Volume 457, Number 2, October II 2006
|Page(s)||L17 - L20|
|Published online||12 September 2006|
Letter to the Editor
The small dispersion of the mid IR – hard X-ray correlation in active galactic nuclei
European Southern Observatory, Casilla 19001, Santiago 19, Chile e-mail: email@example.com
2 Zentrum für Astronomie, ITA, Universität Heidelberg, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany
3 Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
4 Steward Observatory, The University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721, USA
Accepted: 27 July 2006
Context.We investigate mid-infrared and X-ray properties of the dusty torus in unification scenarios for active galactic nuclei.
Aims.We use the relation between mid IR and hard X-ray luminosities to constrain AGN unification scenarios.
Methods.With VISIR at the VLT, we have obtained the currently highest angular resolution ( FWHM) narrow-band mid infrared images of the nuclei of 8 nearby Seyfert galaxies. Combining these observations with X-ray data from the literature we study the correlation between their mid IR and hard X-ray luminosities.
Results.We find that the rest frame m () and 2–10 keV () luminosities are correlated at a highly significant level. The best fit power-law to our data is , showing a much smaller dispersion than earlier studies.
Conclusions.The similarity in the / ratio between Sy1s and Sy2s even using high angular resolution MIR data implies that the similarity is intrinsic to AGN and not caused by contamination from extra-nuclear emission. This supports clumpy torus models. The exponent of the correlation constrains the inner geometry of the torus.
Key words: galaxies: active / infrared: galaxies / X-rays: galaxies
© ESO, 2006
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.