H E ] 9 M ar 2 01 0 NGC 2992 in an X-ray high state observed by XMM-Newton : Response of the Relativistic Fe K α Line to the Continuum

We present the analysis of an XMM-Newton observation of the Seyfert galaxy NGC 2992. The source was found in its highest level of X-ray activity yet detected, a factor ∼ 23.5 higher in 2–10 keV flux than the historical minimum. NGC 2992 is known to exhibit X-ray flaring activity on timescales of days to weeks, and the XMM-Newton data provide at least factor of ∼ 3 better spectral resolution in the Fe K band than any previously measured flaring X-ray state. We find that there is a broad feature in the ∼ 5− 7 keV band which could be interpreted as a relativistic Fe Kα emission line. Its flux appears to have increased in tandem with the 2–10 keV continuum when compared to a previous Suzaku observation when the continuum was a factor of ∼ 8 lower than that during the XMM-Newton observation. The XMM-Newton data are consistent with the general picture that increased X-ray activity and corresponding changes in the Fe Kα line emission occur in the innermost regions of the putative accretion disk. This behavior contrasts with the behavior of other AGN in which the Fe Kα line does not respond to variability in the X-ray. Subject headings: galaxies: active galaxies: Seyfert line: profiles X-ray: galaxies X-rays: individual (NGC 2992) Center for Astrophysics, University of Science and Technology of China, Hefei, Anhui 230026, China. xwshu@mail.ustc.edu.cn Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street., Baltimore, MD 21218, USA. yaqoob@skysrv.pha.jhu.edu Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA. Massachusetts Institute of Technology, Center for Space Research, NE80−6013, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. X-ray Astronomy Group, Department of Physics and Astronomy, Leicester University, Leicester, LE1 7RH, UK. Key Laboratory for Research in Galaxies and Cosmology, University of Sciences and Technology of China, Chinese Academy of Sciences