Karlsruhe 2011 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 89: Gammaastronomie III

T 89.5: Vortrag

Mittwoch, 30. März 2011, 17:45–18:00, 30.41: 104

Internal γγ-opacity in the Low Luminosity Active Galactic Nuclei M87 and Cen A — •Katharina Brodatzki¹, David Pardy², Julia Becker¹, and Reinhard Schlickeiser¹ — ¹Ruhr-Universität Bochum, Germany — ²Queen’s University, Kingston, Canada

Low Luminosity Active Galactic Nuclei (LLAGNs) possess the characteristic features of more luminous Active Galactic Nuclei (AGNs) but have a much lower optical core luminosity than their luminous counterparts. M87 (NGC 4486) and Centaurus A (NGC 5128, Cen A) are well-known and nearby members of LLAGNs. As an additional feature they show γ-radiation up to TeV (10¹²eV) energies, but the location of the TeV production site is still unclear. The coincident observation of a radio and TeV flare in M87 suggests that the TeV radiation is produced not more than ∼ 100 gravitational radii away from the central supermassive black hole. Since the central region of an (LL)AGN can be the location of several strong radiation fields, it is possible that radiation produced near the black hole is strongly attenuated and therefore not observable at Earth. Here, we consider the accretion flow around the black hole as the most important source for such a radiation field and calculate the probability for absorption of TeV photons produced near the black holes in M87 and Cen A assuming a low luminosity Shakura-Sunyaev Disk (SSD). We find that the results are very different for both LLAGNs implying either that the TeV γ-ray production sites and processes are different for both sources, or that LLAGN black holes do not accrete (at least only) in form of a low luminosity SSD.