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Title: The megasecond Chandra X-ray visionary project observation of NGC 3115: Witnessing the flow of hot gas within the Bondi radius

Observational confirmation of hot accretion model predictions has been hindered by the challenge to resolve spatially the Bondi radii of black holes with X-ray telescopes. Here, we use the Megasecond Chandra X-ray Visionary Project observation of the NGC 3115 supermassive black hole to place the first direct observational constraints on the spatially and spectroscopically resolved structures of the X-ray emitting gas inside the Bondi radius of a black hole. We measured temperature and density profiles of the hot gas from a fraction out to tens of the Bondi radius (R{sub B} = 2.''4-4.''8 = 112-224 pc). The projected temperature jumps significantly from ∼0.3 keV beyond 5'' to ∼0.7 keV within ∼4''-5'', but then abruptly drops back to ∼0.3 keV within ∼3''. This is contrary to the expectation that the temperature should rise toward the center for a radiatively inefficient accretion flow. A hotter thermal component of ∼1 keV inside 3'' (∼150 pc) is revealed using a two-component thermal model, with the cooler ∼0.3 keV thermal component dominating the spectra. We argue that the softer emission comes from diffuse gas physically located within ∼150 pc of the black hole. The density profile is broadly consistent with ρ∝r {sup –1} within themore » Bondi radius for either the single temperature or the two-temperature model. The X-ray data alone with physical reasoning argue against the absence of a black hole, supporting that we are witnessing the onset of the gravitational influence of the supermassive black hole.« less
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States)
  2. Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)
  3. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States)
Publication Date:
OSTI Identifier:
22348378
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; DENSITY; EMISSION; FORECASTING; GALAXY NUCLEI; HEAT EXCHANGERS; KEV RANGE; LIMITING VALUES; SPECTRA; TELESCOPES; X RADIATION; X-RAY GALAXIES