Galactic Center
Encyclopedia : G : GA : GAL : Galactic Center
The Galactic Center is the rotational center of the Milky Way galaxy. It is located about 8 kiloparsecs (26,000 LY) away from the Earth (the exact centre of the galaxy may lie closer to 35,000 light-years from Earth/Sol), in the direction of the constellation Sagittarius, where the Milky Way appears brightest.
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.
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 (in silhouette, of course) 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 supernovas 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 -29ยบ 00' 28.1" (J2000 epoch).
See also
External links
- [UCLA Galactic Center Group]
- [Max Planck Institute for Extraterrestrial Physics Galactic Center Group]
- [Dramatic Increase in Supernova Explosions Looms]
| Milky Way |
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Galactic Core: Center of the Milky Way Spiral Arms: Carina Arm | Crux Arm | Cygnus Arm | Norma Arm | Orion Arm | Perseus Arm | Sagittarius Arm | Scutum Arm |
| Location: Universe | Virgo Supercluster | Local Group |
| Satellite galaxies: Canis Major Dwarf Galaxy | Carina Dwarf | Draco Dwarf | Fornax Dwarf | Large Magellanic Cloud | Leo I | Leo II | Sag DEG | Sculptor Dwarf Galaxy | Sextans Dwarf | Small Magellanic Cloud | Virgo Stellar Stream | Ursa Minor Dwarf |
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