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EspañolGALACTIC CENTER
(Redirected from Galactic center)
The 'Galactic Center' is the rotational center of the Milky Way galaxy. It is located about 7.6 kiloparsecs (24,800 LY) away from the Earth,[1] in the direction of the constellation Sagittarius, where the Milky Way appears brightest. Scientists hypothesize that a supermassive black hole lies in the Galactic Center of the Milky Way, and most (if not all) other galaxies.
Because of cool interstellar dust along the line of sight, the Galactic Center cannot be studied at visible, ultraviolet or soft X-ray wavelengths. The available information about the Galactic Center comes from observations at gamma ray, hard X-ray, infrared, sub-millimetre and radio wavelengths.
Coordinates of Galactic Center were first found by Harlow Shapley in his 1918 study of the distribution of the globular clusters.
The complex radio source Sagittarius A appears to be located almost exactly at the Galactic Center, and contains an intense compact radio source, Sagittarius A
★ , which many astronomers believe may coincide with a supermassive black hole at the center of our Galaxy. Accretion of gas onto the black hole, probably involving a disk around it, would release energy to power the radio source, itself much larger than the black hole. The latter is too small to see with present instruments.
Work presented in 2002 by Antony Stark and Chris Martin mapping the gas density in a 400 light year region around the galactic center has revealed an accumulating ring with a mass several million times that of the Sun and near the critical density for star formation. They predict that in approximately 200 million years there will be an episode of starburst in the galactic center, with many stars forming rapidly and undergoing supernovae at a hundred times the current rate. The starburst may also be accompanied by the formation of galactic jets as matter falls into the central black hole. It is thought that the Milky Way undergoes a starburst of this sort every 500 million years.
The coordinates of Galactic Center in the Equatorial coordinate system are: RA 17h45m40.04s, Dec -29º 00' 28.1" (J2000 epoch).
★ Galactic coordinate system
★ Melia, Fulvio, The Black Hole in the Center of Our Galaxy, Princeton U Press, 2003
★ Eckart, A., Schödel, R., Straubmeier, C., The Black Hole at the Center of the Milky Way, Imperial College Press, London, 2005
★ Melia, Fulvio, The Galactic Supermassive Black Hole, Princeton U Press, 2007
1. SINFONI in the Galactic Center: young stars and IR flares in the central light month, , , , ,
★ The Galactic Supermassive Black Hole
★ The Black Hole at the Center of the Milky Way
★ UCLA Galactic Center Group
★ Max Planck Institute for Extraterrestrial Physics Galactic Center Group
★ Slideshow on the galactic center (-broken link-)
★ Dramatic Increase in Supernova Explosions Looms
★ APOD:
★
★ Journey to the Center of the Galaxy
★
★ A Galactic Cloud of Antimatter
★
★ Fast Stars Near the Galactic Center
★
★ At the Center of the Milky Way
★
★ Galactic Centre Starscape
The 'Galactic Center' is the rotational center of the Milky Way galaxy. It is located about 7.6 kiloparsecs (24,800 LY) away from the Earth,[1] in the direction of the constellation Sagittarius, where the Milky Way appears brightest. Scientists hypothesize that a supermassive black hole lies in the Galactic Center of the Milky Way, and most (if not all) other galaxies.
The Galactic Center as seen by the 2MASS infrared space telescope.
| Contents |
| Proof of existence and location |
| Predictions |
| See also |
| Further reading |
| References |
| External links |
Proof of existence and location
Because of cool interstellar dust along the line of sight, the Galactic Center cannot be studied at visible, ultraviolet or soft X-ray wavelengths. The available information about the Galactic Center comes from observations at gamma ray, hard X-ray, infrared, sub-millimetre and radio wavelengths.
Coordinates of Galactic Center were first found by Harlow Shapley in his 1918 study of the distribution of the globular clusters.
The complex radio source Sagittarius A appears to be located almost exactly at the Galactic Center, and contains an intense compact radio source, Sagittarius A
★ , which many astronomers believe may coincide with a supermassive black hole at the center of our Galaxy. Accretion of gas onto the black hole, probably involving a disk around it, would release energy to power the radio source, itself much larger than the black hole. The latter is too small to see with present instruments.
Predictions
Work presented in 2002 by Antony Stark and Chris Martin mapping the gas density in a 400 light year region around the galactic center has revealed an accumulating ring with a mass several million times that of the Sun and near the critical density for star formation. They predict that in approximately 200 million years there will be an episode of starburst in the galactic center, with many stars forming rapidly and undergoing supernovae at a hundred times the current rate. The starburst may also be accompanied by the formation of galactic jets as matter falls into the central black hole. It is thought that the Milky Way undergoes a starburst of this sort every 500 million years.
The coordinates of Galactic Center in the Equatorial coordinate system are: RA 17h45m40.04s, Dec -29º 00' 28.1" (J2000 epoch).
See also
★ Galactic coordinate system
Further reading
★ Melia, Fulvio, The Black Hole in the Center of Our Galaxy, Princeton U Press, 2003
★ Eckart, A., Schödel, R., Straubmeier, C., The Black Hole at the Center of the Milky Way, Imperial College Press, London, 2005
★ Melia, Fulvio, The Galactic Supermassive Black Hole, Princeton U Press, 2007
References
1. SINFONI in the Galactic Center: young stars and IR flares in the central light month, , , , ,
External links
★ The Galactic Supermassive Black Hole
★ The Black Hole at the Center of the Milky Way
★ UCLA Galactic Center Group
★ Max Planck Institute for Extraterrestrial Physics Galactic Center Group
★ Slideshow on the galactic center (-broken link-)
★ Dramatic Increase in Supernova Explosions Looms
★ APOD:
★
★ Journey to the Center of the Galaxy
★
★ A Galactic Cloud of Antimatter
★
★ Fast Stars Near the Galactic Center
★
★ At the Center of the Milky Way
★
★ Galactic Centre Starscape
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