Two Disk Components from a Gas Rich Disk-Disk Merger

Abstract

We employ N-body, smoothed particle hydrodynamical simulations, including detailed treatment of chemical enrichment, to follow a gas-rich merger which results in a galaxy with disk morphology. We trace the kinematic, structural and chemical properties of stars formed before, during, and after the merger. We show that such a merger produces two exponential disk components, with the older, hotter component having a scale-length 20% larger than the later-forming, cold disk. Rapid star formation during the merger quickly enriches the protogalactic gas reservoir, resulting in high metallicities of the forming stars. These stars form from gas largely polluted by Type II supernovae, which form rapidly in the merger-induced starburst. After the merger, a thin disk forms from gas which has had time to be polluted by Type Ia supernovae. Abundance trends are plotted, and we examine the proposal that increased star formation during gas-rich mergers may explain the high alpha-to-iron abundance ratios which exist in the relatively high-metallicity thick disk component of the Milky Way.

10 pages, 1 color figure. Accepted for publication in ApJ

References in corpus (29)

• A Universal Density Profile from Hierarchical Clustering
• The Structure of Cold Dark Matter Halos
• Nucleosynthesis in Chandrasekhar Mass Models for Type Ia Supernovae and Constraints on Progenitor Systems and Burning-Front Propagation
• Cold collapse and the core catastrophe
• The Mass-Metallicity Relation at z~2
• Elemental Abundance Survey of The Galactic Thick Disk
• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• Forming Disk Galaxies in Lambda CDM Simulations
• Density profiles and substructure of dark matter halos: converging results at ultra-high numerical resolution
• A Merger-Driven Scenario for Cosmological Disk Galaxy Formation
• Resolving the Structure of Cold Dark Matter Halos II
• Formation of a spiral galaxy in a major merger
• Density Profiles of Dark Matter Halo are not Universal
• The Emergence of the Thick Disk in a CDM Universe
• Structural Parameters of Thin and Thick Disks in Edge-On Disk Galaxies
• GCD+: A New Chemodynamical Approach to Modeling SNe and Chemical Enrichment
• Chemical Abundance Distributions of Galactic Halos and their Satellite Systems in a Lambda CDM Universe
• Implementing Feedback in Simulations of Galaxy Formation: A Survey of Methods
• Observations of Thick Disks in the Hubble Space Telescope Ultra Deep Field
• The History of the Comic Supernova Rate Derived from the Evolution of the Host Galaxies
• Thickening of galactic disks through clustered star formation
• The Emergence of the Thick Disk in a CDM Universe II: Colors and Abundance Patterns
• Gas Mass Fractions and the Evolution of LSB Dwarf Galaxies
• Stellar Halo Constraints on Simulated Late Type Galaxies
• Disk evolution since z=1 in a CDM Universe
• Red thick disks of nearby galaxies
• Probing the Evolution of the Galaxy Interaction/Merger Rate Using Collisional Ring Galaxies
• A Structural and Dynamical Study of Late-Type, Edge-On Galaxies: I. Sample Selection and Imaging Data
• The Stellar Halo Metallicity - Luminosity Relationship for Spiral Galaxies

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• Sausage & Mash: The dual origin of the Galactic thick disc and halo from the gas-rich Gaia-Enceladus-Sausage merger
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• Stellar Metallicities and Kinematics in a Gas-Rich Dwarf Galaxy: First Calcium Triplet Spectroscopy of RGB Stars in WLM
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• Anisotropic Galactic Outflows and Enrichment of the Intergalactic Medium. II. Numerical Simulations
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