CXOU J073700.0+653506 , the SIMBAD biblio

Archival Chandra observations are used to study the X-ray emission associated with star formation in the central region of the nearby SAB(s)cd galaxy NGC 2403. The distribution of X-ray emission is compared to the morphology visible at other wavelengths using complementary Spitzer, Galaxy Evolution Explorer, and ground-based Hα imagery. In general, the brightest extended X-ray emission is associated with H II regions and to other star-forming structures but is more pervasive, existing also in regions devoid of strong Hα and UV emission. This X-ray emission has the spectral properties of diffuse hot gas (kT ∼ 0.2 keV) whose likely origin is in gas shock heated by stellar winds and supernovae with ≲20% coming from faint unresolved X-ray point sources. This hot gas may be slowly cooling extra-planar remnants of past outflow events, or a disk component that either lingers after local star formation activity has ended or that has vented from active star-forming regions into a porous interstellar medium.