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Diffuse Thermal Emission from Very Hot Gas in Starburst Galaxies: Spectral Results

M. Cappi·M. Persic·S. Mariani·L. Bassani·L. Danese·A. J. Dean·G. Di Cocco·A. Franceschini·L. K. Hunt·F. Matteucci·E. Palazzi·G. G. C. Palumbo·Y. Rephaeli·P. Salucci·A. Spizzichino
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Abstract

New BeppoSAX observations of the nearby archetypical starburst galaxies (SBGs) NGC253 and M82 are presented. The main observational result is the unambiguous evidence that the hard (2-10 keV) component is (mostly) produced in both galaxies by thermal emission from a metal-poor (~ 0.1-0.3 solar), hot (kT \~ 6- 9 keV) and extended (see companion paper: Cappi et al. 1998) plasma. Possible origins of this newly discovered component are briefly discussed. A remarkable similarity with the (Milky Way) Galactic Ridge's X-ray emission suggests, nevertheless, a common physical mechanism.

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M. Cappi, M. Persic, S. Mariani, L. Bassani, L. Danese, A. J. Dean, G. Di Cocco, A. Franceschini, L. K. Hunt, F. Matteucci, E. Palazzi, G. G. C. Palumbo, Y. Rephaeli, P. Salucci, A. Spizzichino. 1998-09-25. Diffuse Thermal Emission from Very Hot Gas in Starburst Galaxies: Spectral Results. https://arxiv.org/abs/astro-ph/9809325

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