2025/06/21 by Zhang, Chunyi, Wang, Junfeng · 1 citation
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2506.17663
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 \thicksim0.3-2 kpc and then varies slowly outside this range. Compared to the global relation between the diffuse thermal X-ray luminosity from hot gas (L\rm 0.5 - 2 keV\rm gas) and the star formation rate (SFR), we found a super-linear relation of \rm log(L\rm 0.5-2 keV\rm gas /\rm erg s-1)=1.34 \rm log(\rm SFR/M\rm \odot \rm 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 (SNe) and stellar winds is converted into X-ray flux. Furthermore, the slope of the L\rm 0.5 - 2 keV\rm 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 mid-plane pressure traced by the baryonic mass, although these relations show relatively large scatter.