The Next Generation Virgo Cluster survey. V. Modeling the dynamics of M87 with the made-to-measure method

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DOIResolve DOI: http://doi.org/10.1088/0004-637X/792/1/59
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TypeArticle
Journal titleThe Astrophysical Journal
ISSN0004-637X
Volume792
Issue1
Article number59
Pages118; # of pages: 18
AbstractWe study the dynamics of the giant elliptical galaxy M87 from the central to the outermost regions with the made-to-measure (M2M) method. We use a new catalog of 922 globular cluster line-of-sight velocities extending to a projected radius of 180 kpc (equivalent to 25 M87 effective radii), and SAURON integral field unit data within the central 2.4 kpc. There are 263 globular clusters, mainly located beyond 40 kpc, newly observed by the Next Generation Virgo Survey. For the M2M modeling, the gravitational potential is taken as a combination of a luminous matter potential with a constant stellar mass-to-light ratio and a dark matter potential modeled as a logarithmic potential. Our best-fit dynamical model returns a stellar mass-to-light ratio in the I band of M/LI = 6.0 ± 0.3 with a dark matter potential scale velocity of 591 ± 50 km s-1 and scale radius of 42 ± 10 kpc. We determine the total mass of M87 within 180 kpc to be (1.5 ± 0.2) × 1013 M. The mass within 40 kpc is smaller than previous estimates determined using globular cluster kinematics that did not extend beyond ∼45 kpc. With our new globular cluster velocities at much larger radii, we see that globular clusters around 40 kpc show an anomalously large velocity dispersion which affected previous results. The mass we derive is in good agreement with that inferred from ROSAT X-ray observation out to 180 kpc. Within 30 kpc our mass is also consistent with that inferred from Chandra and XMM-Newton X-ray observations, while within 120 kpc it is about 20% smaller. The model velocity dispersion anisotropy β parameter for the globular clusters in M87 is small, varying from -0.2 at the center to 0.2 at ∼40 kpc, and gradually decreasing to zero at ∼120 kpc.
Publication date
LanguageEnglish
AffiliationNational Science Infrastructure; National Research Council Canada
Peer reviewedYes
NPARC number21272890
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Record identifierf97b4f00-ffb9-4646-9627-59d27249f604
Record created2014-12-03
Record modified2016-07-18
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