TY - JOUR
T1 - Sagittarius II, Draco II and Laevens 3: Three New Milky Way Satellites Discovered in the Pan-STARRS 1 3π Survey
AU - Laevens, Benjamin P. M.
AU - Martin, Nicolas F.
AU - Bernard, Edouard J.
AU - Schlafly, Edward F.
AU - Sesar, Branimir
AU - Rix, Hans-Walter
AU - Bell, Eric F.
AU - Ferguson, Annette M. N.
AU - Slater, Colin T.
AU - Sweeney, William E.
AU - Wyse, Rosemary F. G.
AU - Huxor, Avon P.
AU - Burgett, William S.
AU - Chambers, Kenneth C.
AU - Draper, Peter W.
AU - Hodapp, Klaus A.
AU - Kaiser, Nicholas
AU - Magnier, Eugene A.
AU - Metcalfe, Nigel
AU - Tonry, John L.
AU - Wainscoat, Richard J.
AU - Waters, Christopher
PY - 2015/10/27
Y1 - 2015/10/27
N2 - We present the discovery of three new Milky Way satellites from our
search for compact stellar overdensities in the photometric catalog of
the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS
1, or PS1) 3π survey. The first satellite, Laevens 3, is located at a
heliocentric distance of d = 67 ± 3 kpc. With a total magnitude
of MV = -4.4 ± 0.3 and a half-light radius of
rh = 7 ± 2 pc, its properties resemble those of outer
halo globular clusters. The second system, Draco II/Laevens 4, is a
closer and fainter satellite (d ˜ 20 kpc, MV = -2.9
± 0.8), whose uncertain size
({r}h={19}-6+8 {pc}) renders its
classification difficult without kinematic information; it could either
be a faint and extended globular cluster or a faint and compact dwarf
galaxy. The third satellite, Sagittarius II/Laevens 5 (Sgr II), has an
ambiguous nature, as it is either the most compact dwarf galaxy or the
most extended globular cluster in its luminosity range
({r}h={37}-8+9 {pc} and MV =
-5.2 ± 0.4). At a heliocentric distance of 67 ± 5
kpc, this satellite lies intriguingly close to the expected location of
the trailing arm of the Sagittarius stellar stream behind the
Sagittarius dwarf spheroidal galaxy (Sgr dSph). If confirmed through
spectroscopic follow up, this connection would locate this part of the
trailing arm of the Sagittarius stellar stream that has so far gone
undetected. It would further suggest that Sgr II was brought into the
Milky Way halo as a satellite of the Sgr dSph.
AB - We present the discovery of three new Milky Way satellites from our
search for compact stellar overdensities in the photometric catalog of
the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS
1, or PS1) 3π survey. The first satellite, Laevens 3, is located at a
heliocentric distance of d = 67 ± 3 kpc. With a total magnitude
of MV = -4.4 ± 0.3 and a half-light radius of
rh = 7 ± 2 pc, its properties resemble those of outer
halo globular clusters. The second system, Draco II/Laevens 4, is a
closer and fainter satellite (d ˜ 20 kpc, MV = -2.9
± 0.8), whose uncertain size
({r}h={19}-6+8 {pc}) renders its
classification difficult without kinematic information; it could either
be a faint and extended globular cluster or a faint and compact dwarf
galaxy. The third satellite, Sagittarius II/Laevens 5 (Sgr II), has an
ambiguous nature, as it is either the most compact dwarf galaxy or the
most extended globular cluster in its luminosity range
({r}h={37}-8+9 {pc} and MV =
-5.2 ± 0.4). At a heliocentric distance of 67 ± 5
kpc, this satellite lies intriguingly close to the expected location of
the trailing arm of the Sagittarius stellar stream behind the
Sagittarius dwarf spheroidal galaxy (Sgr dSph). If confirmed through
spectroscopic follow up, this connection would locate this part of the
trailing arm of the Sagittarius stellar stream that has so far gone
undetected. It would further suggest that Sgr II was brought into the
Milky Way halo as a satellite of the Sgr dSph.
KW - galaxies: dwarf
KW - Galaxy: structure
KW - globular clusters: general
KW - Local Group
U2 - 10.1088/0004-637X/813/1/44
DO - 10.1088/0004-637X/813/1/44
M3 - Article
VL - 813
SP - 44
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
ER -