Exploring the Stellar Age Distribution of the Milky Way Bulge Using APOGEE
Name:
Hasselquist_2020_ApJ_901_109.pdf
Size:
2.759Mb
Format:
PDF
Description:
Final Published Version
Author
Hasselquist, StenZasowski, Gail
Feuillet, Diane K.
Schultheis, Mathias
Nataf, David M.
Anguiano, Borja
Beaton, Rachael L.
Beers, Timothy C.
Cohen, Roger E.
Cunha, Katia
Fernández-Trincado, José G.
García-Hernández, D. A.
Geisler, Doug
Holtzman, Jon A.
Johnson, Jennifer
Lane, Richard R.
Majewski, Steven R.
Bidin, Christian Moni
Nitschelm, Christian
Roman-Lopes, Alexandre
Schiavon, Ricardo
Smith, Verne V.
Sobeck, Jennifer
Affiliation
Univ Arizona, Steward ObservIssue Date
2020-09-28
Metadata
Show full item recordPublisher
IOP PUBLISHING LTDCitation
Hasselquist, S., Zasowski, G., Feuillet, D. K., Schultheis, M., Nataf, D. M., Anguiano, B., ... & Sobeck, J. (2020). Exploring the stellar age distribution of the Milky Way Bulge using APOGEE. The Astrophysical Journal, 901(2), 109.Journal
ASTROPHYSICAL JOURNALRights
© 2020. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We present stellar age distributions of the Milky Way bulge region using ages for similar to 6000 high-luminosity (log (g), metal-rich ([Fe/H] >= -0.5) bulge stars observed by the Apache Point Observatory Galactic Evolution Experiment. Ages are derived using The Cannon label-transfer method, trained on a sample of nearby luminous giants with precise parallaxes for which we obtain ages using a Bayesian isochrone-matching technique. We find that the metal-rich bulge is predominantly composed of old stars (>8 Gyr). We find evidence that the planar region of the bulge (vertical bar Z(GC)vertical bar <= 0.25 kpc) is enriched in metallicity, Z, at a faster rate (dZ/dt similar to 0.0034 Gyr(-1)) than regions farther from the plane (dZ/dt similar to 0.0013 Gyr(-1) at vertical bar Z(GC)vertical bar > 1.00 kpc). We identify a nonnegligible fraction of younger stars (age similar to 2-5 Gyr) at metallicities of +0.2 < [Fe/H] < +0.4. These stars are preferentially found in the plane (vertical bar Z(GC)vertical bar <= 0.25 kpc) and at R-cy approximate to 2-3 kpc, with kinematics that are more consistent with rotation than are the kinematics of older stars at the same metallicities. We do not measure a significant age difference between stars found inside and outside the bar. These findings show that the bulge experienced an initial starburst that was more intense close to the plane than far from the plane. Then, star formation continued at supersolar metallicities in a thin disk at 2 kpc less than or similar to R-cy less than or similar to 3 kpc until similar to 2 Gyr ago.ISSN
0004-637XEISSN
1538-4357Version
Final published versionae974a485f413a2113503eed53cd6c53
10.3847/1538-4357/abaeee