Strong GeV emission accompanying TeV blazar H1426+428

¹ Department of Astronomy, Nanjing University, Nanjing 210093, PR China
² Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, PR China
³ National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China

Corresponding author: Y. Z. Fan, yzfan@pmo.ac.cn

Received: 8 September 2003
Accepted: 28 October 2003

Abstract

For High frequency BL Lac objects (HBLs) like H1426+428, a significant fraction of their TeV gamma-rays emitted are likely to be absorbed in interactions with the diffuse IR background, yielding e pairs. The resulting e pairs generate one hitherto undiscovered GeV emission by inverse Compton scattering with the cosmic microwave background photons (CMBPs). We study such emission by taking the 1998-2000 CAT data, the reanalyzed 1999 & 2000 HEGRA data and the corresponding intrinsic spectra proposed by Aharonian et al. ([CITE]). We numerically calculate the scattered photon spectra for different intergalactic magnetic field (IGMF) strengths. If the IGMF is about or weaker, there comes very strong GeV emission, whose flux is far above the detection sensitivity of the upcoming satellite GLAST! Considered its relatively high redshift (), the detected GeV emission in turn provides us a valuable chance to calibrate the poorly known spectral energy distribution of the intergalactic infrared background, or provides us some reliable constraints on the poorly known IGMF strength.