EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 425/2 Article
Free access article

Issue A&A
Volume 425, Number 2, October II 2004
Page(s) 405 - 416
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20040546



A&A 425, 405-416 (2004)
DOI: 10.1051/0004-6361:20040546

The impact of thermal gas in AGN jets on the low-frequency emission

M. Siewert1, M. Pohl1, 2 and R. Schlickeiser1

1  Institut für Theoretische Physik, Lehrstuhl IV, Ruhr-Universität Bochum, 44780 Bochum, Germany
    e-mail: ms@tp4.ruhr-uni-bochum.de
2  Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA

(Received 29 March 2004 / Accepted 25 May 2004)

Abstract
We study the effect of non-relativistic, thermal matter in the jets of active galaxies (AGN) on the low-frequency non-thermal emission and the variability thereof. In matter-dominated jets, sizable quantities of gas should exist, in particular in the compression zones near the collision fronts that are an implicit ingredient of Fermi-type particle acceleration scenarios. Non-relativistic thermal gas in AGN jets noticably contributes to the optical depth at radio to infrared frequencies, and much less to the emission, with an efficiency that is strongly temperature-dependent. The observable flux of low-frequency emission is thus modulated by the temperature evolution of the thermal gas, and it can therefore display very complicated variability. For a particular particle energisation scenario we calculate the temperature evolution of the thermal plasma as well as the radiation transport of low-frequency emission, and thus derive simulated light curves at different frequencies and their typical correlation properties.


Key words: galaxies: active -- plasmas

SIMBAD Objects



© ESO 2004


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.