EPJ Web of Conferences
Volume 39, 2012Tidal Disruption Events and AGN Outbursts
|Number of page(s)||4|
|Section||AGN Outbursts and Accretion Physics|
|Published online||18 December 2012|
Exceptional AGN long-timescale X-ray variability: The case of PHL 1092
1 Centro de Astrobiología (CSIC–INTA), Dep. de Astrofísica; ESA, PO Box 78, 28691 Villanueva de la Cañada, Madrid
2 Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab., Univeristy Park, PA 16802, USA
3 Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
4 Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
5 Department of Astronomy & Physics, Saint Mary’s University, 923 Robie Street, Halifax, NS B3H 3C3, UK
6 Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany
a e-mail: firstname.lastname@example.org
PHL 1092 is a z ∼ 0.4 high-luminosity counterpart of the class of Narrow–Line Seyfert 1 galaxies. In 2008, PHL 1092 was found to be in a remarkably low X-ray flux state during an XMM–Newton observation. Its 2 keV flux density had dropped by a factor of ∼ 260 with respect to a previous observation performed 4.5 yr earlier. The UV flux remained almost constant, resulting in a significant steepening of the optical-to-X-ray slope αox from − 1.57 to − 2.51, making PHL 1092 one of the most extreme X-ray weak quasars with no observed broad absorption lines (BALs) in the UV. We have monitored the source since 2008 with three further XMM–Newton observations, producing a simultaneous UV and X-ray database spanning almost 10 yr in total in the activity of the source. We present here results from our monitoring campaign.
© Owned by the authors, published by EDP Sciences, 2012
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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.