2017A&A...605A..89B


Query : 2017A&A...605A..89B

2017A&A...605A..89B - Astronomy and Astrophysics, volume 605A, 89-89 (2017/9-1)

Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VI. Age and abundance structure of the stellar populations in the central sub-kpc of the Milky Way.

BENSBY T., FELTZING S., GOULD A., YEE J.C., JOHNSON J.A., ASPLUND M., MELENDEZ J., LUCATELLO S., HOWES L.M., McWILLIAM A., UDALSKI A., SZYMANSKI M.K., SOSZYNSKI I., POLESKI R., WYRZYKOWSKI L., ULACZYK K., KOZLOWSKI S., PIETRUKOWICZ P., SKOWRON J., MROZ P., PAWLAK M., ABE F., ASAKURA Y., BHATTACHARYA A., BOND I.A., BENNETT D.P., HIRAO Y., NAGAKANE M., KOSHIMOTO N., SUMI T., SUZUKI D. and TRISTRAM P.J.

Abstract (from CDS):

We present a detailed elemental abundance study of 90 F and G dwarf, turn-off, and subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages and abundances for 11 elements (Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Zn, Y and Ba) have been determined. Four main findings are presented: (1) a wide metallicity distribution with distinct peaks at [Fe/H]=-1.09, -0.63, -0.20, + 0.12, + 0.41; (2) a highfraction of intermediate-age to young stars where at [Fe/H]>0 more than 35% are younger than 8Gyr, and for [Fe/H]≤-0.5 most stars are 10Gyr or older; (3) several episodes of significant star formation in the bulge has been identified: 3, 6, 8, and 11Gyr ago; (4) tentatively the "knee" in the α-element abundance trends of the sub-solar metallicity bulge is located at a slightly higher [Fe/H] than in the local thick disk. These findings show that the Galactic bulge has complex age and abundance properties that appear to be tightly connected to the main Galactic stellar populations. In particular, the peaks in the metallicity distribution, the star formation episodes, and the abundance trends, show similarities with the properties of the Galactic thin and thick disks. At the same time, the star formation rate appears to have been slightly faster in the bulge than in the local thick disk, which most likely is an indication of the denser stellar environment closer to the Galactic centre. There are also additional components not seen outside the bulge region, and that most likely can be associated with the Galactic bar. Our results strengthen the observational evidence that support the idea of a secular origin for the Galactic bulge, formed out of the other main Galactic stellar populations present in the central regions of our Galaxy. Additionally, our analysis of this enlarged sample suggests that the (V-I)0 colour of the bulge red clump should be revised to 1.09.

Abstract Copyright: © ESO, 2017

Journal keyword(s): gravitational lensing: micro - Galaxy: bulge - Galaxy: formation - Galaxy: evolution - stars: abundances - stars: abundances

VizieR on-line data: <Available at CDS (J/A+A/605/A89): tablea2.dat tablea1.dat>

Simbad objects: 91

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Number of rows : 91
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 EWS 2012-BLG-270 * 17 14 42.460 -29 35 50.40           ~ 4 0
2 OGLE BLG613.8 68613 * 17 32 49.61 -29 23 10.6           ~ 5 0
3 EWS 2012-BLG-26 * 17 34 18.6971878685 -27 08 33.945761867           ~ 32 1
4 OGLE BLG604.24 29952 * 17 43 38.53 -35 05 12.1           ~ 3 0
5 OGLE BLG603.5 113678 * 17 45 00.65 -34 32 49.5           ~ 6 0
6 OGLE BLG660.5 81711 * 17 45 13.37 -33 29 50.4           ~ 3 0
7 EWS 2013-BLG-1938 * 17 46 01.890 -34 12 31.50           ~ 2 0
8 MOA 2009-BLG-456 * 17 48 56.40 -34 13 29.7           ~ 6 0
9 MOA 2011-BLG-191 * 17 51 40.150 -29 53 26.15           ~ 4 0
10 MOA 2010-BLG-78 * 17 52 01.650 -30 24 25.63           ~ 5 0
11 EWS 2013-BLG-1768 * 17 52 26.580 -31 36 43.80           ~ 2 0
12 OGLE BLG503.10 121377 * 17 52 48.18 -35 00 51.4           ~ 3 0
13 EWS 2013-BLG-835 * 17 52 59.390 -29 05 57.10           ~ 2 0
14 EWS 2013-BLG-1125 * 17 53 27.010 -29 47 34.10           ~ 2 0
15 OGLE BLG535.9 35861 * 17 54 02.42 -32 35 31.6           ~ 3 0
16 EWS 2013-BLG-1793 * 17 54 04.690 -29 38 04.10           ~ 2 0
17 MOA 2006-BUL-99 * 17 54 10.99 -35 13 38.0           G 13 0
18 NAME OGLE 2011-BLG-012N * 17 54 11.320 -30 05 21.56           ~ 5 0
19 MOA 2008-BLG-310 * 17 54 14.53 -34 46 41.0           GV 44 1
20 MOA 2013-BLG-68 * 17 54 21.860 -31 11 39.95           ~ 2 0
21 MOA 2011-BLG-104 * 17 54 22.480 -29 50 01.67           ~ 10 0
22 EWS 2013-BLG-1114 * 17 54 24.400 -28 56 32.10           ~ 2 0
23 OGLE BLG507.25 76512 * 17 54 48.34 -31 25 57.8           ~ 5 0
24 EWS 2012-BLG-617 * 17 54 53.870 -31 08 19.10           ~ 5 0
25 EWS 2015-BLG-78 * 17 55 30.690 -27 57 36.50           ~ 2 0
26 MOA 2013-BLG-551 * 17 55 31.980 -29 15 13.80           ~ 6 0
27 OGLE BLG507.14 156979 * 17 55 42.33 -31 53 34.3           ~ 3 0
28 MOA 2009-BLG-493 * 17 55 46.13 -28 48 25.5           ~ 7 0
29 OGLE BLG507.31 100807 * 17 55 59.48 -31 16 35.8           ~ 3 0
30 EWS 2014-BLG-1469 * 17 56 07.540 -30 57 13.00           ~ 2 0
31 MOA 2010-BLG-285 * 17 56 48.160 -30 00 39.47           ~ 6 0
32 OGLE BLG507.13 70237 * 17 56 52.39 -31 46 54.5           ~ 5 0
33 MOA 2008-BLG-311 * 17 56 53.65 -31 23 49.9           ~ 15 0
34 EWS 2011-BLG-1072 * 17 56 53.940 -28 50 53.31           ~ 4 0
35 MOA 2010-BLG-523 RS* 17 57 08.870 -29 44 58.40           ~ 10 0
36 MOA 2011-BLG-336 * 17 57 16.620 -32 39 57.15           ~ 8 0
37 MOA 2011-BLG-174 * 17 57 20.620 -30 22 47.57           ~ 4 0
38 MOA 2012-BLG-22 * 17 57 40.970 -27 29 56.49           ~ 4 0
39 MOA 2009-BLG-489 * 17 57 46.67 -28 38 56.9           ~ 7 0
40 MOA 2009-BLG-259 * 17 57 57.51 -29 11 39.4           ~ 7 0
41 EWS 2007-BUL-514 * 17 58 03.09 -27 31 05.7           ~ 13 0
42 EWS 2012-BLG-816 * 17 58 15.980 -29 57 21.45           ~ 4 0
43 OGLE BLG509.28 42093 * 17 58 16.85 -33 46 18.8           ~ 3 0
44 EWS 2009-BLG-76 * 17 58 31.93 -29 12 17.9           ~ 11 0
45 MOA 2012-BLG-532 * 17 58 41.130 -30 02 11.80           ~ 6 0
46 MOA 2013-BLG-605 * 17 58 42.880 -29 23 53.60           ~ 13 0
47 OGLE BLG507.19 119151 * 17 58 56.67 -31 26 31.1           ~ 5 0
48 MOA 2014-BLG-131 * 17 59 02.500 -31 01 54.70           ~ 2 0
49 EWS 2012-BLG-1156 * 18 00 35.950 -28 11 15.20           ~ 4 0
50 EWS 2012-BLG-1534 * 18 00 46.350 -28 01 00.30           ~ 4 0
51 MOA 2009-BLG-174 * 18 02 07.70 -31 25 26.4           FV 8 0
52 MOA 2009-BLG-475 * 18 02 27.46 -27 26 49.4           ~ 7 0
53 OGLE BLG516.30 79355 * 18 02 29.58 -33 06 32.0           ~ 3 0
54 MOA 2012-BLG-291 * 18 02 43.080 -28 23 00.86           ~ 5 0
55 MOA 2013-BLG-402 * 18 03 00.140 -29 54 24.42           ~ 3 0
56 MOA 2011-BLG-445 * 18 04 45.630 -28 35 44.06           ~ 4 0
57 EWS 2008-BUL-209 * 18 04 49.84 -29 42 33.2           ~ 12 0
58 OGLE BUL-SC33 164492 * 18 05 05.28 -28 34 41.7           ~ 32 0
59 MOA 2010-BLG-49 * 18 05 07.020 -26 46 12.79           ~ 5 0
60 MOA 2010-BLG-37 * 18 05 17.930 -27 56 13.21           ~ 5 0
61 MOA 2007-BLG-379 ** 18 05 24.43 -26 25 18.8           ~ 38 1
62 EWS 2013-BLG-1868 * 18 05 35.560 -30 53 06.50           ~ 2 0
63 EWS 2012-BLG-521 * 18 05 36.740 -25 45 47.42           ~ 4 0
64 OGLE BLG513.17 85619 * 18 05 55.57 -29 40 56.3           ~ 3 0
65 MOA 2012-BLG-288 * 18 05 57.720 -27 42 43.20           ~ 10 0
66 MOA 2009-BLG-133 * 18 06 32.85 -31 30 11.4           ~ 7 0
67 EWS 2013-BLG-446 * 18 06 56.180 -31 39 27.20           ~ 4 0
68 OGLE BLG519.14 123254 * 18 07 04.26 -28 03 57.9           ~ 6 0
69 EWS 2006-BUL-265 * 18 07 18.88 -27 47 42.7           G 15 0
70 OGLE BLG519.22 117841 * 18 07 43.23 -27 48 50.1           ~ 3 0
71 OGLE BLG520.13 53669 * 18 08 02.17 -29 28 11.3           ~ 5 0
72 OGLE BLG518.21 8862 * 18 08 39.19 -26 40 44.8           ~ 3 0
73 MOA 2010-BLG-311 * 18 08 49.980 -25 57 04.27           ~ 10 0
74 OGLE BLG518.3 140178 * 18 08 52.98 -27 16 04.1           ~ 3 0
75 OGLE BLG520.11 172127 * 18 09 00.33 -29 14 12.7           ~ 6 0
76 OGLE BLG573.28 60514 * 18 09 41.13 -31 11 04.7           ~ 5 0
77 EWS 2012-BLG-1526 * 18 09 43.130 -28 48 45.20           ~ 4 0
78 EWS 2012-BLG-211 * 18 10 10.960 -25 01 40.20           ~ 5 0
79 MOA 2011-BLG-34 * 18 10 12.230 -27 32 02.39           ~ 6 0
80 OGLE BLG519.26 139638 * 18 10 16.85 -27 37 59.0           ~ 5 0
81 MOA 2012-BLG-410 * 18 10 22.620 -25 10 16.83           ~ 4 0
82 EWS 2013-BLG-1259 * 18 10 23.340 -27 58 45.60           ~ 2 0
83 MOA 2011-BLG-90 * 18 10 29.850 -26 38 43.03           ~ 8 0
84 OGLE BLG518.17 141255 * 18 10 56.83 -26 33 48.5           ~ 5 0
85 OGLE BLG545.16 79421 * 18 10 56.92 -25 01 38.3           ~ 3 0
86 OGLE BLG525.25 58563 * 18 11 27.40 -29 41 02.8           ~ 6 0
87 MOA 2012-BLG-202 * 18 12 34.840 -25 02 59.79           ~ 4 0
88 MOA 2013-BLG-517 * 18 13 36.420 -27 43 22.83           ~ 2 0
89 OGLE BLG522.11 4130 * 18 14 47.62 -26 24 38.9           ~ 3 0
90 OGLE BLG523.18 72530 * 18 16 06.66 -27 11 06.0           ~ 3 0
91 OGLE BLG529.24 95835 * 18 16 53.61 -25 31 31.0           ~ 3 0

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2021.09.21-09:53:43

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