Seyfert Galaxy Fe K$\alpha$ Lines and the Weakening Accretion Disk Connection
Session 30 -- Seyfert Galaxies
Oral presentation, Wednesday, January 12, 2:15-3:45, Salon IV Room (Crystal Gateway)

## [30.03] Seyfert Galaxy Fe K$\alpha$ Lines and the Weakening Accretion Disk Connection

K. A. Weaver (Penn State U., U. of Maryland, NASA/GSFC)

A combination of archival HEAO-1 A2 data for a sample of 25 Seyfert galaxies and BBXRT data for the well-studied Seyfert galaxy NGC 4151 provides evidence that strong Fe K$\alpha$ lines (equivalent width $>$ 110 eV) are not produced in an accretion disk close to the central source, but instead originate by reprocessing in some other area of the galaxy such as the broad line region. New analysis techniques have resulted in the detection of spectral complexity in the form of Fe K$\alpha$ features and/or high energy ($>$7 keV) spectral flattening in $\sim$75\% of the HEAO-1 sample. This confirms the recent Ginga$result that X-ray spectral complexity is common in Seyfert galaxies. However, the HEAO-1 data indicate that if the high energy flattening is due to Compton reflection from a neutral accretion disk, the amount of reflection generally detected is the maximum amount possible. If we are seeing reprocessing from a disk, then we expect to observe Fe K$\alpha$fluorescence from the disk as well. However, strong Fe K$\alpha$lines are detected in sources that show no evidence of Compton reflection while sources that do show evidence of reflection do not have strong Fe K$\alpha$lines. This result, along with the strong, narrow Fe K$\alpha$line observed in the BBXRT spectrum of NGC 4151 (a source that also does not show a Compton hump), suggests that strong Fe K$\alpha$lines are not associated with accretion disks. Alternatively, when high quality X-ray spectral data is available for more Seyfert galaxies, strong Fe K$\alpha\$ lines'' (as observed with proportional counters) may prove to be complex features with both narrow and broad components. The observational implication of this result is that accretion disk-produced Fe K lines in Seyfert galaxies will be difficult to isolate and study.