Multi-Frequency Study of Spectral Indices of BL Lacertae Objects and Flat Spectrum Radio Quasars

Abstract

We present statistical analyses of a large homogenous data sample of Fermi-detected blazars thoroughly studied in order to reassess the relationship between flat-spectrum radio quasars (FSRQs) and subclasses of BL Lacertae objects (BL Lacs) blazar populations. We discovered from the average values of gamma-ray and X-ray spectral indices that the sequence of distribution is indicative of the blazar orientation scheme. Analyses of FSRQs and BL Lacs data show difference in the shape of gamma-ray and X-ray indices: significant anti-correlation (r~ greater than - 0.79) exists between gamma-ray and X-ray spectral indices. The spectral energy distributions of the blazar subclasses show that FSRQs and BL Lacs have similar spectral properties which can be unified through an evolutionary sequence. Nevertheless, there is a significant difference between the shapes of X-ray and gamma-ray spectra of blazars suggesting that different mechanisms are responsible for spectral variations in the two energy bands. All these results suggest that there is a form of a unified scheme for all blazars.

18 pages, 11 figures, 2 Tables. Accepted for Publication in New Astronomy

References in corpus (8)

• Bright AGN Source List from the First Three Months of the Fermi Large Area Telescope All-Sky Survey
• The Blazar Sequence: Validity and Predictions
• Extremely violent optical microvariability in blazars: fact or fiction?
• Discerning the $\gamma$-ray emitting region in the flat spectrum radio quasars
• Evaluating the optical classification of Fermi BCUs using machine learning
• The sequence of Compton dominance in blazars based on data from WISE and Fermi/LAT
• What determines the observational differences of blazars?
• Spectral trends in the Very High Energy blazar sample due to EBL absorption

Cited by in corpus (1)

• On the Evolution of Seyfert galaxies, BL Lacertae objects and Flat-spectrum radio quasars