2008/12/02 by W. Ishibashi, T. J. -L. Courvoisier, T. J.-L. Courvoisier
Physics and Astronomy · #Accretion (finance) #Accretion disc #Active galactic nucleus #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Black hole (networking) #Cascade #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Optics #Physics #Spectral line #X-ray #astro-ph
paper · pdf · doi:10.1051/0004-6361:200810043
8 pages, 1 figure, accepted for publication in A&A
arxiv created 2008/12/02 · openalex publication_date 2009/01/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider the fuelling of the central massive black hole in active galactic nuclei (AGN), through an inhomogeneous accretion flow. Performing simple analytical treatments, we show that shocks between elements (clumps) forming the accretion flow may account for the UV and X-ray emission in AGNs. In this picture, a cascade of shocks is expected, where optically thick shocks give rise to optical/UV emission, while optically thin shocks give rise to X-ray emission. The resulting blue bump temperature is found to be quite similar in different AGNs. We obtain that the ratio of X-ray luminosity to UV luminosity is smaller than unity, and that this ratio is smaller in massive objects compared to less massive sources. This is in agreement with the observed ratio and suggests a possible interpretation of the anticorrelation.