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X-ray dips in the seyfert galaxy fairall 9: Compton-thick "cOMETS" or a failed radio galaxy?

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Lohfink, AM 
Reynolds, CS 
Mushotzky, RF 
Wilms, J 

Abstract

We investigate the spectral variability of the Seyfert galaxy Fairall 9 using almost 6 years of monitoring with the Rossi X-ray Timing Explorer (RXTE) with an approximate time resolution of 4 days. We discover the existence of pronounced and sharp dips in the X-ray flux, with a rapid decline of the 2--20 keV flux of a factor 2 or more followed by a recovery to pre-dip fluxes after ~10 days . These dips skew the flux distribution away from the commonly observed log-normal distribution. Dips may result from the eclipse of the central X-ray source by broad line region (BLR) clouds, as has recently been found in NGC 1365 and Mrk 766. Unlike these other examples, however, the clouds in Fairall 9 would need to be Compton-thick, and the non-dip state is remarkably free of any absorption features. A particularly intriguing alternative is that the accretion disk is undergoing the same cycle of disruption/ejection as seen in the accretion disks of broad line radio galaxies (BLRGs) such as 3C120 but, for some reason, fails to create a relativistic jet. This suggests that a detailed comparison of Fairall 9 and 3C120 with future high-quality data may hold the key to understanding the formation of relativistic jets in AGN.

Description

Keywords

galaxies: individual (Fairall 9), galaxies: nuclei, galaxies: Seyfert, X-rays: galaxies

Journal Title

Astrophysical Journal Letters

Conference Name

Journal ISSN

2041-8205
2041-8213

Volume Title

749

Publisher

American Astronomical Society
Sponsorship
National Aeronautics and Space Administration (NNX10AR31G)