Numerical Modelling of the Dynamics of the Galactic Halos in the Colliding Galaxies

Khrapov, S. S.; Хоперсков, А. В.; Корчагин, В. И.

doi:10.14529/mmp190210

Cited by 4 publications

(4 citation statements)

References 33 publications

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“…We used mathematical and corresponding numerical models of the dynamics of multicomponent galaxies, which are described in the works [93][94][95][96]. Gas movement was based on hydrodynamic equations: ∂ϱ ∂t…”

Section: Minor-merger Modelmentioning

confidence: 99%

“…The equation of state of an ideal gas with the adiabatic exponent γ = 5/3 closes the system of Equations ( 1)-(3). We used the SPH method to numerically integrate the Equations ( 1)-(3) [93][94][95][96], which has some advantages for modeling interacting multi-component galaxies. Firstly, it is possible to model both the collisional component (gas) and collisionless subsystems (stars and dark matter) in the same way, which is convenient when calculating the gravitational force.…”

Section: Minor-merger Modelmentioning

confidence: 99%

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Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers

Khoperskov,

Khrapov,

Sirotin

2023

Galaxies

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The dynamics of the merger of a dwarf disc galaxy with a massive spiral galaxy of the Milky Way type were studied in detail. The remnant of such interaction after numerous crossings of the satellite through the disc of the main galaxy was a compact stellar core, the characteristics of which were close to small compact elliptical galaxies (cEs) or large ultra-compact dwarfs (UCDs). Such transitional cE/UCD objects with an effective radius of 100–200 pc arise as a result of stripping the outer layers of the stellar core during the destruction of a dwarf disc galaxy. Numerical models of the satellite before interaction included baryonic matter (stars and gas) and dark mass. We used N-body to describe the dynamics of stars and dark matter, and we used smoothed-particle hydrodynamics to model the gas components of both galaxies. The direct method of calculating the gravitational force between all particles provided a qualitative resolution of spatial structures up to 10 pc. The dwarf galaxy fell onto the gas and stellar discs of the main galaxy almost along a radial trajectory with a large eccentricity. This ensured that the dwarf crossed the disc of the main galaxy at each pericentric approach over a time interval of more than 9 billion years. We varied the gas mass and the initial orbital characteristics of the satellite over a wide range, studying the features of mass loss in the core. The presence of the initial gas component in a dwarf galaxy significantly affects the nature of the formation and evolution of the compact stellar core. The gas-rich satellite gives birth to a more compact elliptical galaxy compared to the merging gas-free dwarf galaxy. The initial gas content in the satellite also affects the internal rotation in the stripped nucleus. The simulated cE/UCD galaxies contained very little gas and dark matter at the end of their evolution.

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Section: Minor-merger Modelmentioning

confidence: 99%

Section: Minor-merger Modelmentioning

confidence: 99%

Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers

Khoperskov,

Khrapov,

Sirotin

2023

Galaxies

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“…The gravitational force is calculated by the direct Particle-Particle method of summing the gravitational interaction of each particle with all the other stellar and gaseous particles: (5) where is a distance between two particles, is a cutoff radius, which ensures the collisionless for the stellar component and reduce a strong pairwise gravitational interactions of close gas particles. A self-consistent modeling of dynamics of collisionless and gaseous particles using a parallel CUDS algorithm "N-body + SPH" was described by [28]. The application of this code for dynamical modeling of stellar/gaseous disc of the Milky Way may be found in [29].…”

Section: Numerical Implementation Of Modelsmentioning

confidence: 99%

On the Formation of Spiral Arms in Dwarf Galaxies

et al. 2021

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Spiral structure (both flocculent and Grand Design types) is very rarely observed in dwarf galaxies because the formation of spiral arms requires special conditions. In this work we analyze the sample of about 40 dS-galaxies found by scanning by eye the images of late-type galaxies with and and photometric diameter kpc. We found that apart from the lower average gas (HI) fraction the other properties of dS-galaxies including the presence of a bar and the isolation index do not differ much from those for dwarf Irr or Sm-types of similar luminosity and rotation velocity (or specific angular momentum).There are practically no dS-galaxies with rotation velocity below 50-60 km s -1 . To check the conditions of formation of spiral structure in dwarf galaxies we carried out a series of N-body/hydrodynamic simulations of lowmass stellar-gaseous discy galaxies by varying the model kinematic parameters of discs, their initial thickness, relative masses and scale lengths of stellar and gaseous disc components, and stellar-to-dark halo masses. We came to conclusion that the gravitational mechanism of spiral structure formation is effective only for thin stellar discs, which are non-typical for dwarf galaxies, and for not too slowly rotating galaxies. Therefore, only a small fraction of dwarf galaxies with stellar/gaseous discs have spiral or ring structures. The thicker stellar disc, the more gas is required for the spiral structure to form. The reduced gas content in many dS-galaxies compared to non-spiral ones may be a result of more efficient star formation due to a higher volume gas density thank to the thinner stellar/gaseous discs.

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“…where 𝑟 𝑖 𝑗 is a distance between two particles, 𝑟 𝑐 is a cut-off radius, which ensures the collisionless for the stellar component and reduce a strong pairwise gravitational interactions of close gas particles. A self-consistent modeling of dynamics of collisionless and gaseous particles using a parallel CUDS algorithm "N-body+SPH" was described by Khrapov et al (2019). The application of this code for dynamical modeling of stellar/gaseous disc of the Milky Way may be found in Khoperskov et al (2020).…”

Section: Numerical Implementation Of Modelsmentioning

confidence: 99%

On the formation of spiral arms in dwarf galaxies

Zasov,

Khoperskov,

Zaitseva

et al. 2021

Preprint

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Spiral structure (both flocculent and Grand Design types) is very rarely observed in dwarf galaxies because the formation of spiral arms requires special conditions. In this work we analyze the sample of about 40 dS-galaxies found by scanning by eye the images of late-type galaxies with 𝑚 𝐵 < 15 𝑚 and 𝑀 𝐵 > −18 𝑚 and photometric diameter 𝐷 25 < 12 kpc. We found that apart from the lower average gas (HI) fraction the other properties of dS-galaxies including the presence of a bar and the isolation index do not differ much from those for dwarf Irr or Sm-types of similar luminosity and rotation velocity (or specific angular momentum).There are practically no dS-galaxies with rotation velocity below 50 -60 km sec −1 .To check the conditions of formation of spiral structure in dwarf galaxies we carried out a series of N-body/hydrodynamic simulations of low-mass stellar-gaseous discy galaxies by varying the model kinematic parameters of discs, their initial thickness, relative masses and scale lengths of stellar and gaseous disc components, and stellar-to-dark halo masses. We came to conclusion that the gravitational mechanism of spiral structure formation is effective only for thin stellar discs, which are non-typical for dwarf galaxies, and for not too slowly rotating galaxies. Therefore, only a small fraction of dwarf galaxies with stellar/gaseous discs have spiral or ring structures. The thicker stellar disc, the more gas is required for the spiral structure to form. The reduced gas content in many dS-galaxies compared to non-spiral ones may be a result of more efficient star formation due to a higher volume gas density thank to the thinner stellar/gaseous discs.

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Numerical Modelling of the Dynamics of the Galactic Halos in the Colliding Galaxies

Cited by 4 publications

References 33 publications

Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers

Formation of Transitional cE/UCD Galaxies through Massive/Dwarf Disc Galaxy Mergers

On the Formation of Spiral Arms in Dwarf Galaxies

On the formation of spiral arms in dwarf galaxies

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