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Session 11 - AGN.
Display session, Monday, January 13
We present high resolution (\sim0.6\arcsec) near infrared Keck observations which probe the optically obscured nucleus of NGC 4258 (M 106) which is believed to contain a massive black hole. The images show a compact central source at H (1.65\micron) and K (2.23\micron) after the J (1.23\micron) component, which was taken to be dominated by the bulge stars, was subtracted out. The compact source has a measured K flux of \sim3 mJy and might be marginally resolved. When corrected for A_V\sim20 mag of extinction the IR luminosity (1.5\micron - 3.0\micron) is \sim3\times10^7 L_\sun. The corresponding X-ray (2-10 keV) luminosity is \sim10^7 L_\sun while the central source has been estimated at \sim10^2 L_\sun in the radio. We argue that our near infrared source is a spherical dust shell around the center which is reprocessing the radiation emitted by the black hole inferred to be at the center.
Program listing for Monday