Luque, E;
Queiroz, A;
Santiago, B;
Pieres, A;
Balbinot, E;
Bechtol, K;
Drlica-Wagner, A;
... Zhang, Y; + view all
(2016)
Digging deeper into the Southern skies: a compact Milky Way companion discovered in first-year Dark Energy Survey data.
Monthly Notices of the Royal Astronomical Society
, 458
(1)
pp. 603-612.
10.1093/mnras/stw302.
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Abstract
We use the first-year Dark Energy Survey (DES) data down to previously unprobed photometric depths to search for stellar systems in the Galactic halo, therefore complementing the previous analysis of the same data carried out by our group earlier this year. Our search is based on a matched filter algorithm that produces stellar density maps consistent with stellar population models of various ages, metallicities, and distances over the survey area. The most conspicuous density peaks in these maps have been identified automatically and ranked according to their significance and recurrence for different input models. We report the discovery of one additional stellar system besides those previously found by several authors using the same first-year DES data. The object is compact, and consistent with being dominated by an old and metal-poor population. DES 1 is found at high significance and appears in the DES images as a compact concentration of faint blue point sources. Assuming different spatial profile parameterizations, the best-fitting heliocentric distance and total absolute magnitude in the range of 77.6–87.1 kpc and −3.00 ≲ MV ≲ −2.21, respectively. The half-light radius of this object, rh ∼ 10 pc and total luminosity are consistent with it being a low-mass halo cluster. It is also found to have a very elongated shape (ϵ ∼ 0.57). In addition, our deeper probe of DES first-year data confirms the recently reported satellite galaxy candidate Horologium II as a significant stellar overdensity. We also infer its structural properties and compare them to those reported in the literature.
| Type: | Article |
|---|---|
| Title: | Digging deeper into the Southern skies: a compact Milky Way companion discovered in first-year Dark Energy Survey data |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stw302 |
| Publisher version: | http://dx.doi.org/10.1093/mnras/stw302 |
| Additional information: | © 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society |
| Keywords: | globular clusters: general, globular clusters: individual (DES 1), galaxies: dwarf |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1541737 |
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