TY - JOUR
T1 - PAndAS' CUBS: Discovery of Two New Dwarf Galaxies in the Surroundings of the Andromeda and Triangulum Galaxies
AU - Martin, Nicolas F.
AU - McConnachie, Alan W.
AU - Irwin, Mike
AU - Widrow, Lawrence M.
AU - Ferguson, Annette M. N.
AU - Ibata, Rodrigo A.
AU - Dubinski, John
AU - Babul, Arif
AU - Chapman, Scott
AU - Fardal, Mark
AU - Lewis, Geraint F.
AU - Navarro, Julio
AU - Rich, R. Michael
PY - 2009/11/1
Y1 - 2009/11/1
N2 - We present the discovery of two new dwarf galaxies, Andromeda XXI and
Andromeda XXII, located in the surroundings of the Andromeda and
Triangulum galaxies (M31 and M33). These discoveries stem from the first
year data of the Pan-Andromeda Archaeological Survey, a photometric
survey of the M31/M33 group conducted with the Megaprime/MegaCam
Wide-Field Camera mounted on the Canada-France-Hawaii Telescope. Both
satellites appear as spatial overdensities of stars which, when plotted
in a color-magnitude diagram, follow metal-poor, [Fe/H] = -1.8, red
giant branches at the distance of M31/M33. Andromeda XXI is a moderately
bright dwarf galaxy (MV = -9.9 ± 0.6), albeit with low
surface brightness, emphasizing again that many relatively luminous M31
satellites still remain to be discovered. It is also a large satellite,
with a half-light radius close to 1 kpc, making it the fourth largest
Local Group dwarf spheroidal galaxy after the recently discovered
Andromeda XIX, Andromeda II, and Sagittarius around the Milky Way, and
supports the trend that M31 satellites are larger than their Milky Way
counterparts. Andromeda XXII is much fainter (MV = -6.5
± 0.8) and lies a lot closer in projection to M33 than it does to
M31 (42 versus 224 kpc), suggesting that it could be the first
Triangulum satellite to be discovered. Although this is a very exciting
possibility in the context of a past interaction of M33 with M31 and the
fate of its satellite system, a confirmation will have to await a good
distance estimate to confirm its physical proximity to M33. Along with
the dwarf galaxies found in previous surveys of the M31 surroundings,
these two new satellites bring the number of dwarf spheroidal galaxies
in this region to 20.
Based on observations obtained with MegaPrime/MegaCam, a joint project
of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT)
which is operated by the National Research Council (NRC) of Canada, the
Institute National des Sciences de l'Univers of the Centre National de
la Recherche Scientifique of France, and the University of Hawaii.
AB - We present the discovery of two new dwarf galaxies, Andromeda XXI and
Andromeda XXII, located in the surroundings of the Andromeda and
Triangulum galaxies (M31 and M33). These discoveries stem from the first
year data of the Pan-Andromeda Archaeological Survey, a photometric
survey of the M31/M33 group conducted with the Megaprime/MegaCam
Wide-Field Camera mounted on the Canada-France-Hawaii Telescope. Both
satellites appear as spatial overdensities of stars which, when plotted
in a color-magnitude diagram, follow metal-poor, [Fe/H] = -1.8, red
giant branches at the distance of M31/M33. Andromeda XXI is a moderately
bright dwarf galaxy (MV = -9.9 ± 0.6), albeit with low
surface brightness, emphasizing again that many relatively luminous M31
satellites still remain to be discovered. It is also a large satellite,
with a half-light radius close to 1 kpc, making it the fourth largest
Local Group dwarf spheroidal galaxy after the recently discovered
Andromeda XIX, Andromeda II, and Sagittarius around the Milky Way, and
supports the trend that M31 satellites are larger than their Milky Way
counterparts. Andromeda XXII is much fainter (MV = -6.5
± 0.8) and lies a lot closer in projection to M33 than it does to
M31 (42 versus 224 kpc), suggesting that it could be the first
Triangulum satellite to be discovered. Although this is a very exciting
possibility in the context of a past interaction of M33 with M31 and the
fate of its satellite system, a confirmation will have to await a good
distance estimate to confirm its physical proximity to M33. Along with
the dwarf galaxies found in previous surveys of the M31 surroundings,
these two new satellites bring the number of dwarf spheroidal galaxies
in this region to 20.
Based on observations obtained with MegaPrime/MegaCam, a joint project
of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT)
which is operated by the National Research Council (NRC) of Canada, the
Institute National des Sciences de l'Univers of the Centre National de
la Recherche Scientifique of France, and the University of Hawaii.
UR - http://www.scopus.com/inward/record.url?scp=70649091229&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/705/1/758
DO - 10.1088/0004-637X/705/1/758
M3 - Article
SN - 0004-637X
VL - 705
SP - 758
EP - 765
JO - Astrophysical Journal
JF - Astrophysical Journal
ER -