AAS 196th Meeting, June 2000
Session 50. Active Galaxies
Display, Thursday, June 8, 2000, 9:20am-4:00pm, Empire Hall South

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[50.08] Narrow Absorption Lines in Moderate-Redshift Quasars

M. Vestergaard (OSU), L.C. Ho (OCIW)

We use a large, high-quality spectral data base of well-selected, moderate-redshift quasars to characterize the incidence of narrow associated C\,{\sc iv} \lambda\,1549 absorption, and how this may depend on some quasar properties.

Associated narrow absorption lines (NALs) in active galaxies have widths less than a few hundred km\,s-1 and are located within ±5000\,km\,s-1 of the emission redshift. They are likely physically connected to the active galactic nucleus and are possibly the low-velocity equivalents to the more dramatic broad absorption features (BALs), with line widths reaching tens of thousands of km\,s-1. The current physical interpretation is that the line widths of both NALs and BALs trace the outflow velocity of the absorbing gas and that these outflows are somewhat equatorial. The exact solid angle extension of the NAL and BAL matter above the disk is unknown.

BALs are predominantly found in the high-luminosity, radio-quiet quasars with a frequency of 10--12%. NALs appear present in 50--70% of the low-luminosity Seyfert galaxies, yet the frequency in quasars and how it may depend on source radio power and source axis inclination are unknown. We will address this issue with our large, high-quality, UV spectral data base of z\approx\,2 quasars for which the data are uniformly processed and analyzed. We study the frequency of associated C\,{\sc iv} NALs and test for possible trends with quasar properties, such as luminosity, UV spectral slope, radio loudness, and source inclination.

The author(s) of this abstract have provided an email address for comments about the abstract: vester@astronomy.ohio-state.edu

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