MNRAS-2006-North-1057-66.pdf (884.02 kB)
Download file

A new sample of broad absorption-line quasars exhibiting the ghost of Lyman α

Download (884.02 kB)
journal contribution
posted on 24.10.2012, 09:15 by M. North, C. Knigge, M. Goad
We have searched the broad absorption-line quasar (BAL QSO) sample presented recently by Reichard et al. for objects exhibiting the so-called ‘ghost of Lyman α’. This ghost manifests as a hump near −5900 km s−1 in the troughs of the broad absorption lines and provides strong evidence for the importance of line driving in powering the outflows from BAL QSOs. Of the 224 sample BAL QSOs selected from the Sloan Digital Sky Survey Early Data Release, 198 satisfy our redshift constraints and 58 show clear evidence of multiple-trough (MT) structure in the C iv 1550 Å line. A composite spectrum constructed from this MT sample already shows evidence for a ghost feature. Narrowing our classification scheme further, we define a set of 36 objects that individually show evidence of a ghost feature, and then apply further cuts to arrive at a final ‘best sample’ that contains our seven strongest ghost candidates. A further five objects show evidence for a ghost feature that is almost strong enough to merit inclusion in our best sample. Despite its limited size, our best sample more than doubles the number of known BAL QSOs with clear ghost signatures and should make an excellent basis for detailed follow-up studies.

History

Citation

Monthly Notices of the Royal Astronomical Society, 2006, 365 (4), pp. 1057-1066

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Royal Astronomical Society (RAS)

issn

0035-8711

eissn

1365-2966

Copyright date

2005

Available date

24/10/2012

Publisher version

http://mnras.oxfordjournals.org/content/365/4/1057

Language

en

Usage metrics

Categories

Keywords

Exports