Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Evidence for substructure in Ursa Minor dwarf spheroidal galaxy using a Bayesian object detection method
Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC). University of California Irvine, USA.
2014 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 442, no 2, 1718-1730 p.Article in journal (Refereed) Published
Abstract [en]

We present a method for identifying localized secondary populations in stellar velocity data using Bayesian statistical techniques. We apply this method to the dwarf spheroidal galaxy Ursa Minor and find two secondary objects in this satellite of the Milky Way. One object is kinematically cold with a velocity dispersion of 4.25 +/- A 0.75 km s(-1) and centred at (9.1 arcmin +/- 1.5, 7.2 arcmin +/- 1.2) in relative RA and Dec. with respect to the centre of Ursa Minor. The second object has a large velocity offset of -12.8(-1.5)(+1.75) km s(-1) compared to Ursa Minor and centred at (-14.0 arcmin(-5.8)(+2.4), -2.5 arcmin(-1.0)(+0.4)). The kinematically cold object has been found before using a smaller data set, but the prediction that this cold object has a velocity dispersion larger than 2.0 km s(-1) at 95 per cent confidence level differs from previous work. We use two- and three-component models along with the information criteria and Bayesian evidence model selection methods to argue that Ursa Minor has additional localized secondary populations. The significant probability for a large velocity dispersion in each secondary object raises the intriguing possibility that each has its own dark matter halo, that is, it is a satellite of a satellite of the Milky Way.

Place, publisher, year, edition, pages
2014. Vol. 442, no 2, 1718-1730 p.
Keyword [en]
methods: statistical, galaxies: kinematics and dynamics, Local Group
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:su:diva-107030DOI: 10.1093/mnras/stu938ISI: 000339423100062OAI: oai:DiVA.org:su-107030DiVA: diva2:743594
Note

AuthorCount:4;

Available from: 2014-09-04 Created: 2014-09-02 Last updated: 2017-12-05Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Department of PhysicsThe Oskar Klein Centre for Cosmo Particle Physics (OKC)
In the same journal
Monthly notices of the Royal Astronomical Society
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 18 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf