Dark matter annihilation feedback in cosmological simulations – I: Code convergence and idealized haloes

Iwanus, Nikolas; Elahi, Pascal J.; Lewis, Geraint F.

doi:10.1093/mnras/stx1974

Cited by 10 publications

(15 citation statements)

References 78 publications

(80 reference statements)

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“…Figure 8 shows a volume rendered representation (see Gárate 2017) of the DM density ρ χ , gas density ρ g , and specific internal energy of the gas u g . It is evident that the strong DMAF in this simulation suppresses the formation of substructure, and the gas density distribution is much more washed out than in the fiducial ΛCDM simulation, as reported in Iwanus et al (2017Iwanus et al ( , 2019.…”

Section: Parametermentioning

confidence: 49%

“…with Hubble constant H 0 , critical density ρ crit , and u 0 = u(z 0 ) (see Iwanus et al (2017)). Note that a and z are related by 1 + z = a −1 .…”

Section: Discussionmentioning

confidence: 99%

“…We take N ngb = 40, and the gravitational softening length is r soft = 4 kpc. The gravitational softening length plays an important role since it is related to the relative error in the DMAF energy rate due to an unresolved NFW cusp, as derived in Iwanus et al (2017). Figure 6 shows the gas density ρ g and the temperature T g of the gas within a radius of 50 kpc around the halo centre, averaged over the z-coordinate (created with the package Pynbody (Pontzen et al 2013)).…”

Section: Isolated Galaxymentioning

confidence: 99%

“…A model for DM decay into dark radiation is considered in Tram et al (2019). This work builds on Iwanus et al (2017), where a method for DMAF into SM particles was presented that self-consistently incorporates the DMAF power generated by the DM particles in the course of the cosmological simulation instead of resorting to an analytic model. Whereas the authors of that work propose to calculate the DMAF power at each gas N-body particle, we present a new method herein in which the DMAF power is determined at each DM N-body particle and then injected into the surrounding gas.…”

Section: Introductionmentioning

confidence: 99%

“…Then, we introduce our numerical method in Section 3, focusing on different injection schemes and on the individual time step scheme. Section 4 is dedicated to a juxtaposition between our method and the receiver-based method proposed in Iwanus et al (2017). Numerical results are presented in Section 5, and we conclude the paper in Section 6.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A novel scheme for Dark Matter Annihilation Feedback in cosmological simulations

List

Iwanus

Elahi

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present a new self-consistent method for incorporating dark matter annihilation feedback (DMAF) in cosmological N-body simulations. The power generated by DMAF is evaluated at each dark matter (DM) particle which allows for flexible energy injection into the surrounding gas based on the specific DM annihilation model under consideration. Adaptive, individual time steps for gas and DM particles are supported and a new time-step limiter, derived from the propagation of a Sedov-Taylor blast wave, is introduced. We compare this donor-based approach with a receiver-based approach used in recent studies and illustrate the differences by means of a toy example. Furthermore, we consider an isolated halo and a cosmological simulation and show that for these realistic cases, both methods agree well with each other. The extension of our implementation to scenarios such as non-local energy injection, velocity-dependent annihilation cross-sections, and DM decay is straightforward.

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Section: Parametermentioning

confidence: 49%

“…with Hubble constant H 0 , critical density ρ crit , and u 0 = u(z 0 ) (see Iwanus et al (2017)). Note that a and z are related by 1 + z = a −1 .…”

Section: Discussionmentioning

confidence: 99%

Section: Isolated Galaxymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A novel scheme for Dark Matter Annihilation Feedback in cosmological simulations

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Iwanus

Elahi

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Late-time dark matter oscillations and the core-cusp problem

Cline

Gambini

McDermott

et al. 2021

J. High Energ. Phys.

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The core-cusp problem persists as an unresolved tension between the pre- dictions of ΛCDM cosmology and observations of dark matter (DM) profiles in dwarf spheroidal and other galaxies. We present a novel scenario for converting cusps into cores through reactivation of DM annihilation in galaxies at late times. This can happen in asymmetric DM models when there is a very small DM-number violating mass term that causes oscillations between DM and its antiparticle. Using analytic methods as well as gravitational N-body simulations, we show that this mechanism can robustly eliminate cusps from galactic DM profiles for light fermionic DM of mass mχ ∼ (0.1 − 1) GeV and a lighter mediator into which the DM can annihilate. We identify regions of parameter space where annihilation of DM particles is more efficient than elastic scattering at reducing the inner density of the DM profile. Dark matter annihilation is therefore a qualitatively distinct alternative to the mechanism of elastic self-interacting dark matter for addressing the cusp-core problem.

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Large-scale dark matter simulations

Angulo

Hahn

2022

Living Rev Comput Astrophys

111

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We review the field of collisionless numerical simulations for the large-scale structure of the Universe. We start by providing the main set of equations solved by these simulations and their connection with General Relativity. We then recap the relevant numerical approaches: discretization of the phase-space distribution (focusing on N-body but including alternatives, e.g., Lagrangian submanifold and Schrödinger–Poisson) and the respective techniques for their time evolution and force calculation (direct summation, mesh techniques, and hierarchical tree methods). We pay attention to the creation of initial conditions and the connection with Lagrangian Perturbation Theory. We then discuss the possible alternatives in terms of the micro-physical properties of dark matter (e.g., neutralinos, warm dark matter, QCD axions, Bose–Einstein condensates, and primordial black holes), and extensions to account for multiple fluids (baryons and neutrinos), primordial non-Gaussianity and modified gravity. We continue by discussing challenges involved in achieving highly accurate predictions. A key aspect of cosmological simulations is the connection to cosmological observables, we discuss various techniques in this regard: structure finding, galaxy formation and baryonic modelling, the creation of emulators and light-cones, and the role of machine learning. We finalise with a recount of state-of-the-art large-scale simulations and conclude with an outlook for the next decade.

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Dark matter annihilation feedback in cosmological simulations – I: Code convergence and idealized haloes

Cited by 10 publications

References 78 publications

A novel scheme for Dark Matter Annihilation Feedback in cosmological simulations

A novel scheme for Dark Matter Annihilation Feedback in cosmological simulations

Late-time dark matter oscillations and the core-cusp problem

Large-scale dark matter simulations

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