The slowing down of galaxy disks in dissipationless minor mergers

Abstract

We have investigated the impact of dissipationless minor galaxy mergers on the angular momentum of the remnant. Our simulations cover a range of initial orbital characteristics and the system consists of a massive galaxy with a bulge and disk merging with a much less massive (one-tenth or one-twentieth) gasless companion which has a variety of morphologies (disk- or elliptical-like) and central baryonic mass concentrations. During the process of merging, the orbital angular momentum is redistributed into the internal angular momentum of the final system; the internal angular momentum of the primary galaxy can increase or decrease depending on the relative orientation of the orbital spin vectors (direct or retrograde), while the initially non-rotating dark matter halo always gains angular momentum. The specific angular momentum of the stellar component always decreases independent of the orbital parameters or morphology of the satellite, the decrease in the rotation velocity of the primary galaxy is accompanied by a change in the anisotropy of the orbits, and the ratio of rotation speed to velocity dispersion of the merger remnant is lower than the initial value, not only due to an increase in the dispersion but also to the slowing -down of the disk rotation. We briefly discuss several astrophysical implications of these results, suggesting that minor mergers do not cause a "random walk" process of the angular momentum of the stellar disk component of galaxies, but rather a steady decrease. Minor mergers may play a role in producing the large scatter observed in the Tully-Fisher relation for S0 galaxies, as well as in the increase of the velocity dispersion and the decrease in $v/\sigma$ at large radii as observed in S0 galaxies.

arXiv comment10 pages, 10 figures, accepted for publication in A&A

References in corpus (52)

• The Formation of Galactic Disks
• The SAURON project -- IX. A kinematic classification for early-type galaxies
• The Ghost of Sagittarius and Lumps in the Halo of the Milky Way
• The subhalo populations of LCDM dark haloes
• Simulations of Galaxy Formation in a Lambda CDM Universe II: The Fine Structure of Simulated Galactic Disks
• A giant stream of metal-rich stars in the halo of the galaxy M31
• The Secular Evolution of Disk Structural Parameters
• Quantifying the Fragility of Galactic Disks in Minor Mergers
• Statistical Properties of Collisionless Equal- and Unequal-Mass Merger Remnants of Disk Galaxies
• A Low Latitude Halo Stream around the Milky Way
• The origin of angular momentum in dark matter halos
• The structure of galactic disks: Studying late-type spiral galaxies using SDSS
• Galaxy mergers with various mass ratios: properties of remnants
• Sinking Satellites and the Heating of Galaxy Discs
• Cold Dark Matter Substructure and Galactic Disks I: Morphological Signatures of Hierarchical Satellite Accretion
• Feedback, Disk Self-regulation and Galaxy Formation
• Fossil Signatures of Ancient Accretion Events in the Halo
• Multiple minor mergers: formation of elliptical galaxies and constraints for the growth of spiral disks
• The Nearly Universal Merger Rate of Dark Matter Haloes in Lambda-CDM Cosmology
• On the accretion origin of a vast extended stellar disk around the Andromeda galaxy
• History of Galaxy Interactions and their Impact on Star Formation over the Last 7 Gyr from GEMS
• Anti-Truncation of Disks in Early-Type Barred Galaxies
• Kinematic properties of early-type galaxy haloes using planetary nebulae
• Properties of Bars and Bulges in the Hubble Sequence
• The mass distribution in early-type disk galaxies: declining rotation curves and correlations with optical properties
• The role of minor mergers in the recent star formation history of early-type galaxies
• The Angular Momentum Content of Dwarf Galaxies: New Challenges for the Theory of Galaxy Formation
• Cold Dark Matter Substructure and Galactic Disks II: Dynamical Effects of Hierarchical Satellite Accretion
• On the Formation of Boxy and Disky Elliptical Galaxies
• The line of sight velocity distributions of simulated merger remnants
• Specific Angular Momentum of Disc Merger Remnants and the ${\lambda }_R$-Parameter
• Antitruncated Stellar Disks via Minor Mergers
• Can Gas prevent the Destruction of Thin Stellar Discs by Minor Mergers?
• Heating of Galactic Disks by Infalling Satellites
• Formation and evolution of galactic disks with a multiphase numerical model
• The Tully-Fisher relation for S0 galaxies
• Tidal streams in the Galactic halo: Evidence for the Sagittarius northern stream or traces of a new nearby dwarf galaxy
• Unequal-mass galaxy merger remnants: spiral-like morphology but elliptical-like kinematics
• Halo Substructure and Disk Heating in a Lambda CDM Universe
• Bulgeless Galaxies and their Angular Momentum Problem
• On the Origin of Dynamically Cold Rings Around the Milky Way
• Tidal debris in elliptical galaxies as tracers of mergers with disks
• Bar-Halo Friction in Galaxies II: Metastability
• The puzzlingly large Ca II triplet absorption in dwarf elliptical galaxies
• Large stellar disks in small elliptical galaxies
• Kinematic constraints on the stellar and dark matter content of spiral and S0 galaxies
• The kinematics of 3:1-merger remnants and the formation of low-luminosity elliptical galaxies
• Testing the nature of S0 galaxies using planetary nebula kinematics in NGC 1023
• Generation of rotationally dominated galaxies by mergers of pressure-supported progenitors
• The dynamics of S0 galaxies and their Tully-Fisher relation
• The haloes of merger remnants
• Spiral-like Light Profiles but Elliptical-like Kinematics in Mergers of Galaxies

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• Theoretical Challenges in Galaxy Formation
• The ATLAS${}^{3D}$ project - XXV: Two-dimensional kinematic analysis of simulated galaxies and the cosmological origin of fast and slow rotators
• The Milky Way has no in-situ halo other than the heated thick disc. Composition of the stellar halo and age-dating the last significant merger with Gaia DR2 and APOGEE
• The Atlas3D Project - VI. Simulations of binary galaxy mergers and the link with Fast Rotators, Slow Rotators, and Kinematically Distinct Cores
• On the kinematic detection of accreted streams in the Gaia era: a cautionary tale
• The Fossil Record of Two-phase Galaxy Assembly: Kinematics and Metallicities in the Nearest S0 Galaxy
• The Origin and Evolution of Fast and Slow Rotators in the Illustris Simulation
• The Dark Halo - Spheroid Conspiracy and the Origin of Elliptical Galaxies
• Characteristics of thick disks formed through minor mergers: stellar excesses and scale lengths
• Exploring the mass assembly of the early-type disc galaxy NGC3115 with MUSE
• Formation of S0 galaxies through mergers. Evolution in the Tully-Fisher relation since $z\sim 1$
• Star Formation Suppression in Compact Group Galaxies: A New Path to Quenching?
• Minor mergers and their impact on the kinematics of old and young stellar populations in disk galaxies
• Fate of stellar bars in minor merger of galaxies
• MaNGA DynPop -- III. Stellar dynamics versus stellar population relations in 6000 early-type and spiral galaxies: Fundamental Plane, mass-to-light ratios, total density slopes, and dark matter fractions
• Welcome to the Twilight Zone: The Mid-Infrared Properties of Poststarburst Galaxies
• The dawn of disks: unveiling the turbulent ionised gas kinematics of the galaxy population at $z\sim 4-6$ with JWST/NIRCam grism spectroscopy
• Evidence for Impact of Galaxy Mergers on Stellar Kinematics of Early-type Galaxies
• Genesis of morpho-kinematic lopsidedness in minor merger of galaxies
• Beyond the stars: Linking H$\alpha$ sizes, kinematics, and star formation in galaxies at $z\approx 4-6$ with JWST grism surveys and $\text{geko}$
• Quantifying galactic morphological transformations in the cluster environment