The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. http://dspace-roma3.caspur.it:80 2013-05-23T15:45:27Z 2013-05-23T15:45:27Z Matt, Giorgio Bianchi, Stefano Awaki, Hisamitsu Comastri, Andrea Guainazzi, Matteo Iwasawa, Kazushi Jimenez-Bailon, Elena Nicastro, Fabrizio http://hdl.handle.net/2307/286 2011-12-22T13:35:28Z 2009-02-28T23:00:00Z

<Title>Suzaku observation of the Phoenix galaxy</Title> <Authors>Matt, Giorgio; Bianchi, Stefano; Awaki, Hisamitsu; Comastri, Andrea; Guainazzi, Matteo; Iwasawa, Kazushi; Jimenez-Bailon, Elena; Nicastro, Fabrizio</Authors> <Issue Date>2009-03</Issue Date> <Is part of>Astronomy & Astrophysics</Is part of> <Volume>496</Volume> <Pages>653-658</Pages> <Abstract>Context. In recent years, several Seyfert 2 galaxies have beendiscovered that change state when observed in X-rays a few years apart,switching from Compton-thin to reflection-dominated or viceversa.Aims. We observed a member of this class of "Changing-look" sources,the Phoenix galaxy, with Suzaku, with the aim of better understandingthe nature of the variations.Methods. The Suzaku spectrum was analyzed, and the results comparedwith previous ASCA and XMM-Newton observations.Results. The source was caught in a Compton-thin state, as inXMM-Newton, but differently from ASCA. Comparing the Suzaku andXMM-Newton observations, a variation in the column density of theabsorber on a time scale of years is discovered. A similar change, buton much shorter time scales (i.e. ks) may also explain the count-ratevariations during the Suzaku observations. A soft excess is alsopresent, likely due to continuum and line emission from photoionizedcircumnuclear matter.</Abstract>

2009-02-28T23:00:00Z