Multifrequency observations of blazars. IV - The variability of the radio to ultraviolet continuum

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view Abstract Citations (82) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Multifrequency Observations of Blazars. IV. The Variability of the Radio to Ultraviolet Continuum Brown, L. M. J. ; Robson, E. I. ; Gear, W. K. ; Smith, M. G. Abstract We present the results of analysis of the variability properties of the high-frequency radio (centimeter) to ultraviolet continua of a sample of nine blazars. Three sources, 0851+202 (OJ 287), 1641+399 (3C 345) and 2223-052 (3C 446), have sufficiently complete spectral and temporal coverage to enable detailed comparisons to be made between the light curves obtained at the various wavebands. The infrared and optical variations of these sources are well correlated. In OJ 287 there is also a significant correlation between the centimeter variations and those at higher frequencies. In 3C 446, however, the centimeter variations appear to be uncorrelated with those at higher frequencies. A strong correlation is observed between the near-infrared flux levels and the near-infrared spectral slopes of the BL Lac objects, in the sense that the spectra are steeper when the sources are fainter. A similar correlation is observed to hold in optically violent variable (OVV) quasars during large-amplitude flare events; in general, however, the spectra of the OVV quasars exhibit no significant correlation between flux level and spectral slope. We deduce that an additional nonvariable 1-5 micron component may be present in the near-infrared spectra of OVV quasars. We also note that the supposed BL Lac object, 1308+328, shows properties intermediate between the two classes and clearly merits further study. Publication: The Astrophysical Journal Pub Date: May 1989 DOI: 10.1086/167381 Bibcode: 1989ApJ...340..150B Keywords: Astronomical Spectroscopy; Continuous Spectra; Extragalactic Radio Sources; Quasars; Bl Lacertae Objects; Light Curve; Radio Spectra; Ultraviolet Spectra; Astrophysics; BL LACERTAE OBJECTS; QUASARS; RADIATION MECHANISMS; RADIO SOURCES: VARIABLE full text sources ADS | data products SIMBAD (10) NED (9) Related Materials (3) Part 1: 1985ApJ...291..511G Part 2: 1986ApJ...304..295G Part 3: 1989ApJ...340..129B