THE MASSES OF LOCAL GROUP DWARF SPHEROIDAL GALAXIES: THE DEATH OF THE UNIVERSAL MASS PROFILE

Michelle L. M. Collins*, Scott C. Chapman, R. M. Rich, Rodrigo A. Ibata, Nicolas F. Martin, Michael J. Irwin, Nicholas F. Bate, Geraint F. Lewis, Jorge Penarrubia, Nobuo Arimoto, Caitlin M. Casey, Annette M. N. Ferguson, Andreas Koch, Alan W. McConnachie, Nial Tanvir

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the claim that all dwarf spheroidal galaxies (dSphs) reside within halos that share a common, universal mass profile as has been derived for dSphs of the galaxy. By folding in kinematic information for 25 Andromeda dSphs, more than doubling the previous sample size, we find that a singular mass profile cannot be found to fit all of the observations well. Further, the best-fit dark matter density profile measured solely for the Milky Way dSphs is marginally discrepant with that of the Andromeda dSphs (at just beyond the 1 sigma level), where a profile with lower maximum circular velocity, and hence mass, is preferred. The agreement is significantly better when three extreme Andromeda outliers, And XIX, XXI, and XXV, all of which have large half-light radii (greater than or similar to 600 pc) and low-velocity dispersions (sigma(v) <5 k ms(-1)), are omitted from the sample. We argue that the unusual properties of these outliers are likely caused by tidal interactions with the host galaxy.

Original languageEnglish
Article number7
Number of pages14
JournalAstrophysical Journal
Volume783
Issue number1
DOIs
Publication statusPublished - 1 Mar 2014

Keywords

  • dark matter
  • galaxies: dwarf
  • galaxies: fundamental parameters
  • galaxies: kinematics and dynamics
  • Local Group
  • DARK-MATTER HALOS
  • MILKY-WAY HALO
  • MISSING-SATELLITES PROBLEM
  • M31 SATELLITES
  • OCCUPATION DISTRIBUTION
  • STELLAR KINEMATICS
  • BRIGHT SATELLITES
  • DENSITY PROFILES
  • ROTATION CURVES
  • STAR-FORMATION

Fingerprint

Dive into the research topics of 'THE MASSES OF LOCAL GROUP DWARF SPHEROIDAL GALAXIES: THE DEATH OF THE UNIVERSAL MASS PROFILE'. Together they form a unique fingerprint.

Cite this