Reference : Polarization properties of a sample of broad absorption line and gravitationally lensed ...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/3891
Polarization properties of a sample of broad absorption line and gravitationally lensed quasars
English
Hutsemekers, Damien mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
Lamy, H. [Institut d'Astrophysique, Universitede Liege, 5 av. de Cointe, B-4000 Liege, Belgium]
Remy, M. [ > > ]
1-Dec-1998
Astronomy and Astrophysics
EDP Sciences
340
371-380
Yes (verified by ORBi)
International
0004-6361
1432-0746
Les Ulis
France
[en] POLARIZATION ; GALAXIES: QUASARS: ABSORPTION LINES ; GALAXIES: QUASARS: GENERAL ; COSMOLOGY: GRAVITATIONAL LENSING
[en] New broad-band linear polarization measurements have been obtained for a sample of 42 optically selected QSOs including 29 broad absorption line (BAL) QSOs. The polarization properties of different sub-classes have been compared, and possible correlations with various spectral indices searched for. The main results of our study are: (1) Nearly all highly polarized QSOs of our sample belong to the sub-class of BAL QSOs with low-ionization absorption features (LIBAL QSOs). (2) The range of polarization is significantly larger for LIBAL QSOs than for high-ionization (HI) BAL QSOs and non-BAL QSOs. (3) There is some indication that HIBAL QSOs as a class may be more polarized than non-BAL QSOs and therefore intermediate between LIBAL and non-BAL QSOs, but the statistics are not compelling from the sample surveyed thus far. (4) For LIBAL QSOs, the continuum polarization appears significantly correlated with the line profile detachment index, in the sense that LIBAL QSOs with P Cygni-type profiles are more polarized. No correlation was found with the strength of the low- or the high-ionization absorption features, nor with the strength or the width of the emission lines. These results are consistent with a scenario in which LIBAL QSOs constitute a different class of radio-quiet QSOs with more absorbing material and more dust. Higher maximum polarization can therefore be reached, while the actually measured polarization depends on the geometry and orientation of the system as do the line profiles. The observed correlation is interpreted within the framework of recent ``wind-from-disk'' models. Tables~2 and 3 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html}\fnmsep\thanks{Based on observations collected at the European Southern Observatory (ESO, La Silla)
http://hdl.handle.net/2268/3891
http://adsabs.harvard.edu/abs/1998A%26A...340..371H
The authors thank EDP Sciences and NASA ADS for their deposit authorization

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