The XMM-Newton view of the central degrees of the Milky Way

Abstract

The deepest XMM-Newton mosaic map of the central 1.5 ° of the Galaxy is presented, including a total of about 1.5 Ms of EPIC-pn cleaned exposures in the central 15 arcsec and about 200 ks outside. This compendium presents broad-band X-ray continuum maps, soft X-ray intensity maps, a decomposition into spectral components and a comparison of the X-ray maps with emission at other wavelengths. Newly discovered extended features, such as supernova remnants (SNRs), superbubbles and X-ray filaments are reported. We provide an atlas of extended features within ±1° of Sgr A<SUP>⋆</SUP>. We discover the presence of a coherent X-ray-emitting region peaking around G0.1-0.1 and surrounded by the ring of cold, mid-IR-emitting material known from previous work as the `Radio Arc Bubble' and with the addition of the X-ray data now appears to be a candidate superbubble. Sgr A's bipolar lobes show sharp edges, suggesting that they could be the remnant, collimated by the circumnuclear disc, of an SN explosion that created the recently discovered magnetar, SGR J1745-2900. Soft X-ray features, most probably from SNRs, are observed to fill holes in the dust distribution, and to indicate a direct interaction between SN explosions and Galactic centre (GC) molecular clouds. We also discover warm plasma at high Galactic latitude, showing a sharp edge to its distribution that correlates with the location of known radio/mid-IR features such as the `GC Lobe'. These features might be associated with an inhomogeneous hot `atmosphere' over the GC, perhaps fed by continuous or episodic outflows of mass and energy from the GC region.