Searching for the electron/positron pair halo of the Blazar H1426+428 using XMM-Newton

Abstract

Electron/positron pair halo is a physical phenomenon in which the very high energy gamma rays emitted from Blazar interact with cosmic infrared background (CIB) so that produce the electron/positron pairs; the produced electron/positron pairs could up-scatter the cosmic microwave background (CMB) reproducing the gamma-rays, thus these form the cascade process of producing the electron/positron pairs appearing as an halo around the blazar. In case that the halo presents in the ambient strong magnetic field, the electron/positron pairs could emit X-ray light via synchrotron process providing another opportunity to detect the halo. In this work, we search for the X-ray emission from the halo of the Blazar H1426+428 using the observed X-ray data from XMM-Newton observatory. The X-ray spectra of the halo are carefully extracted from the annulus, source free regions around the Blazar to avoid the X-ray contaminations from the Blazar itself and the nearby point sources. These spectra were fitted using the physical model which takes into account the emissions from the unresolved cosmic X-ray and instrument backgrounds. The unresolved flux of ≍ 10–13 erg s–1 cm–2 have been detected in the regions, and we argue that, at least, some fraction of the flux might be the emission from the halo.