Chandra large-scale mapping of the Galactic Centre: probing high-energy structures around the central molecular zone

Recent observations have revealed interstellar features that apparently connect energetic activity in the central region of our Galaxy to its halo. The nature of these features, however, remains largely uncertain. We present a Chandra mapping of the central 2 degrees x 4 degrees field of the Galaxy, revealing a complex of X-ray-emitting threads plus plume-like structures emerging from the Galactic Centre (GC). This mapping shows that the northern plume or fountain is offset from a well-known radio lobe (or the GCL), which however may represent a foreground HII region, and that the southern plume is well wrapped by a corresponding radio lobe recently discovered by MeerKAT. In particular, we find that a distinct X-ray thread, G0.17-0.41, is embedded well within a non-thermal radio filament, which is locally inflated. This thread with a width of similar to 1.6 arcsec (FWHM) is similar to 2.6 arcmin or 6 pc long at the distance of the GC and has a spectrum that can be characterized by a power law or an optically-thin thermal plasma with temperature greater than or similar to 3 keV. The X-ray-emitting material is likely confined within a strand of magnetic field with its strength greater than or similar to 1 mG, not unusual in such radio filaments. These morphological and spectral properties of the radio/X-ray association suggest that magnetic field re-connection is the energy source. Such re-connection events are probably common when flux tubes of antiparallel magnetic fields collide and/or become twisted in and around the diffuse X-ray plumes, representing blowout superbubbles driven by young massive stellar clusters in the GC. The understanding of the process, theoretically predicted in analog to solar flares, can have strong implications for the study of interstellar hot plasma heating, cosmic ray acceleration and turbulence.

Automated summary

Recent observations have shown interstellar features that connect energetic activity in the central region of our Galaxy to its halo, although the nature of these features remains uncertain. Chandra mapping has revealed a complex of X-ray-emitting threads and plume-like structures coming from the Galactic Center, indicating that magnetic field re-connection is likely the energy source. Studying the morphological and spectral properties of the radio/X-ray association may provide insights into processes such as interstellar plasma heating, cosmic ray acceleration, and turbulence.