The Highly Variable Absorber of NGC 4507
Abstract
Variability studies of the X-ray absorbing media in Seyfert galaxies has proved to be a fundamental tool to assess the nature and location of the absorbing matter present in the central region of Active Galactic Nuclei. An exciting recent development is the finding that the X-ray spectra of a few obscured AGN change between characteristically Compton-thin and Compton-thick states on relatively short time scales with the most extreme example being NGC1365. This places severe constraints on the geometry and structure of the X-ray absorbing/reprocessing regions and suggests the presence of apparently multiple absorbers/ reflecting mirrors and that the absorber could be inhomogeneous and could have a range of ionization states. We present the Suzaku observation of the Seyfert 1.9 galaxy NGC4507, one of the X-ray brightest Compton-thin Seyfert 2s and a candidate for a variable absorber. Suzaku caught the source in a reflection dominated state. A comparison with previous X-ray observations shows that NGC4507 changes from transmission to reflection dominated. The pattern of this dramatic spectral variability cannot be simply explained purely by variability of the nuclear activity, but also requires strong variability in the amount of absorption.
- Publication:
-
AAS/High Energy Astrophysics Division #11
- Pub Date:
- March 2010
- Bibcode:
- 2010HEAD...11.0828B