Geological Education in the U.S.S.R.

Active Galactic Nuclei at the Crossroads of Astrophysics

“…5. Spectroscopic studies in the optical [8,58,120,184] infrared [111] radio [104], and increasingly also in the X-ray domain [34,37,115,131,132,135,157,167,187] have provided measurements of the gas and stellar kinematics near the central black hole [189], in the broad and narrow line regions of galactic nuclei. These studies will be greatly enhanced with the systematic spectroscopy provided by the SDSS data and with the high-energy spectroscopy data from the existing and planned X-ray missions.…”

Extragalactic Relativistic Jets and Nuclear Regions in Galaxies

“…A number of recent studies have used jets to probe physical conditions in the central regions of AGN. Opacity and absorption in the nuclear regions of AGN have been probed effectively using the non-thermal continuum emission as a background source [21]. The free-free absorption studies indicate the presence of dense, ionized circumnuclear material with T e ≈ 10 4 K distributed within a fraction of parsec from the central nucleus [19,42].…”

“…Substantial progress achieved during the past decade in studies of active galactic nuclei (see [25] for a review of recent results) has brought an increasingly wider recognition of the ubiquity of relativistic outflows (jets) in galactic nuclei [5,43] turning them into an effective probe of nuclear regions in galaxies [21]. Emission properties, dynamics, and evolution of an extragalactic jet are intimately connected to the characteristics of the supermassive black hole, accretion disk and broad-line region in the nucleus of the host galaxy [25].…”