Violent Activity in the Seyfert Galaxy NGC 2992: Probing Accretion and Circumnuclear Matter with Suzaku and RXTE
Abstract
Over a quarter of a century of X-ray observations of the Seyfert 1.9 galaxy NGC 2992 show that it is a promising test-bed for severely constraining accretion disk models. We present the results of a 1 year monitoring campaign of the Seyfert 1.9 galaxy NGC 2992 with RXTE that were quasi-simultaneous with three Suzaku observations. The X-ray continuum varied by more than an order of magnitude on a timescale of weeks. The previous interpretation of the historical activity of NGC 2992 in terms of the accretion disk slowly becoming dormant over many years and then `re-building' itself is not supported by the new results.
During the large-amplitude flares the centroid energy of the Fe K emission-line complex became significantly redshifted, indicating that the violent activity was occurring close to the putative central black hole where gravitational energy shifts can be sufficiently large. Moreover, the Suzaku data are able to deconvolve the persistent disk-line emission from the distant-matter Fe K line emission and we discuss the implied constraints on the disk and circumnuclear matter. Even though the line-of-sight column density in NGC 2992 has a Thomson depth <<1, a highly generalized reprocessor model is required to derive meaningful physical parameters of the disk and circumnuclear matter. Such a spectral fitting tool has thus far not been available so we are currently developing one that will be made publicly available.- Publication:
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AAS/High Energy Astrophysics Division #10
- Pub Date:
- March 2008
- Bibcode:
- 2008HEAD...10.2612M