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Updated: Aug 19, 2026

Cerenkov Luminescence Imaging of Interscapular Brown Adipose Tissue
Published on: October 7, 2014
Possible Evidence for Truncated Thin Disks in the Low-Luminosity Active Galactic Nuclei M81 and NGC 4579
Abstract:
M81 and NGC 4579 are two of the few low-luminosity active galactic nuclei that have an estimated mass for the central black hole, detected hard X-ray emission, and detected optical/UV emission. In contrast to the canonical "big blue bump," both have optical/UV spectra that decrease with increasing frequency in a nuLnu plot. Barring significant reddening by dust and/or large errors in the black hole mass estimates, the optical/UV spectra of these systems require that the inner edge of a geometrically thin, optically thick accretion disk lies at approximately 100 Schwarzschild radii. The observed X-ray radiation can be explained by an optically thin, two-temperature, advection-dominated accretion flow at smaller radii.
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