Formation of Andromeda II via a gas-rich major merger and an interaction with M31

Abstract

Andromeda II (And II) has been known for a few decades but only recently observations have unveiled new properties of this dwarf spheroidal galaxy. The presence of two stellar populations, the bimodal star formation history (SFH) and an unusual rotation velocity of And II put strong constrains on its formation and evolution. Following Lokas et al. (2014), we propose a detailed model to explain the main properties of And II involving (1) a gas-rich major merger between two dwarf galaxies at high redshift in the field and (2) a close interaction with M31 about 5 Gyr ago. The model is based on N-body/hydrodynamical simulations including gas dynamics, star formation and feedback. One simulation is designed to reproduce the gas-rich major merger explaining the origin of stellar populations and the SFH. Other simulations are used to study the effects of tidal forces and the ram pressure stripping during the interaction between And II and M31. The model successfully reproduces the SFH of And II including the properties of stellar populations, its morphology, kinematics and the lack of gas. Further improvements to the model are possible via joint modelling of all processes and better treatment of baryonic physics.

arXiv comment15 pages, 14 figures, 2 tables, accepted for publication in MNRAS

References in corpus (66)

• The Structure of Cold Dark Matter Halos
• The cosmological simulation code GADGET-2
• The observed properties of dwarf galaxies in and around the Local Group
• GADGET: A code for collisionless and gasdynamical cosmological simulations
• At the heart of the matter: the origin of bulgeless dwarf galaxies and Dark Matter cores
• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies
• Fundamental differences between SPH and grid methods
• Eight New Milky Way Companions Discovered in First-Year Dark Energy Survey Data
• Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds
• The Star Formation Histories of Local Group Dwarf Galaxies I. Hubble Space Telescope / Wide Field Planetary Camera 2 Observations
• A New Milky Way Dwarf Galaxy in Ursa Major
• A Faint New Milky Way Satellite in Bootes
• HI in Local Group Dwarf Galaxies and Stripping by the Galactic Halo
• The Haunted Halos of Andromeda and Triangulum: A panorama of galaxy formation in action
• A New Milky Way Dwarf Satellite in Canes Venatici
• Little Things
• The Metamorphosis of Tidally Stirred Dwarf Galaxies
• The Masses of the Milky Way and Andromeda galaxies
• Feedback in simulations of disc-galaxy major mergers
• Equilibrium Disk-Bulge-Halo Models for the Milky Way and Andromeda Galaxies
• Constraining the Milky Way's Hot Gas Halo with OVII and OVII Emission Lines
• Orbital Parameters of Merging Dark Matter Halos
• Sagittarius II, Draco II and Laevens 3: three new Milky Way satellites discovered in the Pan-STARRS 1 3pi Survey
• A Pair of Bootes: A New Milky Way Satellite
• Dynamical Blueprints for Galaxies
• Comparing AMR and SPH Cosmological Simulations: I. Dark Matter & Adiabatic Simulations
• Structural parameters for the M31 dwarf spheroidals
• The dynamics of isolated Local Group galaxies
• Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe
• On the Efficiency of the Tidal Stirring Mechanism for the Origin of Dwarf Spheroidals: Dependence on the Orbital and Structural Parameters of the Progenitor Disky Dwarfs
• PAndAS' cubs: discovery of two new dwarf galaxies in the surroundings of the Andromeda and Triangulum galaxies
• The Dearth of Neutral Hydrogen in Galactic Dwarf Spheroidal Galaxies
• Leo P: An Unquenched Very Low-Mass Galaxy
• The M31 Velocity Vector. I. Hubble Space Telescope Proper Motion Measurements
• The SPLASH Survey: Internal Kinematics, Chemical Abundances, and Masses of the Andromeda I, II, III, VII, X, and XIV dSphs
• Satellite Dwarf Galaxies in a Hierarchical Universe: The Prevalence of Dwarf-Dwarf Major Mergers
• Does M31 result from an ancient major merger?
• The ISLAndS project II: The Lifetime Star Formation Histories of Six Andromeda dSphs
• The remnant of a merger between two dwarf galaxies in Andromeda II
• Lacerta I and Cassiopeia III: Two luminous and distant Andromeda satellite dwarf galaxies found in the 3π Pan-STARRS1 survey
• Discovery of a Faint Old Stellar System at 150 kpc
• Stellar Kinematics of the Andromeda II Dwarf Spheroidal Galaxy
• Tidal evolution of disky dwarf galaxies in the Milky Way potential: the formation of dwarf spheroidals
• Mergers and the outside-in formation of dwarf spheroidals
• Local Group Dwarf Elliptical Galaxies: I. Mapping the Dynamics of NGC 205 Beyond the Tidal Radius
• Gas Loss by Ram Pressure Stripping and Internal Feedback From Low Mass Milky Way Satellites
• The grouping, merging and survival of subhaloes in the simulated Local Group
• Disk-Bulge-Halo Models for the Andromeda Galaxy
• A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part I)
• A single-merger scenario for the formation of the giant stream and the warp of M31
• The Transverse velocity of the Andromeda system, derived from the M31 satellite population
• Deconstructing dwarf galaxies: a Suprime-Cam survey of Andromeda II
• The resonant nature of tidal stirring of disky dwarf galaxies orbiting the Milky Way
• Merger traces in the spatial distribution of stellar populations in the Fornax dSph galaxy
• Loops formed by tidal tails as fossil records of a major merger
• Evolutionary tracks of tidally stirred disky dwarf galaxies
• The shapes of Milky Way satellites: looking for signatures of tidal stirring
• Formation of Dwarf Spheroidal Galaxies Via Mergers of Disky Dwarfs
• Andromeda II as a merger remnant
• A decrease of the gas exchanges between galaxies and the IGM, from 12 to 6 billion years ago
• The origin of prolate rotation in dwarf spheroidal galaxies formed by mergers of disky dwarfs
• Rotating stellar populations in the Fornax dSph galaxy
• A survey of HI gas toward the Andromeda Galaxy
• The post-infall evolution of a satellite galaxy
• The tangential velocity of M31: CLUES from constrained simulations

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• The ultra-diffuse galaxy NGC 1052-DF2 with MUSE: I. Kinematics of the stellar body
• Prolate rotation and metallicity gradient in the transforming dwarf galaxy Phoenix
• Elemental Abundances in M31: The Kinematics and Chemical Evolution of Dwarf Spheroidal Satellite Galaxies
• Multiple Chemodynamic Stellar Populations of the Ursa Minor Dwarf Spheroidal Galaxy
• Satellites of Milky Way- and M31-like galaxies with TNG50: quenched fractions, gas content, and star formation histories
• Galaxies with prolate rotation in Illustris
• Appearances can be deceiving: clear signs of accretion in the seemingly ordinary Sextans dSph
• The distinct stellar metallicity populations of simulated Local Group dwarfs
• Tidally induced morphology of M33 in hydrodynamical simulations of its recent interaction with M31
• The structure of Andromeda II dwarf spheroidal galaxy
• Ubiquitous signs of interactions in early-type galaxies with prolate rotation
• Origin of stellar prolate rotation in a cosmologically simulated faint dwarf galaxy
• Evolution of dwarf galaxy observable parameters
• Observation of HI around three satellite galaxies of the M31 with the FAST: Andromeda II, NGC 205, and NGC 185
• Dark matter distribution and dynamics of dwarf spheroidal galaxies
• The major merger origin of the Andromeda II kinematics