M ar 2 01 2 A remarkable long-term light curve , and deep , low-state spectroscopy : Swift & XMM-Newton monitoring of the NLS 1 galaxy Mkn

The Narrow-line Seyfert 1 galaxy (NLS1) Mkn 335 is remarkable because it has repeatedly shown deep, long X-ray low-states which show pronounced spectral structure. It has become one of the prototype AGN in deep minimum X-ray states. Here we report on the continuation of our ongoing monitoring campaign with Swift and the examination of the low state X-ray spectra based on a 200 ks triggered observation with XMM-Newton in June 2009. Swift has continuously monitored Mkn 335 since May 2007 typically on a monthly basis. This is one of the longest simultaneous UV/X-ray light curves so far obtained for an active galactic nucleus (AGN). Mkn 335 has shown strong X-ray variability even on time scales of hours. In the UV, it turns out to be one of the most variable among NLS1s. Long-term Swift monitoring allow us to examine correlations between the UV, X-rays and X-ray hardness ratios. We find no significant correlation or lag between the UV and X-ray variability; however, we do find distinct trends in the behavior of the hardness ratio variability. The hardness ratio and count rate are correlated in the low-flux state, but no correlation is seen in the high-state. The X-ray low-state spectra of the 2007 and 2009 XMM-Newton observations display significant spectral variability. We fit the X-ray spectra with a suite of phenomenological models in order to characterize the data. The broad band CCD spectrum can be fitted equally well with partial absorption and blurred reflection models. These more complicated models are explored in further detail in upcoming work. Subject headings: galaxies: active, galaxies: individual (Mkn 335), galaxies: Seyferts, X-rays: galaxies Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802; grupe@astro.psu.edu Technische Universität München, Fakultät für Physik, James-Franck-Strasse 1/I, D-85748 Garching, Germany; stefanie.komossa@gmx.de Excellence Cluster Universe, TUM, Boltzmannstrasse 2, 85748 Garching, Germany Max Planck Institut für Plasmaphysik, Boltzmannstrasse 2, 85748 Garching, Germany Department of Astronomy and Physics, Saint Mary’s University, Halifax, NS B3H 3C3, Canada; lgallo@ap.stmarys.ca MIT Kavli Institute for Astrophysics and Space Research 77 Massachusetts Avenue, NE80-6011 Cambridge, MA 02139 XMM-Newton Science Operations Centre ESAC, P.O. Box 78 28691 Villanueva de la Cañada, Madrid, Spain Institute of Astronomy, Madingley Road, Cambridge,