Spectral energy distributions for TeV blazars

Abstract

In this work, we collected a sample of 69 TeV blazars from TeVCat, obtained their multi-wavelength observations, and fitted their spectral energy distributions by using a second degree polynomial function. The structure parameters of synchrotron bumps for 68 blazars and those of inverse-Compton bumps for 56 blazars were derived. Then, we conducted statistical analysis on the parameters (curvature, peak frequency, peak luminosity, bolometric luminosity and X/γ-ray spectral indexes). From our analysis and discussions, we can conclude the following: (1) There is a clear positive correlation between the synchrotron peak frequency, , and the inverse-Compton peak frequency, , and between the synchrotron peak luminosity, , and the inverse-Compton peak luminosity, . (2) The correlation between the peak frequency and the curvature of synchrotron bump is clearly different from that of the inverse-Compton bump, which further indicates that there are different emission mechanisms between them. (3) There is a correlation between and γ-ray spectral index, αγ, for the TeV blazars: , which is consistent with previous work. (4) An “L-shape” relation is found between and αX for both TeV blazars and Fermi blazars. A significant correlation between and X-ray photon index (αX) is found for the TeV blazars with high synchrotron peak frequency: , while the correlation is positive for low synchrotron peaked TeV sources. (5) In the αX − αγ diagram, there is also an “L-shape.” The anti-correlation is consistent with results available in the literature, and we also find a positive correlation between them. (6) Inverse-Compton dominant sources have luminous bolometric luminosities.