| Full text | |
| Author(s): Show less - |
Queiroz, A. B. A.
[1, 2]
;
Chiappini, C.
[1, 2]
;
Perez-Villegas, A.
[3, 4]
;
Khalatyan, A.
[1]
;
Anders, F.
[2, 5]
;
Barbuy, B.
[3]
;
Santiago, B. X.
[6, 2]
;
Steinmetz, M.
[1]
;
Cunha, K.
[7, 8]
;
Schultheis, M.
[9]
;
Majewski, S. R.
[10]
;
Minchev, I
[1]
;
Minniti, D.
[11, 12]
;
Beaton, R. L.
[13]
;
Cohen, R. E.
[14]
;
da Costa, L. N.
[2]
;
Fernandez-Trincado, J. G.
[15, 16]
;
Garcia-Hernandez, D. A.
[17, 18]
;
Geisler, D.
[19, 20, 21]
;
Hasselquist, S.
[22]
;
Lane, R. R.
[16]
;
Nitschelm, C.
[23]
;
Rojas-Arriagada, A.
[24, 25]
;
Roman-Lopes, A.
[21]
;
Smith, V
[26]
;
Zasowski, G.
[22]
Total Authors: 26
|
| Affiliation: Show less - | [1] Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam - Germany
[2] Lab Interinst E Astron LIneA, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, RJ - Brazil
[3] Univ Sao Paulo, Dept Astron, BR-05508090 Sao Paulo - Brazil
[4] Univ Nacl Autonoma Mexico, Inst Astron, AP 106, Ensenada 22800, Baja California - Mexico
[5] Univ Barcelona IEECUB, Inst Ciencies Cosmos, Carrer Marti & Franques 1, Barcelona 08028 - Spain
[6] Univ Fed Rio Grande do Sul, Inst Fis, Caixa Postal 15051, BR-91501970 Porto Alegre, RS - Brazil
[7] Univ Arizona, Tucson, AZ 85719 - USA
[8] Observatorio Nacl, Sao Cristovao, RJ - Brazil
[9] Observ Cote dAzur, Lab Lagrange, F-06304 Nice 4 - France
[10] Univ Virginia, Dept Astron, Charlottesville, VA 22904 - USA
[11] Vatican Observ, I-00120 Vatican City - Vatican
[12] Univ Andres Bello, Fac Exact Sci, Dept Phys Sci, Fernandez Concha 700, Santiago - Chile
[13] Carnegie Observ, 813 Santa Barbara St, Pasadena, CA 91101 - USA
[14] Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 - USA
[15] Univ Catolica Norte, Inst Astron, Av Angamos 0610, Antofagasta - Chile
[16] Univ Atacama, Inst Astron & Ciencias Planetarias Atacama, Copayapu 485, Copiapo - Chile
[17] Inst Astrofis Canarias IAC, Tenerife 38205 - Spain
[18] Univ La Laguna ULL, Dept Astrofis, Tenerife 38206 - Spain
[19] Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion - Chile
[20] Univ La Serena, Inst Invest Multidisciplinario Ciencia & Technol, Ave Raul Bitran S-N, La Serena - Chile
[21] Univ La Serena, Fac Ciencias, Dept Fis, Cisternas 1200, La Serena - Chile
[22] Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 - USA
[23] Univ Antofagasta, Ctr Astron CITEVA, Ave Angamos 601, Antofagasta 1270300 - Chile
[24] Pontificia Univ Catolica Chile, Inst Astrofis, Av Vicuna Mackenna 4860, Santiago 7820436 - Chile
[25] Millennium Inst Astrophys, Av Vicuna Mackenna 4860, Santiago 7820436 - Chile
[26] Natl Opt Astron Observ, Tucson, AZ 85719 - USA
Total Affiliations: 26
|
| Document type: | Journal article |
| Source: | Astronomy & Astrophysics; v. 656, DEC 16 2021. |
| Web of Science Citations: | 1 |
| Abstract | |
We investigate the inner regions of the Milky Way using data from APOGEE and Gaia EDR3. Our inner Galactic sample has more than 26 500 stars within |X-Gal|< 5 kpc, |Y-Gal|< 3.5 kpc, |Z(Gal)|< 1 kpc, and we also carry out the analysis for a foreground-cleaned subsample of 8000 stars that is more representative of the bulge-bar populations. These samples allow us to build chemo-dynamical maps of the stellar populations with vastly improved detail. The inner Galaxy shows an apparent chemical bimodality in key abundance ratios {[}alpha/Fe], {[}C/N], and {[}Mn/O], which probe different enrichment timescales, suggesting a star formation gap (quenching) between the high- and low-alpha populations. Using a joint analysis of the distributions of kinematics, metallicities, mean orbital radius, and chemical abundances, we can characterize the different populations coexisting in the innermost regions of the Galaxy for the first time. The chemo-kinematic data dissected on an eccentricity-|Z|(max) plane reveal the chemical and kinematic signatures of the bar, the thin inner disc, and an inner thick disc, and a broad metallicity population with large velocity dispersion indicative of a pressure-supported component. The interplay between these different populations is mapped onto the different metallicity distributions seen in the eccentricity-|Z|(max) diagram consistently with the mean orbital radius and V-phi distributions. A clear metallicity gradient as a function of |Z|(max) is also found, which is consistent with the spatial overlapping of different populations. Additionally, we find and chemically and kinematically characterize a group of counter-rotating stars that could be the result of a gas-rich merger event or just the result of clumpy star formation during the earliest phases of the early disc that migrated into the bulge. Finally, based on 6D information, we assign stars a probability value of being on a bar orbit and find that most of the stars with large bar orbit probabilities come from the innermost 3 kpc, with a broad dispersion of metallicity. Even stars with a high probability of belonging to the bar show chemical bimodality in the {[}alpha/Fe] versus {[}Fe/H] diagram. This suggests bar trapping to be an efficient mechanism, explaining why stars on bar orbits do not show a significant, distinct chemical abundance ratio signature. (AU) | |
| FAPESP's process: | 17/15893-1 - Globular cluster orbits of bulge: the formation and evolution of the Milky Way |
| Grantee: | Maria de Los Angeles Perez Villegas |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |