AAS 196th Meeting, June 2000
Session 16. Galaxies and Quasars
Oral, Monday, June 5, 2000, 2:00-3:30pm, Lilac Ballroom

[Previous] | [Session 16] | [Next]

[16.06] Chandra HETG Observations of Seyfert Galaxy NGC 4151-- The Narrow-Line Region Viewed in X-rays

P. M. Ogle, H. L. Marshall, J. C. Lee, C. R. Canizares (MIT/CXC)

We report on the X-ray spectrum and structure of the Seyfert 1.5 active galaxy NGC 4151, observed with the Chandra High Energy Transmission Grating. We see over 50 emission lines from high-ionization species, including N VII, hydrogen-like and helium-like O, Ne, Mg, Al, Si, S, and Ar, and Fe XVII-XX. We confirm that the low-energy (E<2.5 keV) emission is extended (Morse et al. 1995) and further find a correspondence on arcsecond scales to the optical narrow-line region. The hard continuuum source (E>2.5 keV) is point-like and was in an unusually low state during our observation.

The dispersed spectrum is fit by highly absorbed non-thermal (power-law) emission from the central point source plus lines and continuum scattered by the extended photoionized nebula. Photoionization is clearly required by the large ratio of forbidden to resonance emission in O VII. Spatial broadening is seen in the X-ray emission lines, showing that they come from a region at least 2.5 arcsec in diameter. Differences in the the redshifts as well as ionization states of the X-ray and optical lines suggest that though the X-ray and optical line-emitting regions appear to be spatially coincident, they constitute two distinct components within the narrow-line region. This work was funded in part by contracts NAS8-38249 and SAO SV1-61010.

If you would like more information about this abstract, please follow the link to http://space.mit.edu/~pmo/Welcome.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: pmo@space.mit.edu

[Previous] | [Session 16] | [Next]