Absorption Lines and Galaxies toward PKS 0312-77

Sarah Giandoni

We studied the Lyman alpha absorbing gas and galaxies connection with a survey of the PKS 0312-77 line of sight using HST spectra and images and ground based spectra and images. We found that Lyman alpha clouds appear to be associated with galaxies that are close to them. We found clusters of galaxies in which three of the four had Lyman alpha gas at similar redshifts. The fourth cluster at redshift z=0.05 was the notable exception. We also compared the Lyman limit system we found at z=0.2026, called G216, to the Galactic/SMC systems. We found both systems to have similar velocity widths of 60 km/s in OVI absorption, indicating that both systems have kinematic broadening in addition to any thermal broadening. We performed GIM2D modeling of G216 and found that the galaxy has a similar disk scale length as The Galaxy, but half the bulge, half-light radius, and luminosity. The kinematic structure of the gas associated with G216 is similar to the Galactic system, but if the G216 systems has an SMC type companion, it would be located on top of the quasar. This is possible, however, due to the fact that the physical distance between G216 and the quasar line of sight is the same as that between the Galaxy and the SMC.