AAS 199th meeting, Washington, DC, January 2002
Session 99. AGN - Narrow Line and Broad Line
Display, Wednesday, January 9, 2002, 9:20am-6:30pm, Exhibit Hall

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[99.08] Ionization Mechanisms of Four LINER 2s

A. Peter (U Washington, Harvard-Smithsonian CfA), A. Zezas, G. Fabbiano (Harvard-Smithsonian CfA)

We present the results from the analysis of \textit{Chandra} observations of a sample of four LINER 2 galaxies (NGC 404, NGC 4261, NGC 4374, NGC 4736), selected from the spectroscopic survey of Ho, Filippenko, and Sargent (1997). We find that the nuclei do not dominate the galactic X-ray emission (contributions ranging from 5% to 29% in the 0.3-7 keV band). This is notable in the case of NGC 4736, for which the nucleus is not even the brightest X-ray point source in the galaxy as also reported by Eracleous et al. (2001). We find spectral evidence that NGC 4261 (nuclear LX\approx7\times1040 ergs/s) and NGC 4374 (nuclear LX\approx 5\times 1039 ers/s) harbor an AGN, and we cannot rule out this possibility for NGC 404 (nuclear LX\approx3\times1037 ergs/s) and NGC 4736 (nuclear LX\approx 5 \times 1038 ergs/s). In particular, the spectrum of the nucleus of NGC4261 suggests that the AGN may be highly obscured. If our sample is representative of the type-2 LINER population, then we expect a significant number of very low luminosity AGN, with important implications for AGN population studies.

Research funded by the NSF through the Research Experiences for Undergraduates (AST-9731923) program and the Chandra X-ray Observatory Center (NAS8-39073).

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