Large-scale Hot Structures

The origin of the eROSITA bubble is still debated. Some argue it originates from the past activity of Milky Way’s SMBH (Sgr A⋆), while others favor a stellar feedback origin. The confusion mainly arises from the relatively poor measurement of elemental abundances as well as the emission measure distribution as a function of temperature. In addition, DIXE can constrain the kinematics if the bubbles have a significant Doppler shift due to their motion.  DIXE observation can easily verify theoretical predictions. Another example is the Cygnus loop, which is a nearby supernova remnant (SNR) where charge exchange features and the “low-abundance problem”  were suggested for some local structures. A global high-resolution X-ray spectroscopic view of the entire SNR is still lacking.