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Session 103 - Quasars & Blazars.
Display session, Saturday, January 10
The NRAO VLA Sky Survey (NVSS) has been used to examine the immediate vicinity of a large sample of quasars, taken from the catalog of Veron-Cetty and Veron. The radio source counts differ significantly from the NVSS background only within a 1-arcminute radius of the quasar positions. Within this radius, a strong statistical excess of radio sources not coincident with the optical quasars is detected. Some of these excess sources are shown to be the double lobes of apparently normal radio-loud objects. The majority, however, are relatively weak single sources which lie a few tens of arcseconds from the associated quasar. The reality of the association is supported by an inverse correlation between the flux density of the associated sources and the redshift of the associated quasar. The radio sources could be due to active nuclei in galaxies belonging to clusters in which the quasars reside, yielding constraints on AGN rates and radio luminosity functions, as well as cluster properties at high redshift. Alternatively, the sources may represent a hitherto unknown manifestation of quasar activity, presumably related to radio loudness despite the predominance of radio-quiet quasars in the associations.
Program listing for Saturday