The Masses of the Milky Way and Andromeda galaxies

By L. Watkins, N. Evans II, J. A. IoA, Cambridge, Nao, Beijing, China. 2010

297 citations recorded by the source corpus.

We present a family of robust tracer mass estimators to compute the enclosed mass of galaxy haloes from samples of discrete positional and kinematical data of tracers, such as halo stars, globular clusters and dwarf satellites. The data may be projected positions, distances, lineof-sight velocities or proper motions. The estimators all assume that the tracer population has a scale-free density and moves in a scale-free potential in the region of interest. The circumstances under which the boundary terms can be discarded and the estimator converges are derived. Forms of the estimator tailored for the Milky Way Galaxy and for M31 are given. Monte Carlo simulations are used to quantify the uncertainty as a function of sample size. For the Milky Way Galaxy, the satellite sample consists of 26 galaxies with line-of-sight velocities. We find that the mass of the Milky Way within 300 kpc is M300 = 0.9 ± 0.3 ×

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/dff71906adf4bd0c1bee24e22510e741a1853eda

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

The mass distribution and gravitational potential of the Milky Way (2016, methodology): “Watkins et al.(2010) used a sample of 26 satellite galaxies (including six with proper motions) to find the mass of the Milky Way within 300 kpc, and found that the answer depended sensitively on the assumed velocity anisotropy of the satellites, with a mass estimate that was (1.4 ± 0.3) × 1012 M⊙…”
A METHOD FOR MEASURING (SLOPES OF) THE MASS PROFILES OF DWARF SPHEROIDAL GALAXIES (2011, methodology): “Watkins et al. (2010) have recently used a sample of tracers (halo stars, globular clusters and satellite galaxies) in the outer Galactic halo to estimate a mass of MMW(≤ 300kpc) = 0.9± 0.3× 1012M⊙.”
THE M31 VELOCITY VECTOR. II. RADIAL ORBIT TOWARD THE MILKY WAY AND IMPLIED LOCAL GROUP MASS (2012, methodology): “Furthermore, the mass of the LG has been estimated independently by adding up the individual masses of the MW and M31, as estimated from various dynamical tracers (e.g., Klypin et al. 2002; Watkins et al. 2010).”
The Milky Way’s bright satellites as an apparent failure of ΛCDM (2011, background): “Watkins et al. (2010) find a “best estimate” – including Leo I – of M(< 300 kpc) = (2.7 ± 0.5) × 1012 M , which assumes that the satellite orbits are tangentially biased (based on observed proper motions); this estimate becomes (1.4±0.3)×1012 M for isotropic orbits, and (1.2 ± 0.2) × 1012 M for…”
Galaxy Masses: A Review (2013, background): “Recently, Watkins et al. (2010) carried out a detailed systematic study of mass estimators for both the Milky Way and Andromeda galaxies based on satellite kinematics.”
THE MILKY WAY'S CIRCULAR-VELOCITY CURVE BETWEEN 4 AND 14 kpc FROM APOGEE DATA (2012, background): “This “low” estimate for the mass of the Milky Way likely makes it less massive than M31, which has an estimated dark-halo mass of 14× 1011 M⊙ (Watkins et al. 2010).”
WIDE-FIELD PRECISION KINEMATICS OF THE M87 GLOBULAR CLUSTER SYSTEM (2011, unknown): “…between observed dispersion and circular velocity can then be expressed as a constant: vc(r = Rp) = kσp(Rp), where k2 ≡ (α+ γ)(α+ γ − 2β) α+ γ − (α+ γ − 1)β Γ[(α + γ)/2]Γ[(α− 1)/2] Γ[(α+ γ − 1)/2]Γ[α/2] (7) (Dekel et al. 2005; see also Efstathiou et al. 1980; Gerhard 1993; Watkins et al. 2010).”
Hunting for the Dark Matter Wake Induced by the Large Magellanic Cloud (2019, methodology): “Strong variations in the kinematics of the stellar and DM halo (i.e. in β) across the sky will cause variations in estimates of the mass of the MW inferred through Jeans modelling (e.g., Watkins et al. 2010).”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, result): “…in higher values, M 200 = 1–2 × 1012 M when the Leo I dwarf satellite galaxy is assumed to be bound to the Milky Way; however, if Leo I with its large LOS velocity is considered unbound, values more similar to M 200 1012 M result (Wilkinson & Evans 1999, Li & White 2008, Watkins et al. 2010).”
Is there a "too big to fail" problem in the field? (2014, background): “A MW mass in this range is on the low side of observational estimates (e.g. Watkins et al. 2010), and is lower than typically assumed in DM simulations of MW analogs.”
Galactic Searches for Dark Matter (2012, background): “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).”
Galactic accretion and the outer structure of galaxies in the CDM model (2013, methodology): “13 by M31 (black point; Watkins et al. 2010; Courteau et al. 2011) and the Milky Way (grey box; Smith et al. 2007; Bell et al. 2008; Li & White 2008).”
ON THE SHOULDERS OF GIANTS: PROPERTIES OF THE STELLAR HALO AND THE MILKY WAY MASS DISTRIBUTION (2014, methodology): “An alternative approach is the tracer mass formalism (Bahcall & Tremaine 1981; Watkins et al. 2010) which is based on moments.”
KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS (2012, methodology): “…et al. 2007), the local escape speed (Smith et al. 2007), the timing argument (Li & White 2008) and the study of the kinematic of the tracers population (Kochanek 1996; Xue et al. 2008; Gnedin et al. 2010; Watkins et al. 2010) are the methods undertaken in order to constrain the mass of the Galaxy.”
The RAVE survey : the Galactic escape speed and the mass of the Milky Way (2013, background): “Watkins et al. (2010) report an only slightly higher value based on the line-of-sight velocities of satellite galaxies (see also Sales et al. 2007), but when they include proper motion estimates they again find a higher mass of 1.4 × 1012 M .”