Repozytorium Uniwersytetu Jagiellońskiego

A lower bound on the Milky Way mass from general phase-spacedistribution function models

A lower bound on the Milky Way mass from general ...

Metadane (Dublin Core)

dc.contributor.author Sikora, Szymon [SAP14012983] pl
dc.contributor.author Jałocha, Joanna pl
dc.contributor.author Kutschera, Marek [SAP11116629] pl
dc.contributor.author Bratek, Łukasz pl
dc.date.accessioned 2015-02-19T14:43:32Z
dc.date.available 2015-02-19T14:43:32Z
dc.date.issued 2014 pl
dc.identifier.issn 0004-6361 pl
dc.identifier.uri http://ruj.uj.edu.pl/xmlui/handle/item/3209
dc.language eng pl
dc.title A lower bound on the Milky Way mass from general phase-spacedistribution function models pl
dc.type JournalArticle pl
dc.abstract.en We model the phase-space distribution of the kinematic tracers using general, smooth distribution functions to derive a conservative lower bound on the total mass within ≈150−200   kpc. By approximating the potential as Keplerian, the phase-space distribution can be simplified to that of a smooth distribution of energies and eccentricities. Our approach naturally allows for calculating moments of the distribution function, such as the radial profile of the orbital anisotropy. We systematically construct a family of phase-space functions with the resulting radial velocity dispersion overlapping with the one obtained using data on radial motions of distant kinematic tracers, while making no assumptions about the density of the tracers and the velocity anisotropy parameter β regarded as a function of the radial variable. While there is no apparent upper bound for the Milky Way mass, at least as long as only the radial motions are concerned, we find a sharp lower bound for the mass that is small. In particular, a mass value of 2.4   ×   1011 M⊙, obtained in the past for lower and intermediate radii, is still consistent with the dispersion profile at larger radii. Compared with much greater mass values in the literature, this result shows that determining the Milky Way mass is strongly model-dependent. We expect a similar reduction of mass estimates in models assuming more realistic mass profiles. pl
dc.subject.en techniques: radial velocities pl
dc.subject.en Galaxy: halo pl
dc.subject.en Galaxy: kinematics and dynamics pl
dc.subject.en Galaxy: fundamental parameters pl
dc.subject.en methods: numerical pl
dc.description.volume 562 pl
dc.identifier.doi 10.1051/0004-6361/201322617 pl
dc.identifier.eissn 1432-0746 pl
dc.title.journal Astronomy and Astrophysics pl
dc.language.container eng pl
dc.affiliation Wydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut – Obserwatorium Astronomiczne pl
dc.affiliation Wydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut Fizyki im. Mariana Smoluchowskiego pl
dc.subtype Article pl
dc.identifier.articleid A134 pl
dc.rights.original CC-BY-NC; otwarte czasopismo; ostateczna wersja wydawcy; po opublikowaniu; 12; pl
.pointsMNiSW [2014 A]: 35


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