GRS 1124-683
Encyclopedia
The gamma-ray and X-ray source GRS 1124-683, discovered by the Granat
mission and Ginga, is a system containing a black hole
candidate. The system also goes by the name X-ray Nova Muscae 1991 or GU Mus. These two orbiting X-ray telescopes discovered GU Muscae when the system produced an outburst of X-rays on January 9, 1991.
In such a system, a black hole pulls gas from the surface of a companion star. The gas forms a thin disk around the black hole, known as an accretion disk. In an X-ray nova, the flow of gas is fairly thin and slow, so the accretion disk remains relatively cool, and little gas falls into the black hole.
In the case of GU Muscae, the black hole is about seven times as massive as the Sun, while the companion is three-quarters as massive as the Sun. The companion is also cooler than the Sun, so its surface is redder, and the star's total luminosity is only one-third that of the Sun's. Its outer layers probably were blown away by the supernova explosion that gave birth to the black hole. The two stars orbit each other every 10.4 hours at a distance of roughly 2 million miles (3.2 million km).
detected a relatively narrow variable emission line near 500 keV in the spectrum. From January 9-August 14, 1991, the spectrum had a strong hard component extending up to ∼300 keV.
Granat
The International Astrophysical Observatory "GRANAT" , was a Soviet space observatory developed in collaboration with France, Denmark and Bulgaria. It was launched on 1 December 1989 aboard a Proton rocket and placed in a highly eccentric four-day orbit, of which three were devoted to observations...
mission and Ginga, is a system containing a black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
candidate. The system also goes by the name X-ray Nova Muscae 1991 or GU Mus. These two orbiting X-ray telescopes discovered GU Muscae when the system produced an outburst of X-rays on January 9, 1991.
Black hole system
It is one of several likely black hole systems that are classified as X-ray novae. Such a nova periodically produces bright outbursts of X-rays, along with visible light and other forms of energy.In such a system, a black hole pulls gas from the surface of a companion star. The gas forms a thin disk around the black hole, known as an accretion disk. In an X-ray nova, the flow of gas is fairly thin and slow, so the accretion disk remains relatively cool, and little gas falls into the black hole.
In the case of GU Muscae, the black hole is about seven times as massive as the Sun, while the companion is three-quarters as massive as the Sun. The companion is also cooler than the Sun, so its surface is redder, and the star's total luminosity is only one-third that of the Sun's. Its outer layers probably were blown away by the supernova explosion that gave birth to the black hole. The two stars orbit each other every 10.4 hours at a distance of roughly 2 million miles (3.2 million km).
Spectral radiance
During the January 20–21, 1991, outburst which led to its discovery, radiation was produced by positron annihilation. The SIGMA telescope aboard GRANATGranat
The International Astrophysical Observatory "GRANAT" , was a Soviet space observatory developed in collaboration with France, Denmark and Bulgaria. It was launched on 1 December 1989 aboard a Proton rocket and placed in a highly eccentric four-day orbit, of which three were devoted to observations...
detected a relatively narrow variable emission line near 500 keV in the spectrum. From January 9-August 14, 1991, the spectrum had a strong hard component extending up to ∼300 keV.