A constant dark matter halo surface density in galaxies |
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| Authors: | F Donato G Gentile P Salucci C Frigerio Martins M I Wilkinson G Gilmore E K Grebel A Koch R Wyse |
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| Institution: | Universitàdegli Studi di Torino and INFN, via Giuria 1, 10125 Torino, Italy;Institut d'Astronomie et d'Astrophysique, UniversitéLibre de Bruxelles, CP 226, Boulevard du Triomphe, B-1050 Bruxelles, Belgium;Sterrenkundig Observatorium, Ghent University, Krijgslaan 281, S9, B-9000 Ghent, Belgium;Department of Astrophysics, SISSA, via Beirut, 2-4, 34014 Trieste, Italy;Universidade Federal do ABC, Rua Catequese 242, 09090-400 Santo André, Brazil;Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH;Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 OHA;Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr 12-14, D-69120 Heidelberg, Germany;Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Los Angeles, CA 90095-1547, USA;Johns Hopkins University, 366 Bloomberg Center, 3400 North Charles Street, Baltimore, MD 21218, USA |
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| Abstract: | We confirm and extend the recent finding that the central surface density μ0D≡ r 0ρ0 of galaxy dark matter haloes, where r 0 and ρ0 are the halo core radius and central density, is nearly constant and independent of galaxy luminosity. Based on the co-added rotation curves (RCs) of ∼1000 spiral galaxies, the mass models of individual dwarf irregular and spiral galaxies of late and early types with high-quality RCs, and the galaxy–galaxy weak-lensing signals from a sample of spiral and elliptical galaxies, we find that log μ0D= 2.15 ± 0.2 in units of log(M⊙ pc−2) . We also show that the observed kinematics of Local Group dwarf spheroidal galaxies are consistent with this value. Our results are obtained for galactic systems spanning over 14 mag, belonging to different Hubble types and whose mass profiles have been determined by several independent methods. In the same objects, the approximate constancy of μ0D is in sharp contrast to the systematical variations, by several orders of magnitude, of galaxy properties, including ρ0 and central stellar surface density. |
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| Keywords: | galaxies: kinematics and dynamics galaxies: spiral dark matter |
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