A dynamics-free lower bound on the mass of our Galaxy

Dennis Zaritsky, Helene Courtois

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


We use a sample of Milky Way (MW) analogues for which we have stellar and disc gas mass measurements, published measurements of halo gas masses of the MW and of similar galaxies, and the well-established value of the cosmological baryon fraction to place a lower bound on the mass of the Galaxy of 7.7 × 1011M and estimate that the mass is likely to be ≥1.2 × 1012 M. Although most dynamical analyses yield measurements consistent with these results, several recent studies have advocated for a total mass well below 1012M. We reject such low-mass estimates because they imply a Galactic baryon matter fraction significantly above the universal value. Convergence between dynamical mass estimates and those based on the baryonic mass is an important milestone in our understanding of galaxies.

Original languageEnglish (US)
Pages (from-to)3724-3728
Number of pages5
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
StatePublished - Mar 1 2017


  • Galaxy: fundamental parameters

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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