On the Adromeda to Milky Way mass-ratio

Abstract

We have explored the hypothesis that the total mass-ratio of the two main galaxies of the Local Group: Andromeda Galaxy(M31) and the Milky Way (MW) can be constrained measuring the tidal force induced by the surrounding mass distribution, M31 included, on the MW. We argue that the total mass-ratio between the two groups can be approximated, at least qualitatively, finding the tidal radius where the internal binding force of the MW balances the external tidal force acting on it. Since M31 is the massive tidal perturber of the local environment, we have used a wide range of M31 to MW mass-ratio combinations to compute the corresponding tidal radii. Of them, only few match the distance of the zero-tidal shell i.e. the shell identified observationally by the outermost dwarf galaxies which do not show any sign of tidal effects. This is the key to constrain the best mass-ratio interval of the two galaxies. Our results favour a solution where the mass-ratio ranges from 2 to 3 implying a massive predominance of M31.

8 pages, 2 figures, Accepted for publication in Mon. Not. of Royal Astron. Soc

References in corpus (17)

• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• The RAVE Survey: Constraining the Local Galactic Escape Speed
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function
• Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy
• Dark matter subhalos and the dwarf satellites of the Milky Way
• Dark matter in the Milky Way, II. the HI gas distribution as a tracer of the gravitational potential
• Leo V: A Companion of a Companion of the Milky Way Galaxy
• The velocity dispersion and mass profile of the Milky Way
• Exploring Halo Substructure with Giant Stars X. Extended Dark Matter or Tidal Disruption?: The Case for the Leo I Dwarf Spheroidal Galaxy
• The Hubble flow around the Local Group
• Modeling The Structure And Dynamics of Dwarf Spheroidal Galaxies with Dark Matter And Tides
• A Revised LCDM Mass Model For The Andromeda Galaxy
• Leo V: Spectroscopy of a Distant and Disturbed Satellite
• Implications of Recent Measurements of the Milky Way Rotation for the Orbit of the Large Magellanic Cloud
• A Method to Constrain the Total Mass of Galaxy Groups

Cited by in corpus (8)

• Kinematics of the stellar halo and the mass distribution of the Milky Way using BHB stars
• On the mass of the Local Group
• Constraining the mass of the Local Group
• Unearthing Foundations of a Cosmic Cathedral: Searching the Stars for M33's Halo
• Estimation of the masses in the Local Group by Gradient Boosted Decision Trees
• On the Mass Assembly History of the Local Group
• An HST/WFPC2 survey of bright young clusters in M31. IV. Ages and mass estimates
• DELVE Milky Way Satellite Galaxy Census I: Satellite Population and Survey Selection Function in DES, DELVE, and Pan-STARRS