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Volume 85, Number 2, January 2009
Article Number 29001
Number of page(s) 6
Section Geophysics, Astronomy and Astrophysics
Published online 28 January 2009
EPL, 85 (2009) 29001
DOI: 10.1209/0295-5075/85/29001

Tachyonic $\chem{\gamma}$-ray cascades from BL Lacertae objects

R. Tomaschitz

Department of Physics, Hiroshima University - 1-3-1 Kagami-yama, Higashi-Hiroshima 739-8526, Japan

received 28 November 2008; accepted in final form 15 December 2008; published January 2009
published online 28 January 2009

Evidence for superluminal radiation from TeV blazars is pointed out. Spectral fits of the BL Lacertae objects W Comae, 1ES 2344+514, PG 1553+113, and 1ES 0806+524 are performed with tachyonic $\gamma $-ray cascades generated by the thermal electron plasma in the galactic nuclei. The transversal and longitudinal radiation components as well as the thermodynamic parameters of the ultra-relativistic electron populations are extracted from the spectral maps based on EGRET, VERITAS, MAGIC, and HESS flux data. An extended spectral plateau typical for tachyonic $\gamma $-ray spectra emerges in the MeV and low GeV range, terminating in exponential decay without a power law crossover. Thermal tachyonic cascade spectra are also predicted for Fermi blazars. By comparing to other TeV $\gamma $-ray sources such as Galactic supernova remnants and pulsar wind nebulae as well as active galactic nuclei, the curvature in the high-energy spectral slopes of BL Lacertae objects is shown to be intrinsic, i.e. uncorrelated with distance.

98.54.Cm - Active and peculiar galaxies and related systems (including BL Lacertae objects, blazars, Seyfert galaxies, Markarian galaxies, and active galactic nuclei).
52.27.Ny - Relativistic plasmas.
95.30.Gv - Radiation mechanisms; polarization.

© EPLA 2009