Anticenter shell

The Anti-center shell is the name of a region in space emitting 21 cm radiation near the anticenter of the Milky Way Galaxy in the constellation Auriga. It is located at RA|06|27 DEC|-15, or l = 197°, b = +2° in galactic coordinates. It is a galactic supershell (that is, a very large superbubble) within our galaxy which is spherical in shape and features jets of gas. The shell has been variously referred to as a depleted dwarf galaxy or Milky Way spiral arm in research since the feature was first observed in the 1970's. cite journal
last= Tamanaha
first= Christopher M.
journal= Astrophysical Journal Supplement Series
title= The Anticenter Shell and the Anticenter Chain
url= http://www.journals.uchicago.edu/doi/full/10.1086/312975
doi= 10.1086/312975 | volume=109 | pages=139
year=1997
accessdate= 2008-04-04]

Discovered in 1970, this galactic object was subsequently claimed to be a spiral arm in 1972, a tidally-striped galaxy in 1975, and then a high-velocity cloud in 1979.

The Milky Way's anticenter shell was described in 1975 by Christian Simonson, a University of Maryland astronomer who believed it to be a small "peanut" of a galaxy.cite journal
last = Simonson
first = S. Christian, III.
authorlink =
coauthors =
title = A New Milky Way Satellite Found in 21-Centimeter Line Observations
journal = Astrophysical Journal Letters
volume = 201
issue =
pages = L103–L108
publisher =
location =
year=1975
url = http://adsabs.harvard.edu/abs/1975ApJ...201L.103S
doi =
id =
accessdate = 2008-04-04 ] [cite web
title = Snickers
work = Astroprof's Page
date = 2006-02-28
url = http://astroprofspage.com/archives/117
accessdate = 2008-02-01] Simonson's colleagues named it Snickers due to its proximity to the Milky Way, in reference to the American chocolate bars "Milky Way" and "Snickers". Less popularly, the galaxy's anticenter superbubble is also referred to by its succinct coordinates, 0627—15.Citation
title = Peanuts in the Sky
newspaper = Time
date = 1975-11-24
url = http://www.time.com/time/magazine/article/0,9171,913757,00.html
accessdate = 2008-02-01]

Astronomical measurement of its dimensions by radio observation is difficult due to its location near a zone of avoidance, the regions of the sky obscured by interstellar dust. The anticenter shell is approximately 55,000 light years from earth.Fact|date=June 2008

References