Falcke et al., Radio-Variability in Radio-Quiet Quasars and Low-Luminosity AGN

Radio-Variability in Radio-Quiet Quasars and Low-Luminosity AGN

Falcke H.1, Lehár J.2, Barvainis R.3, Nagar N.M4,5, Wilson A.S.4

1Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany (hfalcke@mpifr-bonn.mpg.de)
2Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138
3National Science Foundation, 4201 Wilson Boulevard, Arlington, VA 22230 (rbarvai@nsf.gov)
4Dept. of Astronomy, University of Maryland, College Park, MD 20742-2421, USA (wilson,neil@astro.umd.edu)
5Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Florence, Italy

in: "Probing the Physics of Active Galactic Nuclei by Multiwavelength Monitoring", eds. B.M. Peterson, R.S. Polidan, R.W. Pogge, ASP Conf. Ser. Vol. 224, p. 265 (2001)


We report on two surveys of radio-weak AGN to look for radio variability. We find significant variability with an RMS of 10-20% on a timescale of months in radio-quiet and radio-intermediate quasars. This exceeds the variability of radio cores in radio-loud quasars (excluding blazars), which vary only on a few percent level. The variability in radio-quiet quasars confirms that the radio emission in these sources is indeed related to the AGN. The most extremely variable source is the radio-intermediate quasar III Zw 2 which was recently found to contain a relativistic jet. In addition we find large amplitude variabilities (up to 300% peak-to-peak) in a sample of nearby low-luminosity AGN, Liners and dwarf-Seyferts, on a timescale of 1.5 years. The variability could be related to the activity of nuclear jets responding to changing accretion rates. Simultaneous radio/optical/X-ray monitoring also for radio-weak AGN, and not just for blazars, is therefore a potentially powerful tool to study the link between jets and accretion flows.

Paper: Available in full length as PostScript and LaTex Format.

Other publications can be found here.

Questions: Heino Falcke, hfalcke@mpifr-bonn.mpg.de