Intensity of the cosmic X-ray backgound from HEAO1/A2 experiment

¹ Max-Planck-Institute für Astrophysik, Karl-Schwarzschild-Str. 1, 85740 Garching bei München, Germany e-mail: mikej@mpa-garching.mpg.de
² Space Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32, 117810 Moscow, Russia
³ Laboratory for High Energy Astrophysics, Code 662, Goddard Space Flight Center, Greenbelt, MD 20771, USA

Received: 13 December 2004
Accepted: 4 August 2005

Abstract

We reanalyze data of HEAO1/A2 – the Cosmic X-ray Experiment – in order to repeat the measurements of the cosmic X-ray background (CXB) intensity and accurately compare this value with other measurements of the CXB. We used the data of MED, HED1, and HED3 detectors in scan mode, which allowed us to measure effective solid angles and effective areas of detectors self consistently, in the same mode as the CXB intensity was measured. We found that the average value of the CXB intensity is  erg s^-1 cm^-2 deg^-2 in the energy band 2-10 keV, or  phot s^-1 cm^-2 at 1 keV assuming the power law spectral shape with photon index in this energy band. We compare the obtained measurements with those obtained by different instruments over the past few decades.