WFPC2 Imaging of Quasar Environments: A Comparison of LBQS and HST Archive Quasars

Abstract

Studies of the large-scale environments of quasars provide insight into the role of environment in triggering quasar activity and can be used to corroborate theories of radio power. This paper addresses two main questions. First, have previous quasar environment studies been biased by preferentially studying very strong radio sources or unusual optically selected quasars? Second, are radio-loud quasars located in different environments than radio-quiet quasars? We use HST WFPC2 data to address these questions. To investigate possible biases in quasar sample selection, we compare 16 quasars from the Large Bright Quasar Survey (LBQS) to a sample of quasars drawn from the Hubble Space Telescope (HST) Archive, consisting of mainly PG and PKS quasars. Quasars from the LBQS are representative of the radio-quiet quasar population as a whole and are therefore more likely to reflect the incidence of clustering around quasars in general. To adress the second question, we compare the environmental properties of the radio-loud and radio-quiet quasars within each sample.