Abstract The interstellar medium of galaxies, with temperatures reaching several million degrees, provides a pivotal perspective for understanding the physical and chemical properties of star formation, galactic evolution, and their associated feedback mechanisms. We use archival data from Chandra observations to extract the diffuse X-ray emission from 23 nearby star-forming galaxies and study its correlation with star formation activity in the central region of these galaxies. The surface brightness profile of each galaxy presents a sharp decrease in the central region of ∼0.3−2 kpc and then varies slowly outside this range. Compared to the global relation between the diffuse thermal X-ray luminosity from hot gas ( L 0.5 − 2 keV gas ) and the star formation rate (SFR), we found a superlinear relation of log ( L gas 0 . 5 − 2 keV / erg s − 1 ) = 1.34 log ( SFR / M ⊙ yr − 1 ) + 40.15 for the center of these sample galaxies. This result suggests that more intense stellar feedback is associated with stronger star formation activity in the central region of star-forming galaxies, where more energy output from supernovae and stellar winds is converted into X-ray flux. Furthermore, the slope of the L 0.5 − 2 keV gas –SFR relation anticorrelates with spatial scale in the galactic central region. This indicates that the characteristics of central hot gas emission are gradually averaged over larger areas. The diffuse X-ray luminosity also shows a good correlation with molecular gas, stellar mass, and midplane pressure traced by the baryonic mass, although these relations show relatively large scatter.
Zhang et al. (Tue,) studied this question.