SIMBAD references

2016MNRAS.457..421O - Mon. Not. R. Astron. Soc., 457, 421-439 (2016/March-3)

Galaxy structure from multiple tracers - II. M87 from parsec to megaparsec scales.

OLDHAM L.J. and AUGER M.W.

Abstract (from CDS):

Following a number of conflicting studies of M87's mass profile, we undertake a dynamical analysis of multiple tracer populations to constrain its mass over a large radius range. We combine stellar kinematics in the central regions with the dynamics of 612 globular clusters out to 200 kpc and satellite galaxies extending to scales comparable with the virial radius. Using a spherical Jeans analysis, we are able to disentangle the mass contributions from the dark and baryonic components and set constraints on the structure of each. Assuming isotropy, we explore four different models for the dark matter halo and find that a centrally cored dark matter distribution is preferred. We infer a stellar mass-to-light ratio U*, v = 6.9 ± 0.1 - consistent with a Salpeter-like initial mass function (IMF) - and a core radius rc = 67 ± 20 kpc. We then introduce anisotropy and find that, while the halo remains clearly cored, the radial stellar anisotropy has a strong impact on both U*, v and the core's radius; here we find - consistent with a Chabrier-like IMF - and kpc. Thus, the presence of a core at the centre of the dark halo is robust against anisotropy assumptions, while the stellar mass and core size are not. We are able to reconcile previously discrepant studies by showing that modelling the globular cluster data alone leads to the very different inference of a super-NFW cusp, thus highlighting the value of multiple-population modelling, and we point to the possible role of M87's AGN and the cluster environment in forming the central dark matter core.

Abstract Copyright: © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): galaxies: elliptical and lenticular, cD - galaxies: haloes - galaxies: individual: M87 - galaxies: kinematics and dynamics - galaxies: structure

Simbad objects: 8

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