期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 468, 期 1, 页码 97-108出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stx405
关键词
globular clusters: general; galaxies: dwarf
资金
- US Department of Energy
- US National Science Foundation
- Ministry of Science and Education of Spain
- Science and Technology Facilities Council of the United Kingdom
- Higher Education Funding Council for England
- NationalCenter for Supercomputing Applications at the University of Illinois at UrbanaChampaign
- Kavli Institute of Cosmological Physics at the University of Chicago
- Center for Cosmology and Astro-Particle Physics at the Ohio State University
- Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University
- Financiadora de Estudos e Projetos
- Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro
- Conselho Nacional de Desenvolvimento Cientifico e Tecnologico
- Ministerio da Ciencia, Tecnologia e Inovacao
- Deutsche Forschungsgemeinschaft
- Collaborating Institutions in the DES
- National Science Foundation [AST-1138766]
- MINECO [AST-1138766, AYA2012-39559, ESP2013-48274, FPA2013-47986, ESP201348274]
- Centro de Excelencia Severo Ochoa [SEV-2012-0234]
- European Union
- European Research Council under the European Union's Seventh Framework Programme (FP7) including ERC [240672, 291329, 306478]
- European Research Council (CLUSTERS) [ERC-StG-335936]
- ICREA Funding Source: Custom
- Direct For Mathematical & Physical Scien
- Division Of Physics [1125897] Funding Source: National Science Foundation
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1311924] Funding Source: National Science Foundation
- STFC [ST/H001581/1, ST/M001334/1, ST/N001087/1, ST/L006529/1, ST/P000525/1, ST/L000652/1, ST/M003574/1, ST/I000976/1] Funding Source: UKRI
We report the discovery of two new candidate stellar systems in the constellation of Cetus using the data from the first two years of the Dark E nergy Survey (DES). The objects, DES J0111-1341 and DES J0225+ 0304, are located at a heliocentric distance of -25 kpc and appear to have old and metal-poor populations. Their distances to the Sagittarius orbital plane, -1.73 kpc (DES J0111-1341) and -0.50 kpc (DES J0225+ 0304), indicate that they are possibly associated with the Sagittarius dwarf stream. The half-light radius (r(h) similar or equal to 4.55 pc) and luminosity (MV similar or equal to + 0.3) of DES J0111-1341 are consistent with it being an ultrafaint stellar cluster, while the half-light radius (rh similar or equal to 18.55 pc) and luminosity (MV similar or equal to -1.1) of DES J0225+ 0304 place it in an ambiguous region of size-luminosity space between stellar clusters and dwarf galaxies. Determinations of the characteristic parameters of the Sagittarius stream, metallicity spread (-2.18 <= [ Fe/ H] <= -0.95) and distance gradient (23 kpc <= D-circle dot <= 29 kpc), within the DES footprint in the Southern hemisphere, using the same DES data, also indicate a possible association between these systems. If these objects are confirmed through spectroscopic follow-up to be gravitationally bound systems and to share a Galactic trajectory with the Sagittarius stream, DES J0111-1341 and DES J0225+ 0304 would be the first ultrafaint stellar systems associated with the Sagittarius stream. Furthermore, DES J0225+ 0304 would also be the first confirmed case of an ultrafaint satellite of a satellite.
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