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Title: NEW EVIDENCE FOR HIGH ACTIVITY OF THE SUPERMASSIVE BLACK HOLE IN OUR GALAXY

Abstract

Prominent K-shell emission lines of neutral iron (hereafter Fe I-K lines) and hard-continuum X-rays from molecular clouds (MCs) in the Sagittarius B (Sgr B) region were found in two separate Suzaku observations in 2005 and 2009. The X-ray flux of the Fe I-K lines decreased in correlation with the hard-continuum flux by a factor of 0.4-0.5 in four years, which is almost equal to the light traveling across the MCs. The rapid and correlated time variability, the equivalent width of the Fe I-K lines, and the K edge absorption depth of Fe I are consistently explained by 'X-ray echoes' due to the fluorescent and Thomson scattering of an X-ray flare from an external source. The required flux of the X-ray flare depends on the distance to the MCs and its time duration. Even for a case with a minimum distance, the flux is larger than those of the brightest Galactic X-ray sources. Based on these facts, we conclude that the supermassive black hole Sgr A* exhibited a large flare a few hundred years ago with a luminosity of more than 4 x 10{sup 39} erg s{sup -1}. The 'X-ray echo' from Sgr B, located a few hundred light-years from Sgrmore » A*, has now reached the Earth.« less

Authors:
; ; ;  [1]
  1. Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)
Publication Date:
OSTI Identifier:
21565428
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 739; Journal Issue: 2; Other Information: DOI: 10.1088/2041-8205/739/2/L52; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; FLUORESCENCE; GALAXIES; IRON; K SHELL; THOMSON SCATTERING; X RADIATION; ELECTROMAGNETIC RADIATION; ELECTRONIC STRUCTURE; ELEMENTS; EMISSION; INELASTIC SCATTERING; IONIZING RADIATIONS; LUMINESCENCE; METALS; PHOTON EMISSION; RADIATIONS; SCATTERING; TRANSITION ELEMENTS

Citation Formats

Nobukawa, M., Ryu, S. G., Tsuru, T. G., and Koyama, K., E-mail: nobukawa@cr.scphys.kyoto-u.ac.jp. NEW EVIDENCE FOR HIGH ACTIVITY OF THE SUPERMASSIVE BLACK HOLE IN OUR GALAXY. United States: N. p., 2011. Web. doi:10.1088/2041-8205/739/2/L52.
Nobukawa, M., Ryu, S. G., Tsuru, T. G., & Koyama, K., E-mail: nobukawa@cr.scphys.kyoto-u.ac.jp. NEW EVIDENCE FOR HIGH ACTIVITY OF THE SUPERMASSIVE BLACK HOLE IN OUR GALAXY. United States. doi:10.1088/2041-8205/739/2/L52.
Nobukawa, M., Ryu, S. G., Tsuru, T. G., and Koyama, K., E-mail: nobukawa@cr.scphys.kyoto-u.ac.jp. Sat . "NEW EVIDENCE FOR HIGH ACTIVITY OF THE SUPERMASSIVE BLACK HOLE IN OUR GALAXY". United States. doi:10.1088/2041-8205/739/2/L52.
@article{osti_21565428,
title = {NEW EVIDENCE FOR HIGH ACTIVITY OF THE SUPERMASSIVE BLACK HOLE IN OUR GALAXY},
author = {Nobukawa, M. and Ryu, S. G. and Tsuru, T. G. and Koyama, K., E-mail: nobukawa@cr.scphys.kyoto-u.ac.jp},
abstractNote = {Prominent K-shell emission lines of neutral iron (hereafter Fe I-K lines) and hard-continuum X-rays from molecular clouds (MCs) in the Sagittarius B (Sgr B) region were found in two separate Suzaku observations in 2005 and 2009. The X-ray flux of the Fe I-K lines decreased in correlation with the hard-continuum flux by a factor of 0.4-0.5 in four years, which is almost equal to the light traveling across the MCs. The rapid and correlated time variability, the equivalent width of the Fe I-K lines, and the K edge absorption depth of Fe I are consistently explained by 'X-ray echoes' due to the fluorescent and Thomson scattering of an X-ray flare from an external source. The required flux of the X-ray flare depends on the distance to the MCs and its time duration. Even for a case with a minimum distance, the flux is larger than those of the brightest Galactic X-ray sources. Based on these facts, we conclude that the supermassive black hole Sgr A* exhibited a large flare a few hundred years ago with a luminosity of more than 4 x 10{sup 39} erg s{sup -1}. The 'X-ray echo' from Sgr B, located a few hundred light-years from Sgr A*, has now reached the Earth.},
doi = {10.1088/2041-8205/739/2/L52},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 2,
volume = 739,
place = {United States},
year = {2011},
month = {10}
}