

QUASAR ABSORPTION LINES AND IGM 12 112000 false 0.0 false false false false false SUPPORTED