Repeated X-ray flaring activity in Sagittarius A

G. Bélanger, A. Goldwurm, Fulvio Melia, P. Ferrando, N. Grosso, D. Porquet, R. Warwick, F. Yusef-Zadeh

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms in this supermassive black hole located at the center of our Galaxy. Several X-ray flares with varying durations and spectral features have already been observed from this object. Here we present the results of two long XMM-Newton observations of the Galactic nucleus carried out in 2004, for a total exposure time of nearly 500 ks. During these observations we detected two flares from Sgr A* with peak 2-10 keV luminosities about 40 times (LX ∼ 9 × 1034 ergs s-1) above the quiescent luminosity: one on 2004 March 31 and another on 2004 August 31. The total duration of the first flare was about 4 ks. The second, simultaneously detected in the near-IR, lasted about 10 ks. The combined fit to the EPIC spectra yields photon indices of about 1.5 and 1.9 for the first and second flares, respectively. This hard photon index strongly suggests the presence of an important population of nonthermal electrons during the event and supports the view that the majority of flaring events tend to be hard and not very luminous.

Original languageEnglish (US)
Pages (from-to)1095-1102
Number of pages8
JournalAstrophysical Journal
Volume635
Issue number2 I
DOIs
StatePublished - Dec 20 2005

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flares
erg
x rays
luminosity
galactic nuclei
electron
photons
XMM-Newton telescope
newton
galaxies
flaring
index
electrons
exposure

Keywords

  • Black hole physics
  • Galaxy: center
  • Galaxy: nucleus
  • Stars: neutron
  • X-rays: binaries
  • X-rays: general

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Bélanger, G., Goldwurm, A., Melia, F., Ferrando, P., Grosso, N., Porquet, D., ... Yusef-Zadeh, F. (2005). Repeated X-ray flaring activity in Sagittarius A. Astrophysical Journal, 635(2 I), 1095-1102. https://doi.org/10.1086/497624

Repeated X-ray flaring activity in Sagittarius A. / Bélanger, G.; Goldwurm, A.; Melia, Fulvio; Ferrando, P.; Grosso, N.; Porquet, D.; Warwick, R.; Yusef-Zadeh, F.

In: Astrophysical Journal, Vol. 635, No. 2 I, 20.12.2005, p. 1095-1102.

Research output: Contribution to journalArticle

Bélanger, G, Goldwurm, A, Melia, F, Ferrando, P, Grosso, N, Porquet, D, Warwick, R & Yusef-Zadeh, F 2005, 'Repeated X-ray flaring activity in Sagittarius A', Astrophysical Journal, vol. 635, no. 2 I, pp. 1095-1102. https://doi.org/10.1086/497624
Bélanger G, Goldwurm A, Melia F, Ferrando P, Grosso N, Porquet D et al. Repeated X-ray flaring activity in Sagittarius A. Astrophysical Journal. 2005 Dec 20;635(2 I):1095-1102. https://doi.org/10.1086/497624
Bélanger, G. ; Goldwurm, A. ; Melia, Fulvio ; Ferrando, P. ; Grosso, N. ; Porquet, D. ; Warwick, R. ; Yusef-Zadeh, F. / Repeated X-ray flaring activity in Sagittarius A. In: Astrophysical Journal. 2005 ; Vol. 635, No. 2 I. pp. 1095-1102.
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