INTEGRAL observations of the cosmic X-ray background in the 5–100 keV range via occultation by the Earth

By E. Churazov, R. Sunyaev, M. Revnivtsev, S. Sazonov, S. Molkov, S. Grebenev, C. Winkler, A. Parmar, A. Bazzano, M. Falanga and 25 more. 2006

153 citations recorded by the source corpus.

Aims. We study the spectrum of the cosmic X-ray background (CXB) in energy range ∼5−100 keV. Methods. Early in 2006 the INTEGRAL observatory performed a series of four 30 ks observations with the Earth disk crossing the field of view of the instruments. The modulation of the aperture flux due to occultation of extragalactic objects by the Earth disk was used to obtain the spectrum of the Cosmic X-ray Background (CXB). Various sources of contamination were evaluated, including compact sources, Galactic Ridge emission, CXB reflection by the Earth atmosphere, cosmic ray induced emission by the Earth atmosphere and the Earth auroral emission. Results. The spectrum of the cosmic X-ray background in the energy band 5−100 keV is obtained. The shape of the spectrum is consistent with that obtained previously by the HEAO-1 observatory, while the normalization is ∼10% higher. This difference in normalization can (at least partly) be traced to the different assumptions on the absolute flux from the Crab Nebulae. The increase relative to the earlier adopted value of the absolute flux of the CXB near the energy of maximum luminosity (20−50 keV) has direct implications for the energy release of supermassive black holes in the Universe and their growth at the epoch of the CXB origin.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/663991825fc48211de305848f6ff4244bf1b5c91

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In Astronomy and Astrophysics

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In Nuclear and High Energy Physics

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Citations in the corpus

• Modeling and Reproducibility of Suzaku HXD PIN/GSO Background (2009, background): “The earth albedo is at most 10 % of the CXB flux below 50 keV (Imhof et al. 1976; Churazov et al. 2007; Frontera et al. 2007; Sazonov et al. 2007; Churazov et al. 2008), and the CXB flux is 5% of the PIN NXB and <0.5% of the GSO NXB.”
• TOWARD THE STANDARD POPULATION SYNTHESIS MODEL OF THE X-RAY BACKGROUND: EVOLUTION OF X-RAY LUMINOSITY AND ABSORPTION FUNCTIONS OF ACTIVE GALACTIC NUCLEI INCLUDING COMPTON-THICK POPULATIONS (2014, methodology): “The data points represent the measurements of the XRB observed with various missions includingHEAO1A4 in the 100–300 keV band (Gruber et al. 1999),Swift/BAT in the 14–195 keV band (Ajello et al. 2008), andINTEGRALin the 4–215 keV band (Churazov et al. 2007).”
• THE SPACE DENSITY OF COMPTON-THICK ACTIVE GALACTIC NUCLEUS AND THE X-RAY BACKGROUND (2009, methodology): “In Figure 4 we show the values of the normalization of the Compton reflection component and CT AGN number density that produce XRB intensities in the 20- 40 keV region consistent with the latest observed values from INTEGRAL (Churazov et al. 2007) and Swift (Ajello et al. 2008).”
• The PalermoSwift-BAT hard X-ray catalogue: II. Results after 39 months of sky survey (2009, background): “The main results of this survey and the relevant source catalogues are reported in several papers (e.g. Bird et al. 2004, 2006, 2007; Bassani et al. 2006; Krivonos et al. 2007, 2005; Sazonov et al. 2007; Churazov et al. 2007).”
• Cosmic X-Ray Background and Earth Albedo Spectra with Swift BAT (2008, methodology): “Its normalization has been derived during the measurement of the CXB intensity (Churazov et al. 2007).”