Astron. Astrophys. 358, 835-840 (2000)

The optical polarization of radio-loud and radio-intermediate broad absorption line quasi-stellar objects ^*

D. Hutsemékers ^{**  1,2} and H. Lamy <sup>2

1</sup> European Southern Observatory, Casilla 19001, Santiago 19, Chile
² Institut d'Astrophysique, Université de Liège, 5 av. de Cointe, 4000 Liège, Belgium

Received 6 January 2000 / Accepted 14 April 2000

Abstract

On the basis of a sample of approximately 50 broad absorption line quasi-stellar objects (BAL QSOs), we investigate possible correlations between BAL QSO radio properties and other spectral characteristics, including polarization. For this purpose new polarization data have been obtained.

The main result of our statistical study is the absence of significant correlations between the radio-to-optical flux ratio and all other quantities: the polarization of the continuum, the slope of the continuum, the balnicity and detachment indices which characterize the BAL profiles, and the terminal velocity of the flow . The claimed anticorrelation between and is therefore not confirmed, as well as the correlation between and predicted by some models. Although marginally significant, the only possible correlations occur for the BAL QSOs with low-ionization troughs.

Key words: galaxies: quasars: absorption lines galaxies: quasars: general polarization

* Based on observations collected at the European Southern Observatory (ESO, La Silla)
** Also, Chercheur Qualifié au Fonds National de la Recherche Scientifique (FNRS, Belgium)

SIMBAD Objects

Contents

• 1. Introduction
• 2. The data
  • 2.1. The radio data
  • 2.2. The polarization
  • 2.3. The spectral indices
  • 2.4. The LIBAL / HIBAL classification
• 3. Results of statistical tests
• 4. Discussion and conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: June 20, 2000
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