IMPROVED ESTIMATES OF THE MILKY WAY’S STELLAR MASS AND STAR FORMATION RATE FROM HIERARCHICAL BAYESIAN META-ANALYSIS

By Timothy C. Licquia, J. Newman. 2014

244 citations recorded by the source corpus.

We present improved estimates of several global properties of the Milky Way, including its current star formation rate (SFR), the stellar mass contained in its disk and bulge+bar components, as well as its total stellar mass. We do so by combining previous measurements from the literature using a hierarchical Bayesian (HB) statistical method that allows us to account for the possibility that any value may be incorrect or have underestimated errors. We show that this method is robust to a wide variety of assumptions about the nature of problems in individual measurements or error estimates. Ultimately, our analysis yields an SFR for the Galaxy of M ˙ ⋆ = 1.65 ± 0.19 M ⊙ yr - 1 ?> , assuming a Kroupa initial mass function (IMF). By combining HB methods with Monte Carlo simulations that incorporate the latest estimates of the Galactocentric radius of the Sun, R0, the exponential scale length of the disk, Ld, and the local surface density of stellar mass, &Sgr; ⋆ ( R 0 ) ?> , we show that the mass of the Galactic bulge+bar is M ⋆ B = 0.91 ± 0.07 × 10 10 ?> M ⊙ ?> , the disk mass is M ⋆ D = 5.17 ± 1.11 × 10 10 ?> M ⊙ ?> , and their combination yields a total stellar mass of M ⋆ = 6.08 ± 1.14 × 10 10 ?> M ⊙ ?> (assuming a Kroupa IMF and an exponential disk profile). This analysis is based upon a new compilation of literature bulge mass estimates, normalized to common assumptions about the stellar IMF and Galactic disk properties, presented herein. We additionally find a bulge-to-total mass ratio for the Milky Way of B / T = 0.150 − 0.019 + 0.028 ?> and a specific SFR of M ˙ ⋆ / M ⋆ = 2.71 ± 0.59 × 10 − 11 ?> yr−1.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d9e4b3e637c8e829ba0842e7f47fc52ff6ef0e6f

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In Astronomy and Astrophysics

Citations in the corpus

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation (2016, background): “The Milky Way to date is the best resolved dynamical measurementof a central black hole withMbh ∼ 4.3× 106 M⊙, σ ∼ 200 km s−1 (Scott et al. 2013) and stellar mass ofl gMstar ∼ 10.7 (e.g., Licquia & Newman 2015, for a Chabrier IMF).”
A fast radio burst associated with a Galactic magnetar (2020, background): “19 M yr−1 [40], and a volumetric star formation rate of 1.”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, background): “Licquia & Newman (2015) revisit this work and conclude that ṁ = 1.65±0.19 M year−1 for an adopted Kroupa IMF.”
RECONCILING DWARF GALAXIES WITH ΛCDM COSMOLOGY: SIMULATING A REALISTIC POPULATION OF SATELLITES AROUND A MILKY WAY–MASS GALAXY (2016, unknown): “For comparison, the MW has Mstar = 6 × 1010 M and SFR = 1.7 M yr −1 (Licquia & Newman 2015); M31 has Mstar ≈ 1011 M and SFR ≈ 0.7 M yr−1 (Tamm et al. 2012; Lewis et al. 2015).”