Dwarf Galaxy Dark Matter Density Profiles Inferred From Stellar And Gas Kinematics

dc.contributor.utaustinauthorBarentine, John C.en_US
dc.contributor.utaustinauthorGebhardt, Karlen_US
dc.contributor.utaustinauthorHill, Gary J.en_US
dc.creatorAdams, Joshua J.en_US
dc.creatorSimon, Joshua D.en_US
dc.creatorFabricius, Maximilian H.en_US
dc.creatorvan den Bosch, Remco C. E.en_US
dc.creatorBarentine, John C.en_US
dc.creatorBender, Ralfen_US
dc.creatorGebhardt, Karlen_US
dc.creatorHill, Gary J.en_US
dc.creatorMurphy, Jeremy D.en_US
dc.creatorSwaters, R. A.en_US
dc.creatorThomas, Jensen_US
dc.creatorvan de Ven, Glennen_US
dc.description.abstractWe present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low-mass galaxies frequently suggest that they contain constant density DM cores, while N-body simulations instead predict a cuspy profile. We present a data set of high-resolution integral-field spectroscopy on seven galaxies and measure the stellar and gas kinematics simultaneously. Using Jeans modeling on our full sample, we examine whether gas kinematics in general produce shallower density profiles than are derived from the stars. Although two of the seven galaxies show some localized differences in their rotation curves between the two tracers, estimates of the central logarithmic slope of the DM density profile, gamma, are generally robust. The mean and standard deviation of the logarithmic slope for the population are gamma = 0.67 +/- 0.10 when measured in the stars and gamma = 0.58 +/- 0.24 when measured in the gas. We also find that the halos are not under-concentrated at the radii of half their maximum velocities. Finally, we search for correlations of the DM density profile with stellar velocity anisotropy and other baryonic properties. Two popular mechanisms to explain cored DM halos are an exotic DM component or feedback models that strongly couple the energy of supernovae into repeatedly driving out gas and dynamically heating the DM halos. While such models do not yet have falsifiable predictions that we can measure, we investigate correlations that may eventually be used to test models. We do not find a secondary parameter that strongly correlates with the central DM density slope, but we do find some weak correlations. The central DM density slope weakly correlates with the abundance of a elements in the stellar population, anti-correlates with Hi fraction, and anti-correlates with vertical orbital anisotropy. We expect, if anything, the opposite of these three trends for feedback models. Determining the importance of these correlations will require further model developments and larger observational samples.en_US
dc.description.sponsorshipAlfred P. Sloan Foundationen_US
dc.description.sponsorshipNational Aeronautics and Space Administrationen_US
dc.description.sponsorshipNational Science Foundationen_US
dc.description.sponsorshipU.S. Department of Energyen_US
dc.description.sponsorshipJapanese Monbukagakushoen_US
dc.description.sponsorshipMax Planck Societyen_US
dc.description.sponsorshipUniversity of Chicagoen_US
dc.description.sponsorshipInstitute for Advanced Studyen_US
dc.description.sponsorshipJohns Hopkins Universityen_US
dc.description.sponsorshipLos Alamos National Laboratoryen_US
dc.description.sponsorshipMax-Planck-Institute for Astronomy (MPIA)en_US
dc.description.sponsorshipMax-Planck-Institute for Astrophysics (MPA)en_US
dc.description.sponsorshipNew Mexico State Universityen_US
dc.description.sponsorshipUniversity of Pittsburghen_US
dc.description.sponsorshipUniversity of Portsmouthen_US
dc.description.sponsorshipPrinceton Universityen_US
dc.description.sponsorshipUnited States Naval Observatoryen_US
dc.description.sponsorshipUniversity of Washingtonen_US
dc.identifier.citationAdams, Joshua J., Joshua D. Simon, Maximilian H. Fabricius, Remco CE van den Bosch, John C. Barentine, Ralf Bender, Karl Gebhardt et al. "Dwarf galaxy dark matter density profiles inferred from stellar and gas kinematics." The Astrophysical Journal, Vol. 789, No. 1 (Jul., 2014): 63.en_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectdark matteren_US
dc.subjectgalaxies: dwarfen_US
dc.subjectgalaxies: individual (ngc 0959, ugc 02259,en_US
dc.subjectngc 2552, ngc 2976, ngc 5204, ngc 5949, ugc 11707)en_US
dc.subjectgalaxies: kinematicsen_US
dc.subjectand dynamicsen_US
dc.subjectlow surface brightnessen_US
dc.subjectresolution rotation curvesen_US
dc.subjectinitial mass functionen_US
dc.subjectluminosity spiralen_US
dc.subjectmulti-gaussian expansionen_US
dc.subjectstar-formation historiesen_US
dc.subjectred giant starsen_US
dc.subjectto-light ratioen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleDwarf Galaxy Dark Matter Density Profiles Inferred From Stellar And Gas Kinematicsen_US

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