Astron. Astrophys. 332, 55-70 (1998)

The Galactic X-ray halo

J. Pietz ¹, J. Kerp ¹, P.M.W. Kalberla ¹, W.B. Burton ², Dap Hartmann ^{2, 3} and U. Mebold <sup>1

1</sup> Radioastronomisches Institut der Universität Bonn, Auf dem Hügel 71, D-53121 Bonn, Germany
² Sterrewacht Leiden, P.O. Box 9513, RA 2300 Leiden, The Netherlands
³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

Received 27 February 1997 / Accepted 8 December 1997

Abstract

We analyzed the intensity distribution of the keV and keV diffuse soft X-ray background by correlating the ROSAT all-sky survey with the Leiden/Dwingeloo H I  survey. We found that the keV and keV intensity distributions can be modelled by a contribution from an isothermal (k ) flattened X-ray halo superposed on the radiation from an extragalactic X-ray background. The exponential scale height of the X-ray halo is about 4.4 kpc and its radial scale length is about ; the X-ray halo luminosity, , is about .

Key words: Galaxy: halo Galaxy: kinematics and dynamics X-rays: ISM

Send offprint requests to: P.M.W. Kalberla

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Contents

• 1. Introduction
• 2. Data
  • 2.1. Soft X-ray data
  • 2.2. H I data
• 3. Spectral components of the XRB
• 4. The keV RASS data
  • 4.1. Residual contamination of the RASS data
  • 4.2. Dependence of the keV amplitudes on galactic longitude
• 5. Distribution of the thermal keV XRB
  • 5.1. Modeling the keV XRB
  • 5.2. A halo hydrostatic-equilibrium model
  • 5.3. Flattened-halo model versus spherical-halo model
  • 5.4. Comparison of the best-fit flattened-halo model with the observations
• 6. The keV X-ray background
  • 6.1. Modeling the keV sky
• 7. Summary
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: March 10, 1998
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