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A RADIAL VELOCITY AND CALCIUM TRIPLET ABUNDANCE SURVEY OF FIELD SMALL MAGELLANIC CLOUD GIANTS
被引:25
|作者:
De Propris, Roberto
[1
]
Rich, R. Michael
[2
]
Mallery, Ryan C.
[2
]
Howard, Christian D.
[3
]
机构:
[1] Cerro Tololo Interamer Observ, La Serena, Chile
[2] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA USA
[3] NASA, Ames Res Ctr, SOFIA USRA, Moffett Field, CA 94035 USA
基金:
美国国家航空航天局;
美国国家科学基金会;
关键词:
galaxies: stellar content;
Magellanic Clouds;
DWARF SPHEROIDAL GALAXY;
INFRARED CAII TRIPLET;
EMPIRICAL CALIBRATION;
STELLAR POPULATIONS;
ROTATION CURVE;
PROPER MOTION;
STAR-CLUSTERS;
OUTER EDGE;
MILKY-WAY;
KINEMATICS;
D O I:
10.1088/2041-8205/714/2/L249
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
We present the results of a pilot wide-field radial velocity and metal abundance survey of red giants in 10 fields in the Small Magellanic Cloud (SMC). The targets lie at projected distances of 0.9 and 1.9 kpc from the SMC center (m - M = 18.79) to the north, east, south, and west. Two more fields are to the east at distances of 3.9 and 5.1 kpc. In this last field, we find only a few to no SMC giants, suggesting that the edge of the SMC in this direction lies approximately at 6 kpc from its center. In all eastern fields, we observe a double peak in the radial velocities of stars, with a component at the classical SMC recession velocity of similar to 160 km s(-1) and a high-velocity component at about 200 km s(-1), similar to observations in Hi. In the most distant field (3.9 kpc), the low-velocity component is at 106 km s(-1). The metal abundance distribution in all fields is broad and centered at about [Fe/H] similar to -1.25, reaching to solar and possibly slightly supersolar values and down to [Fe/H] of about -2.5. In the two innermost (0.9 kpc) northern and southern fields, we observe a secondary peak at metallicities of about similar to -0.6. This may be evidence of a second episode of star formation in the center, possibly triggered by the interactions that created the Stream and Bridge.
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页码:L249 / L253
页数:5
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