10-1093-MNRAS-STW302.pdf (4.21 MB)
Digging deeper into the Southern skies: a compact Milky Way companion discovered in first-year Dark Energy Survey data
journal contribution
posted on 2023-06-09, 01:06 authored by E Luque, A Queiroz, B Santiago, A Pieres, E Balbinot, K Bechtol, A Drlica-Wagner, A Fausti Neto, L N da Costa, M A G Maia, B Yanny, T Abbott, S Allam, A Benoit-Lévy, E Bertin, D Brooks, E Buckley-Geer, D L Burke, A Carnero Rosell, M Carrasco Kind, J Carretero, C E Cunha, S Desai, H T Diehl, J P Dietrich, T F Eifler, D A Finley, B Flaugher, P Fosalba, J Frieman, D W Gerdes, D Gruen, G Gutierrez, K Honscheid, D J James, K Kuehn, N Kuropatkin, O Lahav, T S Li, M March, J L Marshall, P Martini, R Miquel, E Neilsen, R C Nichol, B Nord, R Ogando, A A Plazas, Kathy RomerKathy Romer, A Roodman, E Sanchez, V Scarpine, M Schubnell, I Sevilla-Noarbe, R C Smith, M Soares-Santos, F Sobreira, E Suchyta, M E C Swanson, G Tarle, J Thaler, D Tucker, A R Walker, Y ZhangWe 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 (e ˜ 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.
Funding
Astrophysics and Cosmology - Sussex Consolidated Grant; G1291; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/L000652/1
History
Publication status
- Published
File Version
- Published version
Journal
Monthly Notices of the Royal Astronomical SocietyISSN
0035-8711Publisher
Oxford University PressExternal DOI
Issue
1Volume
458Page range
603-612Department affiliated with
- Physics and Astronomy Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2016-05-05First Open Access (FOA) Date
2016-05-05First Compliant Deposit (FCD) Date
2016-05-05Usage metrics
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