Photoelectric magnitudes and polarization data for possible BL Lacertae objects

Abstract

view Abstract Citations (113) References (47) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Photoelectric magnitudes and polarization data for possible BL Lacertae objects. Kinman, T. D. Abstract Photoelectric UBV magnitudes and polarization data are given for a sample of radio sources with continuous or weak-lined optical spectra which are possible BL Lacertae objects. The majority show optical variability and significant variable polarization. If no extended optical component is visible, the mean colors are consistent with these objects having power-law spectra F(v) - a, where +0.7 < a < +2.4; the most negative indices are likely to be spurious because of the effect of an unseen extended component. Objects with and without visible extended components are separated on a plot of spectral index against apparent magnitude. It is shown to be difficult to adopt a useful sharp definition of a BL Lacertae object, and the similarity of this general class to the variable emission-line quasars is stressed. The separation of BL Lacertae objects from field stars on the (U - V)/(B - R) two-color diagram is suggested as a means of identification. Subject headings: BL Lacertae objects - polarization - quasars - radio sources: variable Publication: The Astrophysical Journal Pub Date: April 1976 DOI: 10.1086/154244 Bibcode: 1976ApJ...205....1K Keywords: Polarization Characteristics; Quasars; Radio Sources (Astronomy); Ubv Spectra; Astronomical Catalogs; Electrophotometry; Emission Spectra; Infrared Astronomy; Tables (Data); Astrophysics full text sources ADS | data products SIMBAD (33) NED (6)