Signatures of the M31-M32 Galactic Collision

Abstract

The unusual morphologies of the Andromeda spiral galaxy (M31) and its dwarf companion M32 have been characterized observationally in great detail. The two galaxies' apparent proximity suggests that Andromeda's prominent star-forming ring as well as M32's compact elliptical structure may result from a recent collision. Here we present the first self-consistent model of the M31-M32 interaction that simultaneously reproduces observed positions, velocities, and morphologies for both galaxies. Andromeda's spiral structure is resolved in unprecedented detail, showing that a rare head-on orbit is not necessary to match Andromeda's ring-like morphology. The passage of M32 through Andromeda's disk perturbs the disk velocity structure. We find tidal stripping of M32's stars to be inefficient during the interaction, suggesting that some cEs are intrinsically compact. Additionally, the orbital solution implies that M32 is currently closer to the Milky Way than models have typically assumed, a prediction that may be testable with upcoming observations.

7 pages, 3 figures

References in corpus (9)

• The Tidal Evolution of Local Group Dwarf Spheroidals
• The M31 Velocity Vector. II. Radial Orbit Towards the Milky Way and Implied Local Group Mass
• A Wide-field High Resolution HI Mosaic of Messier 31: I. Opaque Atomic Gas and Star Formation Rate Density
• An almost head-on collision as the origin of two off-centre rings in the Andromeda galaxy
• The M31 Velocity Vector. I. Hubble Space Telescope Proper Motion Measurements
• M31 Transverse Velocity and Local Group Mass from Satellite Kinematics
• The Collision Between The Milky Way And Andromeda
• Slowly Breaking Waves: The Longevity of Tidally Induced Spiral Structure
• Darwin Tames an Andromeda Dwarf: Unraveling the Orbit of NGC 205 Using a Genetic Algorithm

Cited by in corpus (14)

• The Panchromatic Hubble Andromeda Treasury XI: The Spatially-Resolved Recent Star Formation History of M31
• Orbits of Massive Satellite Galaxies: I. A Close Look at the Large Magellanic Cloud and a New Orbital History for M33
• The (black hole)-bulge mass scaling relation at low masses
• The Herschel Exploitation of Local Galaxy Andromeda (HELGA) VII: A SKIRT radiative transfer model and insights on dust heating
• Predicted Extension of the Sagittarius Stream to the Milky Way Virial Radius
• Bars and spirals in tidal interactions with an ensemble of galaxy mass models
• An isolated, compact early-type galaxy with a diffuse stellar component: merger origin?
• Spiral arms and disc stability in the Andromeda galaxy
• The potential role of NGC 205 in generating Andromeda's vast thin co-rotating plane of satellite galaxies
• The Chemodynamical Nature of the Triangulum-Andromeda Overdensity
• Rings of star formation: Imprints of a close galaxy encounter
• Towards Understanding the Milky Way's Typicality: Assessing the Chemodynamics of M31's Bulge & Bar, Thick & Thin Discs
• Resolved nuclear kinematics link the formation and growth of nuclear star clusters with the evolution of their early and late-type hosts
• The Panchromatic Hubble Andromeda Southern Treasury (PHAST). II. The Spatially Resolved Recent Star Formation History in M31