期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 460, 期 1, 页码 30-43出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stw949
关键词
galaxies: dwarf; galaxies: evolution; galaxies: fundamental parameters; galaxies: individual: Sextans
资金
- Australian Postgraduate Award [DP120100475, DP150100862, DP1093431, DP120101237, DP150103294]
- U.S. Department of Energy
- National Science Foundation
- Ministry of Education and Science (Spain)
- Science and Technology Facilities Council (UK)
- Higher Education Funding Council (England)
- National Center for Supercomputing Applications
- Kavli Institute for Cosmological Physics
- Financiadora de Estudos e Projetos
- Fundacao Carlos Chagas Filho de Amparo a Pesquisa
- Conselho Nacional de Desenvolvimento Cientfico e Tecnolgico
- Ministrio da Cincia e Tecnologia (Brazil)
- German Research Foundation
- DES collaborating institutions
We present wide-field g- and i-band stellar photometry of the Sextans dwarf spheroidal galaxy and its surrounding area out to four times its half-light radius r(h) = 695 pc), based on images obtained with the Dark Energy Camera at the 4-m Blanco telescope at CTIO. We find clear evidence of stellar substructure associated with the galaxy, extending to a distance of 82 arcmin (2 kpc) from its centre. We perform a statistical analysis of the overdensities and find three distinct features, as well as an extended halo-like structure, to be significant at the 99.7 per cent confidence level or higher. Unlike the extremely elongated and extended substructures surrounding the Hercules dwarf spheroidal galaxy, the overdensities seen around Sextans are distributed evenly about its centre, and do not appear to form noticeable tidal tails. Fitting a King model to the radial distribution of Sextans stars yields a tidal radius r(t) = 83.2 arcmin +/- 7.1 arcmin (2.08 +/- 0.18 kpc), which implies the majority of detected substructure is gravitationally bound to the galaxy. This finding suggests that Sextans is not undergoing significant tidal disruption from the Milky Way, supporting the scenario in which the orbit of Sextans has a low eccentricity.
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