In:
International Astronomical Union Colloquium, Cambridge University Press (CUP), Vol. 159 ( 1997), p. 222-223
Abstract:
We suggest that the broad-line regions (BLRs) of QSOs with broad emissionlines (BALs) are expanding, i.e., the clouds are undergoing radial outflow, as illustrated simply in Fig. 1. At least the following observational facts can be explained: 1. Optical observations show that some moderate and high-redshift QSOs have BALs. The number of these QSOs is about 3–10% of all QSOs (Foltz et al. 1990). One can see in Fig. 2 that very low-redshift QSOs have no BALs. 2. Almost all BAL QSOs exhibit z abs 〈 z em . 3. High-resolution observations reveal that the widths of the broad absorption lines are narrower than that of the corresponding emission line for all BAL QSOs, i.e. Δ λ ab 〈 Δ λ em .
Type of Medium:
Online Resource
ISSN:
0252-9211
DOI:
10.1017/S0252921100040112
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
1997
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