Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-12-15
Astronomy and Astrophysics
Astrophysics
Accepted for publication in AJ; 54 pages, 14 figures (3 color), 5 tables
Scientific paper
10.1086/428007
We report metallicities and radial velocities derived from spectra at the near-infrared calcium triplet for 373 red giants in a 200 square arcminute area at the optical center of the LMC bar. These are the first spectroscopic abundance measurements of intermediate-age and old field stars in the high surface brightness heart of the LMC. The metallicity distribution is sharply peaked at the median value [Fe/H] = -0.40, with a small tail of stars extending down to [Fe/H] <= -2.1; 10% of the red giants are observed to have [Fe/H] <= -0.7. The relative lack of metal-poor stars indicates that the LMC has a "G dwarf" problem, similar to the Milky Way. The abundance distribution can be closely approximated by two Gaussians containing 89% and 11% of the stars, respectively: the first component is centered at [Fe/H] = -0.37 with standard deviation = 0.15, and the second at [Fe/H] = -1.08 with standard deviation = 0.46. Because of the central location of our field, kinematic constraints are not strong, but there is no evidence that the bar deviates from the general motion of the LMC disk. The velocity dispersion of the whole sample is 24.7 +/- 0.4 km/sec. The most metal-poor 5% of stars ([Fe/H] < -1.15) show a dispersion of 40.8 +/- 1.7 km/sec, more than twice the value for the most metal-rich 5%. The age-metallicity relation (AMR) is almost flat during the period from 5-10 Gyr ago, with an apparent scatter of +/-0.15 dex about the mean metallicity for a given age. (abstract abridged)
Cole Andrew A.
Gallagher III S. . J.
Smecker-Hane Tammy Ann
Tolstoy Eline
No associations
LandOfFree
Spectroscopy of Red Giants in the LMC Bar: Abundances, Kinematics, and the Age-Metallicity Relation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Spectroscopy of Red Giants in the LMC Bar: Abundances, Kinematics, and the Age-Metallicity Relation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectroscopy of Red Giants in the LMC Bar: Abundances, Kinematics, and the Age-Metallicity Relation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-627785