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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 276741.0, MPI für Astronomie / Publikationen_mpia
The dwarf galaxy DDO 47 as a dark matter laboratory: Testing cusps hiding in triaxial halos
Authors:Gentile, G.; Burkert, A.; Salucci, P.; Klein, U.; Walter, F.
Date of Publication (YYYY-MM-DD):2005
Title of Journal:The Astrophysical Journal
Journal Abbrev.:The Astrophysical Journal
Start Page:L145
End Page:L148
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:We present an analysis of high-resolution H I data of the dwarf galaxy DDO 47, aimed at testing the hypothesis that dark halo triaxiality might induce noncircular motions resulting in rotation curves best fitted by cored halos, even if the dark matter halo is intrinsically cuspy. This hypothesis could be invoked in order to reconcile the predictions of the standard LambdaCDM theory with the rotation curves of disk galaxies. DDO 47 is an ideal case to test this hypothesis because it has a very regular velocity field, its rotation curve is best fitted by a cored halo, and an NFW halo is inconsistent with the data. We analyze the velocity field through the higher order harmonic terms in order to search for kinematical signatures of alleged noncircular motions needed to ``hide'' a cusp: the result is that globally noncircular motions are at a level of 2-3 km s-1, and they are more likely to be associated with the presence of some spiral structure than with a global elongated potential (e.g., a triaxial halo). These noncircular motions are far from being sufficient to account for the discrepancy with the LambdaCDM predictions. We therefore conclude that the dark matter halo around the dwarf galaxy DDO 47 is truly cored and that a cusp cannot be hidden by noncircular motions.
Free Keywords:Cosmology: Dark Matter; Galaxies: Dwarf; galaxies: individual (DDO 47); Galaxies: Kinematics and Dynamics
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/cgi-bin/nph- bib_query?b... [ID No:1]
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