Dissipative dark matter on FIRE – I. Structural and kinematic properties of dwarf galaxies

Shen, Xuejian; Hopkins, Philip F.; Necib, Lina; Jiang, Fangzhou; Boylan-Kolchin, Michael; Wetzel, Andrew

doi:10.1093/mnras/stab2042

Cited by 32 publications

(23 citation statements)

References 169 publications

(220 reference statements)

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“…The shapes of the gas (and dark matter) distributions are sensitive to the degree of the central concentration of the total mass. As intracluster gas cools and flows towards the halo center, the distribution becomes more spherical (e.g., Dubinski 1994;Evrard et al 1994;Tissera & Dominguez-Tenreiro 1998;Kazantzidis et al 2004;Debattista et al 2008;Suto et al 2017;Shen et al 2021). In this study, the "peaky" clusters have lower isophote ellipticities than the "non-peaky" clusters, which is consistent with this picture.…”

Section: Impact Of Baryonic Physicssupporting

confidence: 84%

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X-ray morphology of cluster-mass haloes in self-interacting dark matter

Shen¹,

Brinckmann²,

Rapetti³

et al. 2022

Preprint

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We perform cosmological zoom-in simulations of 19 relaxed cluster-mass haloes with the inclusion of adiabatic gas within the cold dark matter (CDM) and self-interacting dark matter (SIDM) models. These clusters are selected as dynamically relaxed clusters from a parent simulation and have typical masses of 𝑀 200 1 -3 × 10 15 M . We find that both the dark matter and the intracluster gas distributions in SIDM are more spherical than their CDM counterparts, although the difference is smaller for the gas. Mock X-ray images are generated based on the simulations and are compared to the real X-ray images of 84 relaxed clusters selected from the Chandra and ROSAT archives. We perform ellipse fitting for the isophotes of mock and real X-ray images and obtain the ellipticities at cluster-centric radii of 𝑟 0.1 -0.2 𝑅 200 . The X-ray isophotes in SIDM models with increasing cross-sections are rounder than their CDM counterparts, which manifests as a systematic shift in the distribution function of ellipticities. Unexpectedly, the X-ray morphology of the observed "non-peaky" (non-cool-core) clusters agrees better with SIDM models with cross-section per unit mass (𝜎/𝑚) = 0.5 -1 cm 2 g −1 than CDM and SIDM with (𝜎/𝑚) = 0.1 cm 2 g −1 . Our statistical analysis indicates that the latter two models are disfavored at least at the 68% confidence level. This conclusion is not altered by shifting the radial range of measurements or applying temperature selection criterion. However, the primary uncertainty originates from the lack of baryonic physics in the adiabatic model, such as gas cooling, star formation and feedback effects, which have the potential to reconcile CDM simulations with observations.

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Section: Impact Of Baryonic Physicssupporting

confidence: 84%

“…Cosmological structure formation in SIDM has been investigated extensively since the first SIDM simulations in the early 2000's (Yoshida et al 2000;Davé et al 2001;Colín et al 2002). The thermal-averaged local collision rate of dark matter is (e.g., Tulin & Yu 2018;Shen et al 2021)…”

Section: Introductionmentioning

confidence: 99%

X-ray morphology of cluster-mass haloes in self-interacting dark matter

Shen¹,

Brinckmann²,

Rapetti³

et al. 2022

Preprint

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“…Therefore, SIDM models with velocity-dependent cross sections have been suggested, with both theoretical motivation from particle physics in the context of hidden-sector models (Feng et al 2009;Tulin et al 2013c,a;Boddy et al 2014;Cline et al 2014;Cyr-Racine et al 2016;Tulin & Yu 2018), and simulation efforts on cluster and galaxy scales (Vogelsberger et al 2012;Zavala et al 2013;Nadler et al 2020b;Banerjee et al 2020;Turner et al 2021;Correa 2021). Other variants of SIDM that have more degrees of freedom are being studied, such as energy dissipation during the dark matter two-body scattering (Schutz & Slatyer 2015;Essig et al 2019;Vogelsberger et al 2019;Huo et al 2020;Shen et al 2021;Chua et al 2021), anisotropic scattering (Kahlhoefer et al 2014;Robertson et al 2017b), and multi-state scattering (Vogelsberger et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Core-collapse, evaporation and tidal effects: the life story of a self-interacting dark matter subhalo

Zeng,

Peter,

et al. 2021

Preprint

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Recently, work on self-interacting dark matter (SIDM) cosmologies has shown that an enormous diversity of dark matter (DM) halo density profiles is possible for a fixed SIDM model, ranging from the development of low-density cores to high-density core-collapsed cusps. The possibility of the growth of high central density in low-mass halos, accelerated if halos are subhalos of larger systems, has intriguing consequences for small-halo searches with substructure lensing. However, following the evolution of 10 8 𝑀 subhalos in lens-mass systems (∼ 10 13 𝑀 ) is computationally expensive with traditional N-body simulations. In this work, we develop a new hybrid semi-analytical + N-body method to study the evolution of SIDM subhalos with high fidelity, from core formation to core-collapse, in staged simulations. With this method, we are able to capture the evaporation of subhalo particles by interactions with host halo particles, an effect that has not yet been fully explored in the context of subhalo core-collapse. We find three main processes driving subhalo evolution: subhalo internal heat outflow, host-subhalo evaporation, and tidal effects. We conclude that the subhalo central density grows only when the heat outflow outweighs the energy gain from evaporation and tidal heating. Thus, evaporation delays or even disrupts subhalo core-collapse. We map out the parameter space for subhalos to core-collapse, and find that it is nearly impossible to drive core collapse in subhalos in SIDM models with constant cross sections. Any discovery of ultracompact dark substructures with future substructure lensing observations disfavors SIDM models with constant cross sections, indicating instead the presence of additional degrees of freedom, such as velocity-dependence or dissipation of energy.

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“…In addition, there are many studies on structure formation in rSIDM using cosmological simulations (e.g. Vogelsberger et al 2012;Vogelsberger & Zavala 2013;Rocha et al 2013;Peter et al 2013;Vogelsberger et al 2014;Despali et al 2019;Banerjee et al 2020;Nadler et al 2020;Robertson et al 2020;Vega-Ferrero et al 2020;Shen et al 2021;Sameie et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Unequal-mass mergers of dark matter haloes with rare and frequent self-interactions

Fischer

Brüggen

Schmidt-Hoberg

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Dark matter self-interactions have been proposed to solve problems on small length scales within the standard cold dark matter cosmology. Here we investigate the effects of dark matter self-interactions in merging systems of galaxies and galaxy clusters with equal and unequal mass ratios. We perform N-body dark matter-only simulations of idealised setups to study the effects of dark matter self-interactions that are elastic and velocity-independent. We go beyond the commonly adopted assumption of large-angle (rare) dark matter scatterings, paying attention to the impact of small-angle (frequent) scatterings on astrophysical observables and related quantities. Specifically, we focus on dark matter-galaxy offsets, galaxy-galaxy distances, halo shapes, morphology and the phase-space distribution. Moreover, we compare two methods to identify peaks: one based on the gravitational potential and one based on isodensity contours. We find that the results are sensitive to the peak finding method, which poses a challenge for the analysis of merging systems in simulations and observations, especially for minor mergers. Large dark matter-galaxy offsets can occur in minor mergers, especially with frequent self-interactions. The subhalo tends to dissolve quickly for these cases. While clusters in late merger phases lead to potentially large differences between rare and frequent scatterings, we believe that these differences are non-trivial to extract from observations. We therefore study the galaxy/star populations which remain distinct even after the dark matter haloes have coalesced. We find that these collisionless tracers behave differently for rare and frequent scatterings, potentially giving a handle to learn about the micro-physics of dark matter.

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Dissipative dark matter on FIRE – I. Structural and kinematic properties of dwarf galaxies

Cited by 32 publications

References 169 publications

X-ray morphology of cluster-mass haloes in self-interacting dark matter

X-ray morphology of cluster-mass haloes in self-interacting dark matter

Core-collapse, evaporation and tidal effects: the life story of a self-interacting dark matter subhalo

Unequal-mass mergers of dark matter haloes with rare and frequent self-interactions

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