Multi-scale and multi-domain computational astrophysics

Elteren, A. van; Pelupessy, Inti; Zwart, Simon Portegies

doi:10.1098/rsta.2013.0385

Cited by 9 publications

(5 citation statements)

References 22 publications

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“…In order to simulate an interaction of PBHs and surrounding dark matter we use a direct summation N-body 4-th order Hermite code ph4 which is a part of Amuse suite [36,37]. This code is MPI-parallel and we made it also OpenMP parallel.…”

Section: A Simulation Code and Initial Conditionsmentioning

confidence: 99%

The evolution of a primordial binary black hole due to interaction with cold dark matter and the formation rate of gravitational wave events

Pilipenko,

Tkachev,

Ivanov

2022

Preprint

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In this Paper we consider a problem of formation and evolution of orbital parameters of a binary primordial black hole (PBH) due to gravitational interaction with clustering cold dark matter (CDM). Mass and initial separation have values, which are appropriate for the problem of explanation of the LIGO/Virgo events by coalescing binary PBHs. We consider both radiation dominated and CDM dominated stages of the evolution using numerical and semi-analytical means. We show that at the end time of our numerical simulations binary's semimajor axis decreases by approximately one hundred times, while its angular momentum decreases by ten times, in comparison to the standard values, which do not take into account effects associated with CDM clustering. We check that our conclusions are hardly affected by numerical artefacts. We estimate the merger rate of binary PBHs due to emission of gravitational wave at the present time both in the standard case when the effects associated with clustering are neglected and in the case when they are taken into account and show, that these effects could increase the merger rate at least by 6 − 8 times in comparison to the standard estimate. This, in turn, means, that a mass fraction of PBHs, f , should be smaller than it was assumed before.

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Section: A Simulation Code and Initial Conditionsmentioning

confidence: 99%

The evolution of a primordial binary black hole due to interaction with cold dark matter and the formation rate of gravitational wave events

Pilipenko,

Tkachev,

Ivanov

2022

Preprint

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“…A focus on MP + MS can be found in Vangheluwe et al 31 They list levels of abstraction, which overlap with multiscale modeling, alongside multi-formalism modeling and meta-modeling as key research directions in multi-paradigm modeling. The close relationships among the three aspects of modeling are evident in titles such as ''Multi-scale and multi-domain computational astrophysics,'' 33 ''Multi-paradigm multi-scale simulations for fuel cell catalysts and membranes,'' 34 and ''Multiscale coupling and multiphysics approaches in earth sciences.'' 35 Collaborative modeling can be promoted by supporting the integration of models that differ in domain, paradigm, and/or scale.…”

Section: Collaborative Multiscale Modelingmentioning

confidence: 99%

Multiscale representation of simulated time

et al. 2017

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To better support multiscale modeling and simulation, we present a multiscale time representation consisting of data types, data structures, and algorithms that collectively support the recording of past events and scheduling of future events in a discrete event simulation. Our approach addresses the drawbacks of conventional time representations: limited range in the case of 32-or 64-bit fixed-point time values; problematic rounding errors in the case of floating-point numbers; and the lack of a universally acceptable precision level in the case of brute force approaches. The proposed representation provides both extensive range and fine resolution in the timing of events, yet it stores and manipulates the majority of event times as standard 64-bit numbers. When adopted for simulation purposes, the representation allows a domain expert to choose a precision level for his/her model. This time precision is honored by the simulator even when the model is integrated with other models of vastly different time scales. Making use of C++11 programming language features and the Discrete Event System Specification formalism, we implemented a simulator to test the time representation and inform a discussion on its implications for collaborative multiscale modeling efforts.

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“…For all these simulations, the astrophysical multipurpose software environment (amuse 1 ; Portegies Zwart et al 2013;Pelupessy et al 2013;van Elteren et al 2014;Portegies Zwart & McMillan 2018;Portegies Zwart et al 2018) can be useful. It provides a uniform interface for many types of simulations with a large and growing set of simulation codes.…”

Section: Introductionmentioning

confidence: 99%

Simulating stellar winds in AMUSE

Helm

Saladino

Zwart

et al. 2019

A&A

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Aims. We present stellar wind.py, a module that provides multiple methods of simulating stellar winds using smoothed particle hydrodynamics codes (SPH) within the astrophysical multipurpose software environment (amuse) framework. Methods. The module currently includes three ways of simulating stellar winds: With the simple wind mode, we create SPH wind particles in a spherically symmetric shell for which the inner boundary is located at the radius of the star. We inject the wind particles with a velocity equal to their terminal velocity. The accelerating wind mode is similar, but with this method particles can be injected with a lower initial velocity than the terminal velocity and they are accelerated away from the star according to an acceleration function. With the heating wind mode, SPH particles are created with zero initial velocity with respect to the star, but instead wind particles are given an internal energy based on the integrated mechanical luminosity of the star. This mode is designed to be used on longer timescales and larger spatial scales compared to the other two modes and assumes that the star is embedded in a gas cloud. Results. We present a number of tests and compare the results and performance of the different methods. For fast winds, we find that both the simple and accelerating mode can reproduce the desired velocity, density and temperature profiles. For slow winds, the simple wind mode is insufficient due to dominant hydrodynamical effects that change the wind velocities. The accelerating mode, with additional options to account for these hydrodynamical effects, can still reproduce the desired wind profiles. We test the heating mode by simulating both a normal wind and a supernova explosion of a single star in a uniform density medium. The stellar wind simulation results matches the analytical solution for an expanding wind bubble. The supernova simulation gives qualitatively correct results, but the simulated bubble expands faster than the analytical solution predicts. We conclude with an example of a triple star system which includes the colliding winds of all three stars.Edwin van der Helm et al.: Simulating stellar winds in AMUSE Section 4 with an exposition of some ongoing research projects using this code and ideas for further use.

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Multi-scale and multi-domain computational astrophysics

Cited by 9 publications

References 22 publications

The evolution of a primordial binary black hole due to interaction with cold dark matter and the formation rate of gravitational wave events

The evolution of a primordial binary black hole due to interaction with cold dark matter and the formation rate of gravitational wave events

Multiscale representation of simulated time

Simulating stellar winds in AMUSE

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