In recent years, several Seyfert 2 galaxies have been discovered that change state when observed in X-rays a few years apart, switching from Compton-thin to reflection-dominated or viceversa. We observed a member of this class of "Changing-look" sources, the Phoenix Galaxy, with Suzaku, with the aim of better understanding the nature of the variations. The Suzaku spectrum was analyzed, and the results compared with previous ASCA and XMM-Newton observations. The source was caught in a Compton-thin state, as in XMM-Newton, but differently from ASCA. Comparing the Suzaku and XMM-Newton observations, a variation in the column density of the absorber on a time scale of years is discovered. A similar change, but on much shorter time scales (i.e. ks) may also explain the count-rate variations during the Suzaku observations. A soft excess is also present, likely due to continuum and line emission from photoionized circumnuclear matter.
@article{arxiv.0902.0930,
title = {Suzaku observation of the Phoenix Galaxy},
author = {G. Matt and S. Bianchi and H. Awaki and A. Comastri and M. Guainazzi and K. Iwasawa and E. Jimenez-Bailon and F. Nicastro},
journal= {arXiv preprint arXiv:0902.0930},
year = {2009}
}
Comments
Accepted for publication in Astronomy & Astrophysics