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Session 20 - QSOs.
Oral session, Monday, January 13
Frontenac Ballroom,

[20.03] HST Imaging of Quasar Host Galaxies

E. J. Hooper, C. D. Impey (Steward Obs.), C. B. Foltz (Multiple Mirror Telescope Obs.)

A sample of 16 quasars from the Large Bright Quasar Survey (LBQS) has been imaged with WFPC2 on the Hubble Space Telescope. The sample was selected to cover a range of radio luminosity typical of optically selected quasars in narrow intervals of redshift (0.4 \leq z \geq 0.5) and absolute magnitude (-25 < M_B < -23). Two-dimensional cross-correlation techniques were used to determine the magnitudes of the host galaxies and quasar nuclear components, as well as the axial ratios of the hosts.

The derived host galaxy magnitudes are near or below L^* and are correlated with the quasar nuclear magnitude, similar to the trend in near-infrared host galaxy luminosity found by McLeod amp; Rieke (1995, ApJ, 454, L77). There is no discernable difference in host galaxy luminosity between radio-loud and radio-quiet quasars in the sample. Preliminary analysis of the host galaxy morphologies indicates that many, including several of the radio-quiet quasars, are probably in early type galaxies, consistent with other high-resolution imaging studies of quasar hosts. However, the distribution of axial ratios is not consistent with a population of early type galaxies. The hosts in the LBQS sample are rather flattened, with half having axial ratios \leq 0.5. It is possible that these are inclined disk systems or galaxies with substantial bar components.

Program listing for Monday