The Masses of Local Group Dwarf Spheroidal Galaxies: the Death of the Universal Mass Profile
Year: 2014
Type: article
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 1σ 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 (≳ 600 pc) and low-velocity dispersions (σ v < 5 km s −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.
Source: The Astrophysical Journal
Authors: 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 Peñarrubia, Nobuo Arimoto, Caitlin M. Casey, Annette M. N. Ferguson, Andreas Koch, Alan W. McConnachie, Nial Tanvir
Institutions: Max Planck Institute for Astronomy, Dalhousie University, University of Cambridge, University of California, Los Angeles, Observatoire astronomique de Strasbourg, The University of Sydney, Instituto de Astrofísica de Andalucía, The Graduate University for Advanced Studies, SOKENDAI, National Astronomical Observatory of Japan, Royal Observatory, University of Edinburgh, Heidelberg University, Herzberg Institute of Astrophysics, University of Leicester
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: Cambridge Astronomical Survey Unit Project Portfolio, G2845385625, Galaxy formation and evolution 2010 - 2015, Pixel Observations of M31 and M33 with MEgacam, PATT-linked grant for IoA 2013-2015, A Consolidated Grant Proposal for Astrophysics and Solar System Research at the University of Leicester, 2013-2016, Gamma-Ray Bursts: their Nature and use as Cosmological Probes
OpenAlex ID: W2054753318