A MAJOR X-RAY OUTBURST FROM AN ULTRALUMINOUS X-RAY SOURCE IN M82

作者：Kaaret Philip^*; Feng Hua; Gorski Mark

来源：Astrophysical Journal, 2009, 692(1): 653-658.

DOI：10.1088/0004-637X/692/1/653

• black hole physics
• galaxies: individual (M82)
• galaxies: stellar content
• X-rays: binaries
• X-rays: galaxies

We detected amajor X-ray outburst from M82 with a duration of 79 days, an average flux of 5x10(-11) erg cm(-2) s(-1) in the 2-10 keV band, and strong variability. The X-ray spectrum remained hard throughout the outburst. We obtained a Chandra observation during the outburst that shows that the emission arises from the ultraluminous X-ray source X41.4 60. This source has an unabsorbed flux of (5.4 /- 0.2) x10(-11) erg cm(-2) s(-1) in the 0.3-8 kcV band, equivalent to an isotropic luminosity of 8.5x10(40) erg s(-1). The spectrum is adequately fitted with an absorbed power law with a photon index of 1.55 /- 0.05. This photon index is very similar to the value of 1.61 /- 0.06 measured previously while the flux was (2.64 /- 0.14) x 10(-11) erg cm(-2) s(-1). Thus, the source appears to remain in the hard state even at the highest flux levels observed. The X-ray spectral and timing data available for X41.4 60 are consistent with the source being in a luminous hard state and a black hole mass in the range of one to a few thousand solar masses.

• 出版日期2009-2-10
• 单位清华大学