Reverberation mapping of the central regions of active galactic nuclei using high-energy γ-ray observations
نویسندگان
چکیده
We calculate the timeand energy-dependent opacity of high-energy γ-rays attenuated by pairproduction interactions with accretion-flare photons that are scattered by gas and dust surrounding the nuclei of active galaxies. We show that the temporal behavior of the high-energy opacity cutoff can be used in conjunction with the time history of the accretion flare to determine the location of the γ-ray emission site, as well as the column density and scale height of the material surrounding the central engine. Reverberation mapping using this technique is now possible for nearby BL Lac objects such as Mrk 421, and will be particularly valuable when the 10 GeV – 100 GeV γ-ray window is opened, because here the attenuation of distant blazar radiation by the intergalactic infrared background radiation is negligible.
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