Unresolved emission and ionized gas in the bulge of M31
Abstract
We study origin of unresolved X-ray emission from the bulge of M31 based on archival Chandra and XMM-Newton observations. We demonstrate that three different components are present: (i) Broad-band emission from large number of faint sources - mainly accreting white dwarfs and active binaries, associated with the old stellar population, similar to the Galactic Ridge X-ray emission of the Milky Way. (ii) Soft emission from ionized gas with temperature of about ∼ 300 keV and mass of ∼ 4 · 106 M . The gas distribution is significantly elongated in the minor axis direction suggesting that it may be outflowing in the direction perpendicular to the galactic disk. The shadows cast on the gas by spiral arms and the 10-kpc star-forming ring confirm large off-plane extent of the gas. (iii) Hard unresolved emission from spiral arms, most likely associated with protostars and young stellar objects located in the star-forming regions. Its luminosity corresponds to about ∼ 1/3 of the HMXBs contribution, determined earlier from Chandra observations of other nearby galaxies.
- Publication:
-
37th COSPAR Scientific Assembly
- Pub Date:
- 2008
- Bibcode:
- 2008cosp...37.1016G