Revisiting the Role of M31 in the Dynamical History of the Magellanic Clouds

Abstract

We study the dynamics of the Magellanic Clouds in a model for the Local Group whose mass is constrained using the timing argument/two-body limit of the action principle. The goal is to evaluate the role of M31 in generating the high angular momentum orbit of the Clouds, a puzzle that has only been exacerbated by the latest $HST$ proper motion measurements. We study the effects of varying the total Local Group mass, the relative mass of the Milky Way and M31, the proper motion of M31, and the proper motion of the LMC on this problem. Over a large part of this parameter-space we find that tides from M31 are insignificant. For a range of LMC proper motions approximately $3\sigma$ higher than the mean and total Local Group mass $>3.5\times 10^{12}{M}_{\odot }$, M31 can provide a significant torque to the LMC orbit. However, if the LMC is bound to the MW, then M31 is found to have negligible effect on its motion and the origin of the high angular momentum of the system remains a puzzle. Finally, we use the timing argument to calculate the total mass of the MW-LMC system based on the assumption that they are encountering each other for the first time, their previous perigalacticon being a Hubble time ago, obtaining $M_{\mathrm{MW}}+M_{\mathrm{LMC}}=(8.7\pm 0.8)\times 10^{11}{M}_{\odot }$.

10 pages, 5 figures, accepted to ApJ

References in corpus (12)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• Is the SMC Bound to the LMC? The HST Proper Motion of the SMC
• M31 Transverse Velocity and Local Group Mass from Satellite Kinematics
• The Collision Between The Milky Way And Andromeda
• Milky Way potentials in CDM and MOND. Is the Large Magellanic Cloud on a bound orbit?
• The Proper Motion of the Local Group Galaxy IC 10
• Implications of Recent Measurements of the Milky Way Rotation for the Orbit of the Large Magellanic Cloud
• The Dwarf Satellites of M31 and the Galaxy
• A possible common halo of the Magellanic Clouds
• Dark energy and the mass of the Local Group

Cited by in corpus (7)

• Orbits of Massive Satellite Galaxies: I. A Close Look at the Large Magellanic Cloud and a New Orbital History for M33
• The M31 Velocity Vector. III. Future Milky Way-M31-M33 Orbital Evolution, Merging, and Fate of the Sun
• Galaxy And Mass Assembly (GAMA): In Search of Milky-Way Magellanic Cloud Analogues
• Systematic uncertainties from halo asphericity in dark matter searches
• UGC 4703 interacting pair near to an isolated spiral galaxy NGC 2718: A Milky Way Magellanic Cloud analogue
• Tracing the Magellanic Clouds Back in Time
• Timing Mass of the Local Group