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The RAVE survey: the Galactic escape speed and the mass of the Milky Way.
- Source :
-
Astronomy & Astrophysics / Astronomie et Astrophysique . Feb2014, Vol. 562, p1-16. 16p. - Publication Year :
- 2014
-
Abstract
- We made new estimates of the Galactic escape speed at various Galactocentric radii using the latest data release of the RAdial Velocity Experiment (RAVE DR4). Compared to previous studies we have a database that is larger by a factor of 10, as well as reliable distance estimates for almost all stars. Our analysis is based on statistical analysis of a rigorously selected sample of 90 highvelocity halo stars from RAVE and a previously published data set. We calibrated and extensively tested our method using a suite of cosmological simulations of the formation of Milky Way-sized galaxies. Our best estimate of the local Galactic escape speed, which we define as the minimum speed required to reach three virial radii R340, is 533+54 -41 km s-1 (90% confidence), with an additional 4% systematic uncertainty, where R340 is the Galactocentric radius encompassing a mean overdensity of 340 times the critical density for closure in the Universe. From the escape speed we further derived estimates of the mass of the Galaxy using a simple mass model with two options for the mass profile of the dark matter halo: an unaltered and an adiabatically contracted Navarro, Frenk & White (NFW) sphere. If we fix the local circular velocity, the latter profile yields a significantly higher mass than the uncontracted halo, but if we instead use the statistics for halo concentration parameters in large cosmological simulations as a constraint, we find very similar masses for both models. Our best estimate for M340, the mass interior to R340 (dark matter and baryons), is 1.3+0.4 -0.3 × 1012 M☉ (corresponds to M200 = 1.6+0.5 -0.4 × 1012 M☉). This estimate is in good agreement with recently published, independent mass estimates based on the kinematics of more distant halo stars and the satellite galaxy Leo I. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00046361
- Volume :
- 562
- Database :
- Academic Search Index
- Journal :
- Astronomy & Astrophysics / Astronomie et Astrophysique
- Publication Type :
- Academic Journal
- Accession number :
- 94839131
- Full Text :
- https://doi.org/10.1051/0004-6361/201322531