Journal Article

γ-ray variability of radio-loud narrow-line Seyfert 1 galaxies

G. Calderone, L. Foschini, G. Ghisellini, M. Colpi, L. Maraschi, F. Tavecchio, R. Decarli and G. Tagliaferri

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 413, issue 4, pages 2365-2370
Published in print June 2011 | ISSN: 0035-8711
Published online May 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2011.18308.x
γ-ray variability of radio-loud narrow-line Seyfert 1 galaxies

Show Summary Details

Preview

The recent detection of γ-ray emission from four radio-loud narrow-line Seyfert 1 galaxies suggests that the engine driving the active galactic nuclei (AGN) activity of these objects shares some similarities with that of blazars, namely the presence of a γ-ray emitting, variable jet of plasma closely aligned to the line of sight. In this work we analyse the γ-ray light curves of the four radio-loud narrow-line Seyfert 1 galaxies for which high-energy γ-ray emission has been discovered by Fermi/LAT, in order to study their variability. We find significant flux variability in all the sources. This allows us to exclude a starburst origin of the γ-ray photons and confirms the presence of a relativistic jet. Furthermore, we estimate the minimum e-folding variability time-scale (3–30 d) and infer an upper limit for the size of the emitting region (0.2–2 pc, assuming a relativistic Doppler factor δ= 10 and a jet aperture of θ= 0.1 rad).

Keywords: galaxies: individual: PMN J0948+0022; galaxies: individual: 1H 0323+342; galaxies: individual: PKS 1502+036; galaxies: individual: PKS 2004−447; galaxies: jets; gamma-rays: galaxies

Journal Article.  4538 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.