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X-ray and radio variability in the low-luminosity active galactic nucleus NGC 7213
- Source :
- Monthly Notices of the Royal Astronomical Society. 411:402-410
- Publication Year :
- 2010
- Publisher :
- Oxford University Press (OUP), 2010.
-
Abstract
- We present the results of a ~ 3 year campaign to monitor the low luminosity active galactic nucleus (LLAGN) NGC 7213 in the radio (4.8 and 8.4 GHz) and X-ray bands (2-10 keV). With a reported X-ray Eddington ratio of 7 x 10^-4 L_Edd, NGC 7213 can be considered to be comparable to a hard state black hole X-ray binary. We show that a weak correlation exists between the X-ray and radio light curves. We use the cross-correlation function to calculate a global time lag between events in the X-ray and radio bands to be 24 +/- 12 days lag (8.4 GHz radio lagging X-ray), and 40 +/- 13 days lag (4.8 GHz radio lagging X-ray). The radio-radio light curves are extremely well correlated with a lag of 20.5 +/- 12.9 days (4.8 GHz lagging 8.4 GHz). We explore the previously established scaling relationship between core radio and X-ray luminosities and black hole mass L_{R} \propto M^{0.6-0.8} L_{X}^{0.6}, known as the `fundamental plane of black hole activity', and show that NGC 7213 lies very close to the best-fit `global' correlation for the plane as one of the most luminous LLAGN. With a large number of quasi-simultaneous radio and X-ray observations, we explore for the first time the variations of a single AGN with respect to the fundamental plane. Although the average radio and X-ray luminosities for NGC 7213 are in good agreement with the plane, we show that there is intrinsic scatter with respect to the plane for the individual data points.
- Subjects :
- Physics
Active galactic nucleus
Plane (geometry)
Astrophysics::High Energy Astrophysical Phenomena
Binary number
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Light curve
Radio spectrum
Luminosity
Black hole
Space and Planetary Science
Fundamental plane (elliptical galaxies)
Astrophysics::Galaxy Astrophysics
Subjects
Details
- ISSN :
- 00358711
- Volume :
- 411
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Accession number :
- edsair.doi...........159a77ba17d28a37a8f68ca75fe07b8c