Bibcode
García Pérez, A. E.; Johnson, Jennifer; Allende-Prieto, C.; Cunha, Katia M. L.; Hearty, Fred; Holtzman, Jon A.; Majewski, Steven R.; Nidever, David L.; Schiavon, Ricardo P.; Sobeck, Jennifer; Zasowski, Gail
Bibliographical reference
American Astronomical Society, AAS Meeting #225, #319.06
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1
2015
Citations
0
Refereed citations
0
Description
An important part of the history of the Milky Way is encoded in the
dynamics and chemistry of the inner Galaxy, which contains about 30% of
its mass. It is only in the last few years that a composite picture of
the bulge has begun to emerge: recent evidence points towards a
population made of multiple components. The origin of the bulge appears
to be in the disk and the disk-instabilities, although a component
associated with mergers (a classical bulge) may also exist. The
high-resolution (R=22,500), near-infrared (H-band) SDSS-III/APOGEE-1
survey provides a more complete characterization of the entire bulge as
it penetrates the dust and probes down to the Galactic plane. APOGEE-1
collected spectra for approximately 15,000 inner Galaxy stars and
derived the associated chemical composition data via an automated
spectral analysis based on accurate stellar spectra models. Our
statistical analysis of the highly accurate (~0.1 dex) bulge
metallicities confirms the presence of multiple bulge components, which
change in proportion to each other as a function of height from the
plane. There are two metal-rich components that seem to dissipate in our
high latitude fields (b ≥ 12o), and the metal-poor
components become very weak at low latitude (|b| < 4o). We
are analyzing and comparing the individual element abundances for this
sample (which includes α and C, among other elements) to that of
other Galactic components. This enhances the characterization of the
bulge and permits a thorough exploration of the origin and formation of
its component populations (e.g., a classical bulge or a thick disk
component).