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Two New Ultra-Faint Star Clusters in the Milky Way Halo

Published online by Cambridge University Press:  09 May 2016

Dongwon Kim
Dongwon Kim*
Affiliation:
Research School of Astronomy and Astrophysics, The Australian National University, Mt Stromlo Observatory, via Cotter Rd, Weston, ACT 2611, Australia email: [email protected]
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Abstract

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Kim 1 & 2 are two new star clusters discovered in the Stromlo Missing Satellite Survey. Kim 1, located at a heliocentric distance of 19.8 ± 0.9 kpc, features an extremely low total luminosity (MV = 0.3 ± 0.5 mag) and low star concentration. Together with the large ellipticity (ε = 0.42 ± 0.10) and irregular isophotes, these properties suggest that Kim 1 is an intermediate mass star cluster being stripped by the Galactic tidal field. Kim 2 is a rare ultra-faint outer halo globular cluster located at a heliocentric distance of 104.7 ± 4.1 kpc. The cluster exhibits evidence of significant mass loss such as extra-tidal stars and mass-segregation. Kim 2 is likely to follow an orbit confined to the peripheral region of the Galactic halo, and/or to have formed in a dwarf galaxy that was later accreted into the Galactic halo.

Keywords

Galaxyhaloglobular clustersdwarf galaxies
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 11 , Issue S317: The General Assembly of Galaxy Halos: Structure, Origin and Evolution , August 2015 , pp. 314 - 315
Copyright
Copyright © International Astronomical Union 2016 

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