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We benchmark the semi-analytical isothermal Jeans model against a high-resolution isolated N-body simulation that follows a self-interacting dark matter (SIDM) halo into deep core collapse. The model accurately reproduces the density…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-03 Shubo Li , Moritz S. Fischer , Zixiang Jia , Fangzhou Jiang , Ran Li , Hai-Bo Yu

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…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-28 Shin'ichiro Ando , Shunichi Horigome , Ethan O. Nadler , Daneng Yang , Hai-Bo Yu

While cosmological dark matter-only simulations relying solely on gravitational effects are comparably fast to compute, baryonic properties in simulated galaxies require complex hydrodynamic simulations that are computationally costly to…

Astrophysics of Galaxies · Physics 2022-11-16 Ben Moews , Romeel Davé , Sourav Mitra , Sultan Hassan , Weiguang Cui

Recent focus on the importance of cold, unshocked gas accretion in galaxy formation -- not explicitly included in semi-analytic studies -- motivates the following detailed comparison between two inherently different modelling techniques:…

Astrophysics of Galaxies · Physics 2015-05-14 M. J. Stringer , A. M. Brooks , A. J. Benson , F. Governato

Semiparametric forecasting and filtering are introduced as a method of addressing model errors arising from unresolved physical phenomena. While traditional parametric models are able to learn high-dimensional systems from small data sets,…

Methodology · Statistics 2016-02-17 Tyrus Berry , John Harlim

We study the impact of numerical parameters on the properties of cold dark matter haloes formed in collisionless cosmological simulations. We quantify convergence in the median spherically-averaged circular velocity profiles for haloes of…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-12 Aaron D. Ludlow , Joop Schaye , Richard Bower

Gas-poor galaxies can be modelled as composite collisionless stellar systems, with a dark matter halo and one or more stellar components, representing different stellar populations. The dynamical evolution of such composite systems is often…

Astrophysics of Galaxies · Physics 2021-03-24 Carlo Nipoti , Giacomo Cherchi , Giuliano Iorio , Francesco Calura

Dark matter subhaloes are key for the predictions of simulations of structure formation, but their existence frequently ends prematurely due to two technical issues, namely numerical disruption in N-body simulations and halo finders failing…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-03 Benedikt Diemer , Peter Behroozi , Philip Mansfield

N-body dark matter simulations of structure formation in the $\Lambda$CDM model predict a population of subhalos within Galactic halos that have higher central densities than inferred for satellites of the Milky Way, a tension known as the…

We model the acquisition of spin by dark-matter halos in semi-analytic merger trees. We explore two different algorithms; one in which halo spin is acquired from the orbital angular momentum of merging satellites, and another in which halo…

Astrophysics · Physics 2009-11-06 Ariyeh H. Maller , Avishai Dekel , Rachel S. Somerville

We compare predictions of cooled masses and cooling rates from three stripped-down Semi-Analytic Models (SAMs) of galaxy formation with the results of N-body+SPH simulations with gas particle mass of 3.9x10^6 Msun, where radiative cooling…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Pierluigi Monaco , Andrew Benson , Gabriella De Lucia , Fabio Fontanot , Stefano Borgani , Michael Boylan-Kolchin

Semi-analytic models are a powerful tool for studying the formation of galaxies. However, these models inevitably involve a significant number of poorly constrained parameters that must be adjusted to provide an acceptable match to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 R. G. Bower , I. Vernon , M. Goldstein , A. J. Benson , C. G. Lacey , C. M. Baugh , S. Cole , C. S. Frenk , .

We introduce a new Markov Chain Monte Carlo (MCMC) algorithm with parallel tempering for fitting theoretical models of horizon-scale images of black holes to the interferometric data from the Event Horizon Telescope (EHT). The algorithm…

Instrumentation and Methods for Astrophysics · Physics 2020-05-20 Dimitrios Psaltis , Feryal Ozel , Lia Medeiros , Pierre Christian , Junhan Kim , Chi-kwan Chan , Landen J. Conway , Carolyn A. Raithel , Dan Marrone , Tod R. Lauer

We present a new technique for creating mock catalogues of the individual stars that make up the accreted component of stellar haloes in cosmological simulations and show how the catalogues can be used to test and interpret observational…

Astrophysics of Galaxies · Physics 2014-11-27 Ben Lowing , Wenting Wang , Andrew Cooper , Rachel Kennedy , John Helly , Carlos Frenk , Shaun Cole

Next generation galaxy surveys demand the development of massive ensembles of galaxy mocks to model the observables and their covariances, what is computationally prohibitive using $N$-body simulations. COLA is a novel method designed to…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-07 Albert Izard , Martin Crocce , Pablo Fosalba

The density profiles of dark matter haloes can potentially probe dynamics, fundamental physics, and cosmology, but some of the most promising signals reside near or beyond the virial radius. While these scales have recently become…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-29 Benedikt Diemer

Galaxy formation and evolution models, such as semi-analytic models, are powerful theoretical tools for predicting how galaxies evolve across cosmic time. These models follow the evolution of galaxies based on the halo assembly histories…

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…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-09 Mark R. Lovell , Jesús Zavala

We present a generalization of our recently proposed machine learning framework, aiming to provide new physical insights into dark matter halo formation. We investigate the impact of the initial density and tidal shear fields on the…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-20 Luisa Lucie-Smith , Hiranya V. Peiris , Andrew Pontzen

To maximize the amount of information extracted from cosmological datasets, simulations that accurately represent these observations are necessary. However, traditional simulations that evolve particles under gravity by estimating…