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BL Lac Objects and Their Associated Galaxies

Published online by Cambridge University Press:  14 August 2015

Donna Weistrop*
Affiliation:
Laboratory for Astronomy and Solar Physics, Goddard Space Flight Center Greenbelt, Maryland

Abstract

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CCD photometry of five BL Lac objects indicates that at least three, and possibly four, are located at the centers of giant elliptical galaxies. The redshift for one of these objects, 1218+304, is estimated. A lower limit is placed on the redshift of 1219+28, for which no associated galaxy has been detected. Separation of the galaxy emission from the total observed flux makes possible comparison of the optical — far red flux from the point source alone with radio and X-ray data. This comparison suggests the emission from 1727+50 and 1218+304 can be interpreted as due to direct synchrotron emission. Observations of a small group of galaxies associated with the BL Lac object 1400+162 are also discussed.

Type
Research Article
Copyright
Copyright © Reidel 1982 

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