0. 35-3. 5 micron photometry of blazars

• Published in: Publications of the Astronomical Society of the Pacific Vol. 103
• Main Authors: Sitko, M.L., Sitko, A.K.
• Format: Journal Article
• Language: English
• Published: United States 01-02-1991
• Subjects: 640102 - Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources; BREMSSTRAHLUNG; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CORRELATIONS; COSMIC RAY SOURCES; COSMIC X-RAY SOURCES; ELECTROMAGNETIC RADIATION; GALAXY NUCLEI; INFRARED RADIATION; LUMINOSITY; MATHEMATICAL MODELS; NEAR INFRARED RADIATION; OPTICAL PROPERTIES; PHOTOMETRY; PHYSICAL PROPERTIES; RADIATIONS; RED SHIFT; SYNCHROTRON RADIATION; VISIBLE RADIATION
• ISSN: 0004-6280; 1538-3873
• DOI: 10.1086/132804

Thirty-one blazars were observed photometrically in the near-infrared, with additional observations in the optical for many of them. A few of them exhibit spectral behavior indicative of multiple emission components or emission processes. Six objects were also analyzed for any possible correlation between spectral steepness and luminosity. In one object, 0735 + 178, the spectral index alpha is correlated with the flux level with 99.9 pct confidence. Two other objects, 0846 + 513 and 0851 + 202, showed similar correlations at the 98 and 90 pct confidence levels, respectively. In all three cases the spectrum became flatter at higher flux levels. the data are consistent with expectations of models of inhomogeneous synchrotron models. In some cases, the self-Compton component may contribute significantly to the optical flux. 27 refs.