Resolving the Bondi Accretion Flow toward the Supermassive Black Hole of NGC 3115 with Chandra

Ka-Wah Wong, Minnesota State University Mankato
Jimmy A. Irwin, University of Alabama - Tuscaloosa
Evan T. Million, University of Alabama - Tuscaloosa
Mihoko Yukita, Johns Hopkins University
William G. Mathews, University of California, Santa Cruz
Joel N. Bregman, University of Michigan - Ann Arbor


Gas undergoing Bondi accretion on to a supermassive black hole (SMBH) becomes hotter toward smaller radii. We searched for this signature with a Chandra observation of the hot gas in NGC 3115, which optical observation show has a very massive SMBH. Our observations show that the gas temperature rises toward the galaxy center as expected in all accretion models in which the black hole is gravitationally capturing the ambient gas. The data support that the Bondi radius is at least about 4-5 arcsec (188-235 pc), suggesting a supermassive blackhole of two billion solar masses that is consistent with the upper end of the optical results. The density profile within the Bondi radius has a power law index of 1.03, and we will discuss the interpretations of the results.