Artist's impression of the Milky Way (updated - annotated)

The Far 3 kpc Arm was discovered in 2008 by astronomer

Tom Dame Thomas M. Dame is Director of the Radio Telescope Data Center at the Center for Astrophysics Harvard & Smithsonian, a Senior Radio Astronomer at the Smithsonian Astrophysical Observatory, and a Lecturer on Astronomy at Harvard University. He is ...

( Center for Astrophysics Harvard & Smithsonian), while preparing a talk on the galaxy's

spiral arms Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''American Astronomical Society. It is one of

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

's spiral arms and it is located in the first

galactic quadrant A galactic quadrant, or quadrant of the Galaxy, is one of four circular sectors in the division of the Milky Way Galaxy. Quadrants in the galactic coordinate system In actual astronomical practice, the delineation of the galactic quadrants ...

at a distance of from the

Galactic Center The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact ra ...

. Along with the Near 3 kpc Arm, the existence of which has been known since the mid-1950s, the counterpart inner arms establish our Galaxy's simple symmetry. Tom Dame and collaborator

Patrick Thaddeus Patrick Thaddeus (June 6, 1932 – April 28, 2017) was an American professor and the Robert Wheeler Willson Professor of Applied Astronomy Emeritus at Harvard University. He is best known for mapping carbon monoxide in the Milky Way galaxy and was ...

analyzed data obtained using a 1.2-meter-diameter millimeter-wave

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observ ...

located at

Cerro Tololo Inter-American Observatory The Cerro Tololo Inter-American Observatory (CTIO) is an astronomical observatory located on Cerro Tololo in the Coquimbo Region of northern Chile, with additional facilities located on Cerro Pachón about to the southeast. It is approximately ...

(CTIO) in Chile. They detected the presence of the spiral arm in a CO survey and later confirmed their discovery using 21-centimeter radio measurements of atomic hydrogen collected by colleagues in Australia.A New Spiral Arm of the Galaxy: The Far 3-Kpc Arm
T. M. Dame, P. Thaddeus, ApJ Letters, 2008

References

{{Portal bar, Stars, Spaceflight, Outer space, Solar System Milky Way arms Galactic astronomy Spiral galaxies

See also

References