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Title: THE GALACTIC CENTER WEATHER FORECAST

Abstract

In accretion-based models for Sgr A*, the X-ray, infrared, and millimeter emission arise in a hot, geometrically thick accretion flow close to the black hole. The spectrum and size of the source depend on the black hole mass accretion rate M-dot . Since Gillessen et al. have recently discovered a cloud moving toward Sgr A* that will arrive in summer 2013, M-dot may increase from its present value M-dot{sub 0}. We therefore reconsider the 'best-bet' accretion model of Moscibrodzka et al., which is based on a general relativistic MHD flow model and fully relativistic radiative transfer, for a range of M-dot . We find that for modest increases in M-dot the characteristic ring of emission due to the photon orbit becomes brighter, more extended, and easier to detect by the planned Event Horizon Telescope submillimeter Very Long Baseline Interferometry experiment. If M-dot {approx}>8 M-dot{sub 0}, this 'silhouette' of the black hole will be hidden beneath the synchrotron photosphere at 230 GHz, and for M-dot {approx}>16 M-dot{sub 0} the silhouette is hidden at 345 GHz. We also find that for M-dot > 2 M-dot{sub 0} the near-horizon accretion flow becomes a persistent X-ray and mid-infrared source, and in the near-infrared Sgrmore » A* will acquire a persistent component that is brighter than currently observed flares.« less

Authors:
 [1]; ;  [2];  [3]
  1. Department of Physics and Astronomy, University of Nevada, 4505 South Maryland Parkway, Las Vegas, NV 89154 (United States)
  2. Astronomy Department, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States)
  3. Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08544 (United States)
Publication Date:
OSTI Identifier:
22047771
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 752; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; BLACK HOLES; FLOW MODELS; GALAXIES; GHZ RANGE; INFRARED RADIATION; INTERFEROMETRY; MAGNETOHYDRODYNAMICS; MASS; ORBITS; PHOTON EMISSION; PHOTOSPHERE; RADIANT HEAT TRANSFER; RELATIVISTIC RANGE; STAR ACCRETION; TELESCOPES; X RADIATION

Citation Formats

Moscibrodzka, M., Shiokawa, H., Gammie, C. F., and Dolence, J. C., E-mail: monikam@physics.unlv.edu. THE GALACTIC CENTER WEATHER FORECAST. United States: N. p., 2012. Web. doi:10.1088/2041-8205/752/1/L1.
Moscibrodzka, M., Shiokawa, H., Gammie, C. F., & Dolence, J. C., E-mail: monikam@physics.unlv.edu. THE GALACTIC CENTER WEATHER FORECAST. United States. doi:10.1088/2041-8205/752/1/L1.
Moscibrodzka, M., Shiokawa, H., Gammie, C. F., and Dolence, J. C., E-mail: monikam@physics.unlv.edu. Sun . "THE GALACTIC CENTER WEATHER FORECAST". United States. doi:10.1088/2041-8205/752/1/L1.
@article{osti_22047771,
title = {THE GALACTIC CENTER WEATHER FORECAST},
author = {Moscibrodzka, M. and Shiokawa, H. and Gammie, C. F. and Dolence, J. C., E-mail: monikam@physics.unlv.edu},
abstractNote = {In accretion-based models for Sgr A*, the X-ray, infrared, and millimeter emission arise in a hot, geometrically thick accretion flow close to the black hole. The spectrum and size of the source depend on the black hole mass accretion rate M-dot . Since Gillessen et al. have recently discovered a cloud moving toward Sgr A* that will arrive in summer 2013, M-dot may increase from its present value M-dot{sub 0}. We therefore reconsider the 'best-bet' accretion model of Moscibrodzka et al., which is based on a general relativistic MHD flow model and fully relativistic radiative transfer, for a range of M-dot . We find that for modest increases in M-dot the characteristic ring of emission due to the photon orbit becomes brighter, more extended, and easier to detect by the planned Event Horizon Telescope submillimeter Very Long Baseline Interferometry experiment. If M-dot {approx}>8 M-dot{sub 0}, this 'silhouette' of the black hole will be hidden beneath the synchrotron photosphere at 230 GHz, and for M-dot {approx}>16 M-dot{sub 0} the silhouette is hidden at 345 GHz. We also find that for M-dot > 2 M-dot{sub 0} the near-horizon accretion flow becomes a persistent X-ray and mid-infrared source, and in the near-infrared Sgr A* will acquire a persistent component that is brighter than currently observed flares.},
doi = {10.1088/2041-8205/752/1/L1},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 752,
place = {United States},
year = {2012},
month = {6}
}