STATISTICS OF X-RAY FLARES OF SAGITTARIUS A*: EVIDENCE FOR SOLAR-LIKE SELF-ORGANIZED CRITICALITY PHENOMENA
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Li-2015-STATISTICS OF X-RAY.pdf
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Author(s)
Li, Ya-Ping
Yuan, Feng
Yuan, Qiang
Wang, Q. Daniel
Chen, P. F.
Zhang, Shuo
Dexter, Jason
Neilsen, Joseph M. G.
Fang, Taotao, 1970-
Date Issued
August 2015
Journal
The Astrophysical Journal
Publisher
IOP Publishing
Citation
Li, Ya-Ping, Feng Yuan, Qiang Yuan, Q. Daniel Wang, P. F. Chen, Joseph Neilsen, Taotao Fang, Shuo Zhang, and Jason Dexter. “STATISTICS OF X-RAY FLARES OF SAGITTARIUS A*: EVIDENCE FOR SOLAR-LIKE SELF-ORGANIZED CRITICALITY PHENOMENA.” The Astrophysical Journal 810, no. 1 (August 25, 2015): 19. © 2015 The American Astronomical Society
Version
Final published version
Abstract
X-ray flares have routinely been observed from the supermassive black hole at our Galactic center, Sagittarius A⋆ (Sgr A⋆). The nature of these flares remains largely unclear, despite many theoretical models. In this paper, we study the statistical properties of the Sgr A⋆ X-ray flares by fitting the count rate (CR) distribution and the structure function of the light curve with a Markov Chain Monte Carlo method. With the 3-million-second Chandra observations accumulated in the Sgr A⋆ X-ray Visionary Project, we construct the theoretical light curves through Monte Carlo simulations. We find that the 2–8 keV X-ray light curve can be decomposed into a quiescent component with a constant CR of 6 X 10[superscript -3] count s[superscript −1] and a flare component with a power-law fluence distribution dN/dE ∝ E[superscript -αE] with α[subscript E] = 1.65 ± 0.17. The duration–fluence correlation can also be modeled as a power law T ∝ E[superscript αET] with α[subscript ET] < 0.55 (95% confidence). These statistical properties are consistent with the theoretical prediction of the self-organized criticality system with the spatial dimension S = 3. We suggest that the X-ray flares represent plasmoid ejections driven by magnetic reconnection (similar to solar flares) in the accretion flow onto the black hole.
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1088/0004-637x/810/1/19
