Skip to main content
The role of galactic cold gas in low-level supermassive black hole activity (2016)
  • Erik D. Alfvin, Macalester College
  • Brendan P. Miller
  • M. P. Haynes
  • E. Gallo
  • Riccardo Giovanelli
  • Rebecca A. Koopmann
  • John M Cannon
  • Edmund Hodges-Kluck
"The nature of the relationship between low-level supermassive black hole (SMBH) activity and galactic cold gas, if any, is currently unclear. Here, we test whether central black holes may feed at higher rates in gas-rich galaxies, probing SMBH activity well below the active regime down to Eddington ratios of ~1e-7. We use a combination of radio data from the ALFALFA survey and from the literature, along with archival X-ray flux measurements from the Chandra X-ray observatory, to investigate this potential relationship. We construct a sample of 129 late-type galaxies, with MB<-18 out to 50 Mpc, that have both HI masses and sensitive X-ray coverage. Of these, 75 host a nuclear X-ray source, a 58% detection fraction. There is a highly significant correlation between nuclear X-ray luminosity LX and galaxy stellar mass Mstar with a slope of 1.7+/-0.3, and a tentative correlation (significant at the 2.8 sigma level) between LX and HI gas mass MHI. However, a joint fit to LX as a function of both Mstar and MHI finds no significant dependence on MHI (slope 0.1+/00.3), and similarly the residuals of LX-LX(Mstar) show no trend with MHI; the apparent correlation between LX and MHI seems to be entirely driven by Mstar. We demonstrate quantitatively that these results are robust against X-ray binary contamination. We conclude that the galaxy-wide cold gas content in these spirals does not strongly correlate with their low-level supermassive black hole activity, and suggest fueling is a localized process." [Abstract from]
Publication Date
June 13, 2016
Citation Information
Erik D. Alfvin, Brendan P. Miller, M. P. Haynes, E. Gallo, et al.. "The role of galactic cold gas in low-level supermassive black hole activity" (2016)
Available at: