TY - JOUR
T1 - The apache point observatory galactic evolution experiment
T2 - First detection of high-velocity milky way bar stars
AU - Nidever, David L.
AU - Zasowski, Gail
AU - Majewski, Steven R.
AU - Bird, Jonathan
AU - Robin, Annie C.
AU - Martinez-Valpuesta, Inma
AU - Beaton, Rachael L.
AU - Schönrich, Ralph
AU - Schultheis, Mathias
AU - Wilson, John C.
AU - Skrutskie, Michael F.
AU - O'Connell, Robert W.
AU - Shetrone, Matthew
AU - Schiavon, Ricardo P.
AU - Johnson, Jennifer A.
AU - Weiner, Benjamin
AU - Gerhard, Ortwin
AU - Schneider, Donald P.
AU - Allende Prieto, Carlos
AU - Sellgren, Kris
AU - Bizyaev, Dmitry
AU - Brewington, Howard
AU - Brinkmann, Jon
AU - Eisenstein, Daniel J.
AU - Frinchaboy, Peter M.
AU - García Pérez, Ana Elia
AU - Holtzman, Jon
AU - Hearty, Fred R.
AU - Malanushenko, Elena
AU - Malanushenko, Viktor
AU - Muna, Demitri
AU - Oravetz, Daniel
AU - Pan, Kaike
AU - Simmons, Audrey
AU - Snedden, Stephanie
AU - Weaver, Benjamin A.
PY - 2012/8/20
Y1 - 2012/8/20
N2 - Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for 4700K/M-giant stars in the Milky Way (MW) bulge. These high-resolution (R 22, 500), high-S/N (>100 per resolution element), near-infrared (NIR; 1.51-1.70 μm) spectra provide accurate RVs (εV 0.2kms-1) for the sample of stars in 18 Galactic bulge fields spanning -1° -32°. This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold (σV 30kms-1), high-velocity peak (V GSR ≈ +200kms-1) is found to comprise a significant fraction (10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galactic models suggests that these high RVs are best explained by stars in orbits of the Galactic bar potential, although some observational features remain unexplained.
AB - Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for 4700K/M-giant stars in the Milky Way (MW) bulge. These high-resolution (R 22, 500), high-S/N (>100 per resolution element), near-infrared (NIR; 1.51-1.70 μm) spectra provide accurate RVs (εV 0.2kms-1) for the sample of stars in 18 Galactic bulge fields spanning -1° -32°. This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold (σV 30kms-1), high-velocity peak (V GSR ≈ +200kms-1) is found to comprise a significant fraction (10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galactic models suggests that these high RVs are best explained by stars in orbits of the Galactic bar potential, although some observational features remain unexplained.
KW - Galaxy: bulge
KW - Galaxy: kinematics and dynamics
KW - Galaxy: structure
KW - surveys
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U2 - 10.1088/2041-8205/755/2/L25
DO - 10.1088/2041-8205/755/2/L25
M3 - Article
AN - SCOPUS:84865003926
SN - 2041-8205
VL - 755
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L25
ER -