2001/03/31 by B. Grossan, Bruce Grossan, V. Gorjian +5 · 1 citation
Physics and Astronomy · #Active galactic nucleus #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Extinction (optical mineralogy) #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Nucleus #Spectral line #astro-ph
paper · pdf · doi:10.1086/323948
You can get the most current ps copy all in one go at http://panisse.lbl.gov/public/bruce/mirlin.tar.gz . This version has been approved for publication and contains some significant changes
arxiv created 2001/11/01 · openalex publication_date 2001/12/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We observed two nearby galaxies with potential or weak indications of nuclear activity, M32 and M81, with the MIRLIN mid-IR camera at N band (10.79 μm). M32 is not detected, but we give detailed measurements of the nucleus of M81. Our observations of M81 show a bright nuclear point source at N , and comparison to measurements made in the early 1970s gives an increase in nuclear flux of nearly a factor of 2. If the comparison is accurate, the nuclear mid-IR emission must ultimately be powered by a variable, compact source, similar to that in Seyfert galaxies and quasars. M81 has been classified in the literature as a low-luminosity LINER, not a pure Seyfert galaxy. Further, it has been suggested that this and other low-luminosity active galactic nuclei may have intrinsically different spectra than Seyfert galaxies and quasars. However, we find that the relative fluxes in the X-ray, mid-IR, and radio bands, all essentially unaffected by extinction and galaxy pollution, show a nuclear continuum remarkably like that of a bona fide Seyfert galaxy or quasar.