Bipolar-Hyper-Shell Galactic Center Starburst Model: Further Evidence from ROSAT Data and New Radio and X-ray Simulations

Yoshiaki SOFUE


(1) Institute of Astronomy, University of Tokyo, Mitaka, Tokyo 181-8588

Paper: ApJ, in press


Abstract:

Using the all-sky ROSAT soft X-ray and 408-MHz radio continuum data, we show that the North Polar Spur and its western and southern counter-spurs draw a giant dumbbell-shape necked at the galactic plane. We interpret these features as due to a shock front originating from a starburst 15 million years ago with a total energy of the order of 1056 ergs or 105 type II supernovae. We simulate all-sky distributions of radio continuum and soft X-ray intensities based on the bipolar-hyper-shell galactic center starburst model. The simulations can well reproduce the radio NPS and related spurs, as well as radio spurs in the tangential directions of spiral arms. Simulated X-ray maps in 0.25, 0.75 and 1.5 keV bands reproduce the ROSAT X-ray NPS, its western and southern counter-spurs, and the absorption layer along the galactic plane. We propose to use the ROSAT all-sky maps to probe the physics of gas in the halo-intergalactic interface, and to directly date and measure the energy of a recent Galactic Center starburst.


Preprints available from the authors at sofue@mtk.ioa.s.u-tokyo.ac.jp , or the raw TeX (no figures) if you click here.

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