A survey for dwarf galaxy remnants around 14 globular clusters in the outer halo
Abstract
We report the results of a systematic photometric survey of the peripheral regions of a sample of 14 globular clusters in the outer halo of the Milky Way at distances dGC > 25 kpc from the Galactic Centre. The survey is aimed at searching for the remnants of the host satellite galaxies where these clusters could originally have been formed before being accreted on to the Galactic halo. The limiting surface brightness varies within our sample, but reaches μV, lim = 30-32 mag arcsec-2. For only two globular clusters (NGC 7492 and Whiting 1; already suggested to be associated with the Sagittarius galaxy), we detect extended stellar populations that cannot be associated with either the clusters themselves or with the surrounding Galactic field population. We show that the lack of substructures around globular clusters at these Galactocentric distances is still compatible with the predictions of cosmological simulations whereby in the outer halo the Galactic globular cluster system is built up through hierarchical accretion at early epochs.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2018
- DOI:
- 10.1093/mnras/sty539
- arXiv:
- arXiv:1802.09255
- Bibcode:
- 2018MNRAS.476.4814S
- Keywords:
-
- methods: observational;
- techniques: photometric;
- stars: Population II;
- globular clusters: general;
- Galaxy: halo;
- Galaxy: structure;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 18 pages, 10 figures, accepted for publication by MNRAS