Astron. J., 155, 81-81 (2018/February-0)
Diffuse X-ray-emitting gas in major mergers.
SMITH B.J., CAMPBELL K., STRUCK C., SORIA R., SWARTZ D., MAGNO M., DUNN B. and GIROUX M.L.
Abstract (from CDS):
Using archived data from the Chandra X-ray telescope, we have extracted the diffuse X-ray emission from 49 equal-mass interacting/merging galaxy pairs in a merger sequence, from widely separated pairs to merger remnants. After the removal of contributions from unresolved point sources, we compared the diffuse thermal X-ray luminosity from hot gas (LX(gas)) with the global star formation rate (SFR). After correction for absorption within the target galaxy, we do not see a strong trend of LX(gas)/SFR with the SFR or merger stage for galaxies with SFR > 1 M☉ yr–1. For these galaxies, the median LX(gas)/SFR is 5.5 x 1039 ((erg s–1)/M☉ yr–1)), similar to that of normal spiral galaxies. These results suggest that stellar feedback in star-forming galaxies reaches an approximately steady-state condition, in which a relatively constant fraction of about 2% of the total energy output from supernovae and stellar winds is converted into X-ray flux. Three late-stage merger remnants with low SFRs and high K-band luminosities (LK) have enhanced LX(gas)/SFR; their UV/IR/optical colors suggest that they are post-starburst galaxies, perhaps in the process of becoming ellipticals. Systems with LK < 1010 L☉ have lower LX(gas)/SFR ratios than the other galaxies in our sample, perhaps due to lower gravitational fields or lower metallicities. We see no relation between LX(gas)/SFR and Seyfert activity in this sample, suggesting that feedback from active galactic nuclei is not a major contributor to the hot gas in our sample galaxies.
© 2018. The American Astronomical Society. All rights reserved.
galaxies: evolution - galaxies: ISM - galaxies: star formation - galaxies: interactions - X-rays: ISM
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<Available at CDS (J/AJ/155/81): table1.dat table2.dat table3.dat table4.dat table5.dat table6.dat>
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