THE EFFECTS OF ACCRETION FLOW DYNAMICS ON THE BLACK HOLE SHADOW OF SAGITTARIUS A*
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Pu-2016-THE EFFECTS of ACCRETION FLOW DYNAMICS.pdf
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Author(s)
Pu, Hung-Yi
Asada, Keiichi
Akiyama, Kazunori
Date Issued
October 2016
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Pu, Hung-Yi; Akiyama, Kazunori and Asada, Keiichi. “THE EFFECTS OF ACCRETION FLOW DYNAMICS ON THE BLACK HOLE SHADOW OF SAGITTARIUS A*.” The Astrophysical Journal 831, no. 1 (October 2016): 4 © 2016 The American Astronomical Society
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Final published version
Abstract
A radiatively inefficient accretion flow (RIAF), which is commonly characterized by its sub-Keplerian nature, is a favored accretion model for the supermassive black hole at the Galactic center, Sagittarius A*. To investigate the observable features of an RIAF, we compare the modeled shadow images, visibilities, and spectra of three flow models with dynamics characterized by (i) a Keplerian shell that is rigidly rotating outside the innermost stable circular orbit (ISCO) and infalling with a constant angular momentum inside ISCO, (ii) a sub-Keplerian motion, and (iii) a free-falling motion with zero angular momentum at infinity. At near-millimeter wavelengths, the emission is dominated by the flow within several Schwarzschild radii. The energy shift due to these flow dynamics becomes important and distinguishable, suggesting that the flow dynamics are an important model parameter for interpreting the millimeter/sub-millimeter very long baseline interferometric observations with the forthcoming, fully assembled Event Horizon Telescope (EHT). As an example, we demonstrate that structural variations of Sagittarius A* on event horizon-scales detected in previous EHT observations can be explained by the non-stationary dynamics of an RIAF.
MIT Department
Haystack Observatory
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DOI of Published Version
http://dx.doi.org/10.3847/0004-637X/831/1/4
