X-ray Spectroscopy of Seyfert 2 Galaxies
Abstract
A new, unprecedented era in X-ray spectroscopy has been made possible by the recent launching of the XMM-Newton and Chandra satellites. X-ray spectra, roughly comparable in resolution to optical/UV spectra, have been taken for several Seyfert 2 galaxies, including the brightest one, NGC 1068. Despite the varying optical, UV, and IR spectra of these Seyfert 2, their X-ray spectra appear remarkably similar. Bright, narrow radiative recombination continua provide the ``smoking gun'' for relatively cool, recombining gas photoionized by the nuclear continuum. However, all spectra show deviations from the predicted spectrum of a purely recombining gas. These deviations could be due to significant photoexcitation or a separate, collisionally-driven gas component (e. g., shock-heated gas in starburst regions). The observed anomalous strength of the higher-order ionic transitions provides unambiguous evidence for photoexcitation, whereas iron L-shell transitions provide useful diagnostics for determining the amount of collisionally-driven gas. Given the ability for robust discrimination of emission mechanisms, X-ray spectroscopy is uniquely well suited for probing the possible connection between Active Galactic Nucleus activity and star formation. A. K. would like to acknowledge support from an NSF fellowship.
- Publication:
-
American Astronomical Society Meeting Abstracts #198
- Pub Date:
- May 2001
- Bibcode:
- 2001AAS...198.1706K