Vol 18, No 10 (2018) / Lin

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Spectral energy distributions for TeV blazars

Chao Lin, Jun-Hui Fan


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, \(\log ν_{\rm p}^{\rm s}\), and the inverse-Compton peak frequency, \(\log ν_{\rm p}^{\rm IC}\), and between the synchrotron peak luminosity, \(\log ν_{\rm p}^{\rm s}L^{\rm s}_{v_p}\), and the inverse-Compton peak luminosity, \(\log ν_{\rm p}^{\rm IC} L^{\rm IC}_{ν_p}\) . (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 \(\log ν_{\rm p}^{\rm IC}\) and γ-ray spectral index, αγ, for the TeV blazars: \(\log ν_{\rm p}^{\rm IC} = −(4.59 \pm 0.30)α_γ + (32.67 \pm 0.59)\), which is consistent with previous work. (4) An “L-shape” relation is found between \(\log ν_{\rm p}^{\rm s}\) and \(α_X\) for both TeV blazars and Fermi blazars. A significant correlation between \(\log ν_{\rm p}^{\rm s}\) and X-ray photon index (\(α_X\)) is found for the TeV blazars with high synchrotron peak frequency: \(\log ν_{\rm p}^{\rm s} = −(3.20 \pm 0.34)α_X + (24.33 \pm 0.79)\), while the correlation is positive for low synchrotron peaked TeV sources. (5) In the \(α_X - α_γ\)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.


galaxies: active — BL Lacertae objects: general — quasars: general — galaxies: jets

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DOI: https://doi.org/10.1088/1674–4527/18/10/120


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