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Halo K-Giant Stars from LAMOST: Kinematics and Galactic Mass Estimate

Published online by Cambridge University Press:  21 March 2017

Sarah A. Bird
Sarah A. Bird*
Affiliation:
Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 200030, China email: [email protected]
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Abstract

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We analyze line-of-sight velocities of over 3000 halo K-giant stars from the second data release of the spectral survey LAMOST (Zhao et al. 2012). We find a nearly constant velocity dispersion profile, with no large dips or peaks, in a Galactocentric radial range of 10–30 kpc, in accord with earlier analyses (Battaglia et al. 2005, 2006; Xue et al. 2008, 2014) (see Fig. 1). Previous studies of halo star radial velocity dispersions in a reference frame centered on the Galactic Center have detected dips within this radial range (Sommer-Larsen et al. 1994; Kafle et al. 2012, 2014). We use the stars to make estimates of the enclosed mass out to 40 kpc from the Galactic Center using the method of Evans et al. (2011). Tens of thousands of such stars are expected to become available to this analysis by the end of the five-year survey.

Keywords

Galaxy: halostars: individual (K giants)stars: kinematics and dynamics
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 11 , Symposium S321: Formation and Evolution of Galaxy Outskirts , March 2016 , pp. 48
Copyright
Copyright © International Astronomical Union 2017 

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