The Mass of the Milky Way: Limits from a newly assembled set of halo objects

By T. Sakamoto, M. Chiba, Timothy C. Beers. 2002

159 citations recorded by the source corpus.

We set new limits on the mass of the Milky Way, making use of the latest kinematic information for Galactic satellites and halo objects. Our sample consists of 11 satellite galaxies, 137 globular clusters, and 413 field horizontal-branch (FHB) stars up to distances of 10 kpc from the Sun. Roughly half of the objects in this sample have measured proper motions, permitting the use of their full space motions in our analysis. In order to bind these sample objects to the Galaxy, their rest-frame velocities must be lower than their escape velocities at their estimated distances. This constraint enables us to show that the mass estimate of the Galaxy is largely aected by several high-velocity objects (Leo I, Pal 3, Draco, and a few FHB stars), not by a single object alone (such as Leo I), as has often been the case in past analyses. We also find that a gravitational potential that gives rise to a declining rotation curve is insucient to bind many of our sample objects to the Galaxy; a possible lower limit on the mass of the Galaxy is about 2:2 10 12 M. To be more quantitative, we adopt a Bayesian likelihood approach to reproduce the observed distribution of the current positions and motions of the sample, in a prescribed Galactic potential that yields a flat rotation curve. This method enables a search for the most likely total mass of the Galaxy, without undue influence in the final result arising from the presence or absence of Leo I, provided that both radial velocities and proper motions are used. Although the best mass estimate depends somewhat on the model assumptions, such as the unknown prior probabilities for the model parameters, the resultant systematic change in the mass estimate is confined to a relatively narrow range of a few times 10 11 M, owing to our consideration of many FHB stars. The most likely total mass derived from this method is 2:5 +0:5 1:0 10 12 M

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/f046276cb71c66e50e2f4baebf725e3324a1ae0c

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Citations in the corpus

THE SAGITTARIUS DWARF GALAXY: A MODEL FOR EVOLUTION IN A TRIAXIAL MILKY WAY HALO (2010, methodology): “The mass of the Milky Way within 50 kpc in this model is 4.4 × 1011M⊙ (i.e., slightly smaller than that obtained by Sakamoto et al. 2003), corresponding to a halo scaling parameter vhalo = 121.9 km s −1 (see Equation 3).”
How do galaxies populate dark matter haloes (2009, unknown): “Estimates, in units of 1012M⊙, include 1.9 +3.6 −1.7 (Wilkinson & Evans 1999), 2.5+0.5 −1.0 or 1.8 +0.4 −0.7 (Sakamoto et al. 2003), depending on whether or not Leo I is included (see also, Li & White 2008, for the former case), 1.42+1.14 −0.54 (Smith & et al. 2007), 0.5 − 1.5 (Battaglia et al.…”
Evidence for an Intermediate-mass Milky Way from Gaia DR2 Halo Globular Cluster Motions (2018, unknown): “There are a number of previous estimates of the mass within 50 kpc including 0.54+0.02−0.36 × 1012 M (Wilkinson & Evans 1999), 0.55+0.00−0.02 × 1012 M (Sakamoto et al. 2003), and 0.42 ± 0.04 × 1012 M (Deason et al. 2012).”
`Skinny Milky Way please', says Sagittarius (2014, background): “Other attempts at mass measurement have used the motion of the population of the Galactic dwarf satellites and globular clusters (e.g Little & Tremaine 1987; Zaritsky et al. 1989; Wilkinson & Evans 1999; Sakamoto et al. 2003; Watkins et al. 2010).”
A novel determination of the local dark matter density (2009, unknown): “The values which we considered in our analysis are [40]”
Pre-Processing of Galaxies before Entering a Cluster (2003, methodology): “The mass of the bigger galaxy (2× 1011 M ) is based on the traditional Galaxy mass (e.g. Allen 1973), although recent studies show that the mass of the Galaxy is much larger (Sakamoto et al. 2003).”
Determination of the Local Dark Matter Density in our Galaxy (2009, methodology): “radius. They found a mass of the Galaxy within 50 kpc of M(50 kpc) = 5.4+0.2 −3.6 · 10 11 M⊙ and a total mass of Mtot = 1.9+3.6 −1.7 · 10 12 M ⊙. A similar analysis was done with more tracer stars by Sakamoto et al. (2003); they ﬁnd M tot = 2.5+0.5 −1.0 · 10 12 M ⊙. These measurements used a simple ”
Galactic Searches for Dark Matter (2012, unknown): “Many authors have improved upon this analysis using both better theoretical models and observational samples (Little and Tremaine, 1987; Zaritsky et al., 1989; Kulessa and Lynden-Bell, 1992; Kochanek, 1996; Wilkinson and Evans, 1999; Sakamoto et al., 2003; Watkins et al., 2010).”
A synthetic view on structure and evolution of the Milky Way (2003, result): “These values are in good agreement with the detailed analysis of the Galactic mass by Sakamoto et al. (2003), from the latest kinematics of Galactic satellites, halo globular clusters and horizontal branch stars, which estimates the Galactic mass to 5.5+0.1−0.4×1011 M within 50 kpc and about…”
Milky Way mass models for orbit calculations (2012, methodology): “In Model II, the halo is replaced by the truncated, flat rotation curve model used in Wilkinson & Evans (1999) and Sakamoto et al. (2003).”
KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS (2012, result): “Our estimate for Mvir is in good agreement with the most of the recent estimates namely by Watkins et al. (2010); Kochanek (1996); Wilkinson & Evans (1999); Sakamoto et al. (2003); Sofue et al. (2009); Watkins et al. (2010); Deason et al. 14 (2012b) as demonstrated in Figure 11.”
There's no place like home? Statistics of Milky Way-mass dark matter haloes (2009, background): “Recent estimates of the mass of the Galaxy’s dark matter halo range from 1 − 3 × 1012 M (Wilkinson & Evans 1999; Sakamoto et al. 2003; Battaglia et al. 2005; Dehnen et al. 2006; Xue et al. 2008; Li & White 2008).”
The Velocity Dispersion Profile of the Remote Dwarf Spheroidal Galaxy Leo I: A Tidal Hit and Run? (2007, background): “Indeed, Leo I can single-handedly inflate the inferred mass of our Galaxy by nearly a factor of 5 compared to dynamical analyses of kinematic samples that exclude it (Zaritsky et al. 1989; Fich & Tremaine 1991; Kochanek 1996; Wilkinson & Evans 1999; Sakamoto et al. 2003).”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, unknown): “…for the Galaxy Reference Method M200 M100 Mrkpc R200 R100 r Wilkinson & Evans (1999) Distribution function based 1.67 2.39 0.54 243.9 346.0 50 Sakamoto et al. (2003) Mixed halo object kinematics 1.67 2.39 0.54 243.9 346.0 50 Dehnen et al. (2006) Halo star kinematics 1.75 1.96 1.05 247.7…”