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Density variations in the NW star stream of M31

Carlberg, R G; Richer, Harvey B; McConnachie, Alan W; Irwin, M. J.; Ibata, Rodrigo A; Dotter, Aaron; Chapman, S. C.; Fardal, Mark; Ferguson, A. M. N.; Lewis, Geraint Francis; Navarro, J F; Puzia, Thomas H; Valls-Gabuad, David

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The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of...[Show more]

dc.contributor.authorCarlberg, R G
dc.contributor.authorRicher, Harvey B
dc.contributor.authorMcConnachie, Alan W
dc.contributor.authorIrwin, M. J.
dc.contributor.authorIbata, Rodrigo A
dc.contributor.authorDotter, Aaron
dc.contributor.authorChapman, S. C.
dc.contributor.authorFardal, Mark
dc.contributor.authorFerguson, A. M. N.
dc.contributor.authorLewis, Geraint Francis
dc.contributor.authorNavarro, J F
dc.contributor.authorPuzia, Thomas H
dc.contributor.authorValls-Gabuad, David
dc.date.accessioned2015-12-13T22:41:39Z
dc.identifier.issn0004-637X
dc.identifier.urihttp://hdl.handle.net/1885/78597
dc.description.abstractThe Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2-20 kpc. The probability that the variations are random fluctuations in the star density is less than 10-5. As a control sample, we search for density variations at precisely the same location in stars with metallicity higher than the stream [Fe/H] = [0, -0.5] and find no variations above the expected shot noise. The lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential, nor is it readily compatible with the disturbance caused by the visible M31 satellite galaxies. The stream's density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub-halos, such as found in LCDM simulations, acting on an approximately 10 Gyr old star stream. The effects of a single set of halo substructure realizations are shown for illustration, reserving a statistical comparison for another study.
dc.publisherIOP Publishing
dc.sourceAstrophysical Journal, The
dc.subjectKeywords: dark matter; galaxies: dwarf; Local Group
dc.titleDensity variations in the NW star stream of M31
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume731
dc.date.issued2011
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.ariespublicationf5625xPUB7215
local.type.statusPublished Version
local.contributor.affiliationCarlberg, R G, University of Toronto
local.contributor.affiliationRicher, Harvey B, University of British Columbia
local.contributor.affiliationMcConnachie, Alan W, NRC Herzberg Institute of Astrophysics
local.contributor.affiliationIrwin, M. J., University of Cambridge
local.contributor.affiliationIbata, Rodrigo A, Universite de Strasbourg
local.contributor.affiliationDotter, Aaron, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationChapman, S. C., University of Cambridge
local.contributor.affiliationFardal, Mark, University of Massachusetts
local.contributor.affiliationFerguson, A. M. N., University of Edinburgh
local.contributor.affiliationLewis, Geraint Francis, University of Sydney
local.contributor.affiliationNavarro, J F, University of Victoria
local.contributor.affiliationPuzia, Thomas H, Pontificia Universidade Catlica de Chile
local.contributor.affiliationValls-Gabuad, David, Observatoire de Paris
local.description.embargo2037-12-31
local.bibliographicCitation.issue2
local.bibliographicCitation.startpage124
local.identifier.doi10.1088/0004-637X/731/2/124
dc.date.updated2016-02-24T09:33:34Z
local.identifier.scopusID2-s2.0-79955052945
CollectionsANU Research Publications

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