This composite image shows a powerful microquasar containing a black hole in the outskirts of the nearby (12.7 million light years) galaxy NGC 7793. The large image contains data from the Chandra X-ray Observatory in red, green and blue, optical data from the Very Large Telescope in light blue, and optical emission by hydrogen ("H-alpha") from the CTIO 1.5-m telescope in gold.
The upper inset shows a close-up of the X-ray image of the microquasar, which is a system containing a stellar-mass black hole being fed by a companion star. Gas swirling toward the black hole forms a disk around the black hole. Twisted magnetic fields in the disk generate strong electromagnetic forces that propel some of the gas away from the disk at high speeds in two jets, creating a huge bubble of hot gas about 1,000 light years across. The faint green/blue source near the middle of the upper inset image corresponds to the position of the black hole, while the red/yellow (upper right) and yellow (lower left) sources correspond to spots where the jets are plowing into surrounding gas and heating it. The nebula produced by energy from the jets is clearly seen in the H-alpha image shown in the lower inset.
The jets in the NGC 7793 microquasar are the most powerful ever seen from a stellar-mass black hole and the data show that a surprising amount of energy from the black hole is being carried away by the jets, rather than by radiation from material being pulled inward. The power of the jets is estimated to be about ten times larger than that of the very powerful ones seen from the famous microquasar in our own galaxy, SS433. This system in NGC 7793 is a miniature version of the powerful quasars and radio galaxies, which contain black holes that range from millions to billions of times the mass of the Sun.
A paper describing this work is being published in the July 8th, 2010, issue of Nature. The authors are Manfred Pakull from the University of Strasbourg in France, Roberto Soria from University College London, and Christian Motch, also from the University of Strasbourg.
A 3-panel image of the galaxy NGC 7793 is a combination of X-ray and optical images. The dominant colors in this image are blue-green, and yellow. The shape of the galaxy in the left panel appears to be a very irregular spiral-like shape, with many bright spots of light scattered all through and around it. The 2 smaller images at right show a powerful microquasar - labelled at 11 o’clock in the galaxy at left. It contains a black hole in the outskirts of the nearby (12.7 million light years away) galaxy NGC 7793. The large image at left contains data from the Chandra X-ray Observatory in red, green and blue, optical data from the Very Large Telescope in light blue, and optical emission by hydrogen ("H-alpha") from the CTIO 1.5-m telescope in gold. The upper right inset shows a close-up of the X-ray image of the microquasar, which is a system containing a stellar-mass black hole being fed by a companion star. The image resembles a colorful twisting worm. Gas swirling toward the black hole forms a disk around the black hole. Twisted magnetic fields in the disk generate strong electromagnetic forces that propel some of the gas away from the disk at high speeds in two jets, creating a huge bubble of hot gas about 1,000 light years across. A faint green/blue source near the middle of the upper inset image corresponds to the position of the black hole, while the red/yellow (upper right) and yellow (lower left) sources correspond to spots where the jets are plowing into surrounding gas and heating it. The nebula produced by energy from the jets is clearly seen in the H-alpha image shown in the lower inset. In the X-ray image, the galaxy appears to be surrounded by a cloud of gas, while the optical image highlights the galaxy's spiral structure. The X-ray image reveals the presence of a supermassive black hole at the center of the galaxy, which is accreting material from its surroundings. This black hole is estimated to have a mass of several hundred million times that of our sun, making it one of the most massive black holes known in the Milky Way galaxy.
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