Map of the Galaxy in the 6.7-keV emission line

Authors

  • M. Revnivtsev,

    Corresponding author
    1. Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany
    2. Space Research Institute (IKI), Profsoyuznaya 84/32, Moscow 117997, Russia
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  • S. Molkov,

    1. Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany
    2. Space Research Institute (IKI), Profsoyuznaya 84/32, Moscow 117997, Russia
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  • S. Sazonov

    1. Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany
    2. Space Research Institute (IKI), Profsoyuznaya 84/32, Moscow 117997, Russia
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E-mail: mikej@mpa-garching.mpg.de

ABSTRACT

We study the two-dimensional surface brightness distribution of the Galactic X-ray background emission outside the central degree around Sgr A* in the 6.7-keV line as measured by the Proportional Counter Array spectrometer of the Rossi X-ray Timing Explorer observatory. The use of the emission line instead of continuum (3–20 keV) radiation and application of time-variability filtering to the long data set allows us to strongly suppress the contamination of the Galactic ridge X-ray emission (GRXE) map by bright point-sources. The surface brightness in the 6.7-keV line demonstrates very good correspondence with the near-infrared surface brightness over the whole Galaxy, supporting the notion that the GRXE consists mostly of integrated emission from weak Galactic X-ray sources. We find compatible linear correlations between near-infrared and 6.7-keV surface brightness for the bulge and disc of the Galaxy. This indicates that the populations of weak X-ray sources making up the GRXE in the disc and in the bulge are not significantly different.

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