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[78.25] A Census of Intrinsic Narrow Absorption Lines at z~3.0

T. Misawa, M. Eracleous, J. Charlton (Penn State University), R. Ganguly (STScI), D. Tytler, D. Kirkman, J. O'Meara, N. Suzuki, D. Lubin (UCSD)

For the purpose of studying intrinsic narrow absorption lines, we have searched 40 Keck/HIRES spectra of quasars at redshifts between 2 and 4, originally selected to measure D/H in the Lyman-alpha forest. In these spectra, we have identified 259 doublets of SiIV, CIV, and NV, of which 24 are associated (within 5000km/s of the quasar redshift). Since the velocity resolution is ~8km/s, we are using partial coverage to separate intrinsic and intervening absorbers. In our preliminary analysis, a number of excellent candidates have been identified. We evaluated two kinds of fractions, the fraction of quasars whose spectra have associated NALs, and the fraction of the associated NALs that are intrinsic to the quasars. Since not all intrinsic absorbers will necessarily exhibit partial coverage, this will provide a lower limit to the fraction of quasars that have intrinsic narrow absorption lines. Detailed study of these candidates, including observations of variability and photoionization modeling, will yield constraints on the locations and physical properties of the absorbing structures.

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.