EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 442/1 Article
Free access article

Issue A&A
Volume 442, Number 1, October IV 2005
Page(s) 97 - 107
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20053325



A&A 442, 97-107 (2005)
DOI: 10.1051/0004-6361:20053325

Polarization microvariability of BL Lacertae objects

I. Andruchow1, 2, G. E. Romero1, 2 and S. A. Cellone2

1  Instituto Argentino de Radioastronomía, C.C.5, (1894) Villa Elisa, Buenos Aires, Argentina
    e-mail: andru@irma.iar.unlp.edu.ar
2  Facultad de Ciencias Astronómicas y Geofísicas UNLP, Paseo del Bosque, B1900FWA La Plata, Argentina

(Received 27 April 2005 / Accepted 10 June 2005)

Abstract
We present the results of a systematic observational campaign designed to search for microvariability in the optical polarization of BL Lac objects. We observed a sample formed by 8 X-ray-selected and 10 radio-selected sources, looking for rapid changes in both the degree of linear polarization and the corresponding polarization angle. The whole campaign was carried out during the last three years, and most of the objects were observed on at least two consecutive nights. The statistical properties of both classes of BL Lac objects are compared, and some general conclusions on the nature of the phenomenon are drawn. In general, radio selected sources seem to display higher duty cycles for polarimetric microvariability and, on average, they have a stronger polarization.


Key words: galaxies: active -- galaxies: BL Lacertae objects: general -- polarization

SIMBAD Objects



© ESO 2005


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.