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Session 66 - Radio - Loud AGN & Extragalactic Jets.
Oral session, Thursday, January 08
Results of two studies involving outflows from radio loud active galactic nuclei (AGN) are presented. The first study examines relativistic outflows from the cores of different classes of AGN, and estimates of bulk Lorentz factors and viewing angles. The second study deals with powerful extended radio galaxies, the relation between lifetime and luminosity in directed kinetic energy, and the use of these sources for cosmology.
Relativistic outflows from compact radio sources are examined. Two sets of Doppler factor estimates, one using the equipartition method and the other using the inverse Compton method, for 100 radio cores are discussed. Intrinsic brightness temperatures based on these Doppler factors are examined along with their relevance to the ``inverse Compton catastrophe''. Intrinsic luminosities are computed and discussed. Outflow angles and bulk Lorentz factors are computed for 43 out of the 100 sources on the basis of previously compiled proper motions. These estimates of outflow angles and bulk Lorentz factors and their agreement with orientation unified models of AGN are discussed.
Powerful extended radio galaxies are examined, and the relation between the active lifetime and the luminosity in directed kinetic energy in these sources is investigated by comparing the redshift evolution of characteristic source sizes to the redshift evolution of the average lobe-lobe size. It is found that the data are accurately described by a model in which the active lifetime of the source, t_*, is written as a power-law in the beam power, L_j. The exponent of the power law is estimated to be \beta \simeq 2.1 \pm 0.6, where t_* \propto L_j^-\beta/3, excluding \beta=0, the vaue expected for an Eddington-limited system. The same comparison of characteristic source sizes to lobe-lobe sizes is used to constrain cosmological parameters. The data indicate a low value of Ømega_o, about 2\sigma away from a flat, matter-dominated universe.
Program listing for Thursday