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Session 11 - QSOs and Radio Galaxies.
Display session, Monday, June 08
Atlas Ballroom,

[11.07] Determining the Fraction of Intrinsic Absorption in QSO Absorption Line Systems

G. T. Richards (U. Chicago, Fermilab), D. G. York (U. Chicago)

We present preliminary results of an exhaustive study of QSO Absorption Line Systems (QSOALS) with respect to intrinsic QSO properties using an updated catalog of most of the data in the literature. We have searched the literature for 6 and 20 cm radio flux densities and have studied 20 cm contour plots from the FIRST VLA Survey so that we can compare the absorption properties with radio luminosity, radio spectral index and radio morphology. While the data in our catalog are decidedly heterogeneous, great care has been taken to account for potential biases during the course of our research. Analysis of relatively unbiased subcatalogs allows us to investigate the properties of QSOALS with better statistics than with any single homogeneous catalog. This work focuses particularly on the nature of QSOALS and their distribution in velocity space in light of the intrinsic properties of the QSOs. We find that the distribution of C\,\sc iv absorption systems is dependent not only on the optical luminosity of the QSOs as has been reported previously, but also the radio luminosity, the radio spectral index and the radio morphology of the QSOs. This dependence holds for systems whose velocity with respect to the QSO exceeds 5000\,km/s as well as those within the traditional intrinsic absorption limit of 5000\, km/s. These observations are apparently inconsistent with the hypothesis that these systems are due to intervening galaxies and it would seem that the contamination of intervening systems by those that are intrinsic to the environment of the QSO is significantly larger than has generally been supposed. We stress the need for truly homogeneous and unbiased surveys of QSOALS -- which we feel do not currently exist -- to confirm these results from our inhomogeneous data set.

Program listing for Monday