We combine the semi-analytical structure formation model, SASHIMI, which predicts subhalo populations in collisionless, cold dark matter (CDM), with a parametric model that maps CDM halos to self-interacting dark matter (SIDM) halos. The resulting model, SASHIMI-SIDM, generates SIDM subhalo populations down to sub-galactic mass scales, for an arbitrary input cross section, in minutes. We show that SASHIMI-SIDM agrees with SIDM subhalo populations from high-resolution cosmological zoom-in simulations in resolved regimes. Crucially, we predict that the fraction of core-collapsed subhalos peaks at a mass scale determined by the input SIDM cross section and decreases toward higher halo masses, consistent with the predictions of gravothermal models and cosmological simulations. For the first time, we also show that the core-collapsed fraction decreases toward lower halo masses. While the dependence of the collapse time on mass and concentration implies such behaviour, our semi-analytical approach allows us to quantify and illustrate this trend clearly across the full mass spectrum of subhalos, including for subhalo masses below the resolution limit of any current cosmological SIDM simulation. As a proof of principle, we apply SASHIMI-SIDM to predict the boost to the local dark matter density and annihilation rate from core-collapsed SIDM subhalos, which can be enhanced relative to CDM by an order of magnitude for viable SIDM models. Thus, SASHIMI-SIDM provides an efficient and reliable tool for scanning SIDM parameter space and testing it with astrophysical observations. The code is publicly available at https://github.com/shinichiroando/sashimi-si.
We study evolution of single subhaloes with their masses of $\sim10^9 M_\odot$ in a Milky-Way-sized host halo for self-interacting dark matter (SIDM) models. We perform dark-matter-only N-body simulations of dynamical evolution of individual subhaloes orbiting its host by varying self-scattering cross sections (including a velocity-dependent scenario), subhalo orbits, and internal properties of the subhalo. We calibrate a gravothermal fluid model to predict time evolution in spherical mass density profiles of isolated SIDM haloes with the simulations. We find that tidal effects of SIDM subhalo…
Survival of the most compact: the life and death of satellite halos in self-interacting dark matter
Goethe University（法兰克福歌德大学）；Donostia International Physics Center (DIPC)（圣塞巴斯蒂安国际物理中心）；Ludwig-Maximilians-Universität München（慕尼黑路德维希-马克西米利安大学）；Excellence Cluster ORIGINS（ORIGINS卓越集群）；The University of Texas at Austin（得克萨斯大学奥斯汀分校）；University of California - Irvine（加州大学尔湾分校）
Self-interacting dark matter (SIDM) cosmologies admit an enormous diversity of dark matter (DM) halo density profiles, from 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 $\lesssim 10^8 M_\odot$ subhalos in lens-mass systems ($\sim 10^{13}M_\odot$) is computationally expensive with traditional N-body simulations. In this work, we develop a new hybr…
Warm dark matter (WDM) can potentially explain small-scale observations that currently challenge the cold dark matter (CDM) model, as warm particles suppress structure formation due to free-streaming effects. Observing small-scale matter distribution provides a valuable way to distinguish between CDM and WDM. In this work, we use observations from the Dark Energy Survey and PanSTARRS1, which observe 270 Milky-Way satellites after completeness corrections. We test WDM models by comparing the number of satellites in the Milky Way with predictions derived from the Semi-Analytical SubHalo Inferenc…
Given recent developments in our understanding of the Large Magellanic Cloud's (LMC) impact on the Milky Way's (MW) dark matter subhalo population, we compare the signatures of dark matter and baryonic physics on subhalos in MW systems with realistic LMC analogs. In particular, we study the effects of self-interacting dark matter (SIDM), warm dark matter (WDM), and the Galactic disk on the peak maximum circular velocity ($V_{\mathrm{peak}}$) function, radial distribution, and spatial distribution of MW and LMC-associated subhalos using cosmological dark matter-only zoom-in simulations of MW+LM…
Any successful model of dark matter must explain the diversity of observed Milky Way (MW) satellite density profiles, from very dense ultrafaints to large, low density satellites such as Crater~II that appear to be larger their anticipated host dark matter haloes. We consider cold dark matter (CDM), warm dark matter (WDM, 3.3keV thermal relic power spectrum), and a self-interacting dark matter model (SIDM) that induces gravothermal collapse in low mass subhaloes. Predictions for these density profiles are complicated by the limitations of simulation resolution in the stripping of subhaloes by …
The Sensitivity of Substructure Lensing to SIDM Core-collapse Model Variation
The Ohio State University（俄亥俄州立大学）；University of Minnesota（明尼苏达大学）；Texas A&M University（德克萨斯农工大学）；University of New Mexico（新墨西哥大学）；University of California, Los Angeles（加州大学洛杉矶分校）；Institute for Advanced Study（高等研究院）；Carnegie Science（卡内基科学）
We present results from N-body simulations of self-interacting dark matter (SIDM) subhalos, which could host ultra-faint dwarf spheroidal galaxies, inside a Milky-Way-like main halo. We find that high-concentration subhalos are driven to gravothermal core collapse, while low-concentration subhalos develop large (kpc-sized) low-density cores, with both effects depending sensitively on the satellite's orbit and the self-interaction cross section over mass $σ/m$. The overall effect for $σ/m \gtrsim 3 \ \rm cm^2/g$ is to increase the range of inner densities, potentially explaining the observed di…
Self-interacting dark matter (SIDM) has gathered growing attention as a solution to the small scale problems of the collisionless cold dark matter (DM). We investigate the SIDM using stellar kinematics of 23 ultra-faint dwarf (UFD) galaxies with the phenomenological SIDM halo model. The UFDs are DM-dominated and have less active star formation history. Accordingly, they are the ideal objects to test the SIDM, as their halo profiles are least affected by the baryonic feedback processes. We found no UFDs favor non-zero self-interaction and some provide stringent constraints within the simple SID…
Milky Way (MW) satellites reside within dark matter (DM) subhalos with a broad distribution of circular velocity profiles. This diversity is enhanced with the inclusion of ultra-faint satellites, which seemingly have very high DM densities, albeit with large systematic uncertainties. We argue that if confirmed, this large diversity in the MW satellite population poses a serious test for the structure formation theory with possible implications for the DM nature. For the Cold Dark Matter model, the diversity might be a signature of the combined effects of subhalo tidal disruption by the MW disk…
A dense dark matter core of the subhalo in the strong lensing system JVAS B1938+666
Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台暗物质与空间天文重点实验室）；School of Astronomy and Space Science, University of Science and Technology of China（中国科学技术大学天文与空间科学学院）
We explore the impact of elastic, anisotropic, velocity-dependent dark matter (DM) self-interactions on the host halo and subhalos of Milky Way (MW)--mass systems. We consider a generic self-interacting dark matter (SIDM) model parameterized by the masses of a light mediator and the DM particle. The ratio of these masses, $w$, sets the velocity scale above which momentum transfer due to DM self-interactions becomes inefficient. We perform high-resolution zoom-in simulations of an MW-mass halo for values of $w$ that span scenarios in which self-interactions either between the host and its subha…
Studying the smallest self-bound dark matter structure in our Universe can yield important clues about the fundamental particle nature of dark matter. Galaxy-scale strong gravitational lensing provides a unique way to detect and characterize dark matter substructures at cosmological distances from the Milky Way. Within the cold dark matter (CDM) paradigm, the number of low-mass subhalos within lens galaxies is expected to be large, implying that their contribution to the lensing convergence field is approximately Gaussian and could thus be described by their power spectrum. We develop here a g…
It has been proposed that gravothermal collapse due to dark matter self-interactions (i.e. self-interacting dark matter, SIDM) can explain the observed diversity of the Milky Way (MW) satellites' central dynamical masses. We investigate the process behind this hypothesis using an $N$-body simulation of a MW-analogue halo with velocity dependent self-interacting dark matter (vdSIDM) in which the low velocity self-scattering cross-section, $σ_{T}/m_{x}$, reaches 100 cm$^{2}$g$^{-1}$; we dub this model the vd100 model. We compare the results of this simulation to simulations of the same halo that…
Prompt cusps in hierarchical dark matter halos: Implications for annihilation boost
GRAPPA Institute, University of Amsterdam（GRAPPA研究所，阿姆斯特丹大学）；Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo（东京大学宇宙物理与数学研究所（Kavli））；Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT)（能源、环境与技术研究中心）
JWST lensed quasar dark matter survey V: Hints of self-interacting dark matter from 29 quadruply imaged quasars
University of Chicago（芝加哥大学）；Kavli Institute for Cosmological Physics, University of Chicago（芝加哥大学卡弗里宇宙学物理研究所）；University of California, Merced（加州大学默塞德分校）；Perimeter Institute for Theoretical Physics（理论物理前沿研究所）；Carnegie Observatories（卡内基观测站）；University of California, Los Angeles（加州大学洛杉矶分校）；University of California, Irvine（加州大学尔湾分校）；Universidad Andres Bello（安德烈斯贝略大学）；Millennium Institute of Astrophysics, Chile（智利天体物理千年研究所）；California Polytechnic State University（加州州立理工大学）
We use cosmological simulations to study the effects of self-interacting dark matter (SIDM) on the density profiles and substructure counts of dark matter halos from the scales of spiral galaxies to galaxy clusters, focusing explicitly on models with cross sections over dark matter particle mass σ/m = 1 and 0.1 cm^2/g. Our simulations rely on a new SIDM N-body algorithm that is derived self-consistently from the Boltzmann equation and that reproduces analytic expectations in controlled numerical experiments. We find that well-resolved SIDM halos have constant-density cores, with significantly …
We use high-resolution hydrodynamical simulation to test the difference of halo properties in cold dark matter (CDM) and a self-interacting dark matter (SIDM) scenario with a constant cross-section of $σ^\text{T}/m_χ=1\;\text{cm}^{2}\text{g}^{-1}$. We find that the interplay between dark matter self-interaction and baryonic physics induces a complex evolution of the halo properties, which depends on the halo mass and morphological type, as well as on the halo mass accretion history. While high mass haloes, selected as analogues of early-type galaxies, show cored profiles in the SIDM run, syste…
Core formation and runaway core collapse in models with self-interacting dark matter (SIDM) significantly alter the central density profiles of collapsed halos. Using a forward modeling inference framework with simulated datasets, we demonstrate that flux ratios in quadruple image strong gravitational lenses can detect the unique structural properties of SIDM halos, and statistically constrain the amplitude and velocity dependence of the interaction cross section in halos with masses between $10^6 - 10^{10} M_{\odot}$. Measurements on these scales probe self-interactions at velocities below $3…
Probing Collapsed Dark Matter Halos with Fast Radio Bursts
City University of Hong Kong（香港城市大学）；University of Chinese Academy of Sciences（中国科学院大学）；Tongji University（同济大学）；The Hong Kong University of Science and Technology（香港科技大学）
Wave-Optics Imprints of Warm Dark Matter Subhalos with Prompt Cusps on Strongly Lensed Gravitational Waves
Università degli Studi di Torino（都灵大学）；INFN – Istituto Nazionale di Fisica Nucleare, Sezione di Torino（意大利国家核物理研究所都灵分部）；University of Amsterdam（阿姆斯特丹大学）；Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo（东京大学宇宙物质前沿科学中心）
Gravitational-Wave Image Multiplicity as a Topological Probe of Dark-Matter Core Collapse
School of Physics and Optoelectronic Engineering, Yangtze University（长江大学物理与光电工程学院）；School of Physics and Technology, Wuhan University（武汉大学物理科学与技术学院）；National Centre for Nuclear Research（国家核研究中心）；Department of Basic Courses, Beijing University of Agriculture（北京农学院基础课部）
The BUFFALO Survey : The Subhalo Mass Function for Abell 2744 with Strong+Weak Gravitational Lensing
Durham University（杜伦大学）；University of KwaZulu-Natal（夸祖鲁-纳塔尔大学）；STAR Institute（STAR研究所）；University of Hertfordshire（赫特福德大学）；Carnegie Observatories（卡内基天文台）
We analyze strongly lensed images in 8 galaxy clusters to measure their dark matter density profiles in the radial region between 10 kpc and 150 kpc, and use this to constrain the self-interaction cross section of dark matter (DM) particles. We infer the mass profiles of the central DM halos, bright central galaxies, key member galaxies, and DM subhalos for the member galaxies for all 8 clusters using the Qlens code. The inferred DM halo surface densities are fit to a self-interacting dark matter (SIDM) model, which allows us to constrain the self-interaction cross section over mass $σ$/m. Whe…
Self-Interacting Dark Matter is an attractive alternative to the Cold Dark Matter paradigm only if it is able to substantially reduce the central densities of dwarf-size haloes while keeping the densities and shapes of cluster-size haloes within current constraints. Given the seemingly stringent nature of the latter, it was thought for nearly a decade that SIDM would be viable only if the cross section for self-scattering was strongly velocity-dependent. However, it has recently been suggested that a constant cross section per unit mass of sigma_T/m~0.1cm^2/g is sufficient to accomplish the de…
