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We predict the properties of stellar halos in galaxies of present-day virial mass $10^8 < M_{200} < 10^{12} {\rm M_\odot}$ by combining the GALFORM semi-analytic model of galaxy formation, the COCO cosmological N-body simulation, and the…

Astrophysics of Galaxies · Physics 2025-06-23 Andrew P. Cooper , Carlos S. Frenk , Wojciech A. Hellwing , Sownak Bose

We use the halo occupation model to calibrate galaxy group finders in magnitude-limited redshift surveys. Since, according to the current scenario of structure formation, galaxy groups are associated with cold dark matter halos, we make use…

Astrophysics · Physics 2009-11-10 Xiaohu Yang , H. J. Mo , Frank C. van den Bosch , Y. P. Jing

[abridged] We present a detailed comparison of fundamental dark matter halo properties retrieved by a substantial number of different halo finders. These codes span a wide range of techniques including friends-of-friends (FOF),…

We present a deep-learning-based approach for identifying dark matter haloes in cosmological N-body simulations. Our framework consists of a volumetric Convolutional Neural Network to classify individual simulation particles as either halo…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-26 Soumadeep Maiti , Carlos M. Correa , Andrea Fiorilli , Andrés N. Ruiz , Dante J. Paz , Alejandro Pérez Fernández , Ariel G. Sánchez

We study galaxy clustering using halo models, where gravitational clustering is described in terms of dark matter halos. At small scales, clustering statistics are dominated by halo density profiles, whereas at large scales, correlations…

Astrophysics · Physics 2009-10-31 Roman Scoccimarro , Ravi K. Sheth , Lam Hui , Bhuvnesh Jain

We present a new algorithm for identifying superbubbles in HI column density maps of both observed and simulated galaxies that has only a single adjustable parameter. The algorithm includes an automated galaxy-background separation step to…

Astrophysics of Galaxies · Physics 2024-09-19 Brock Wallin , Benjamin D. Wibking , G. Mark Voit

We investigate mass segregation in group and cluster environments by identifying galaxy analogues in high-resolution dark matter simulations. Subhalos identified by the AHF and ROCKSTAR halo finders have similar mass functions, independent…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Gandhali D. Joshi , Laura C. Parker , James Wadsley

The ever increasing size and complexity of data coming from simulations of cosmic structure formation demands equally sophisticated tools for their analysis. During the past decade, the art of object finding in these simulations has hence…

We build upon Ordering Points To Identify Clustering Structure (OPTICS), a hierarchical clustering algorithm well-known to be a robust data-miner, in order to produce Halo-OPTICS, an algorithm designed for the automatic detection and…

Astrophysics of Galaxies · Physics 2021-01-06 William H. Oliver , Pascal J. Elahi , Geraint F. Lewis , Chris Power

We present the GalMer database, a library of galaxy merger simulations, made available to users through tools compatible with the Virtual Observatory (VO) standards adapted specially for this theoretical database. To investigate the physics…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 Igor Chilingarian , Paola Di Matteo , Francoise Combes , Anne-Laure Melchior , Benoit Semelin

Intrinsic alignments of galaxies are a significant astrophysical systematic affecting cosmological constraints from weak gravitational lensing. Obtaining numerical predictions from hydrodynamical simulations of expected survey volumes is…

Generating mocks for future sky surveys requires large volumes and high resolutions, which is computationally expensive even for fast simulations. In this work we try to develop numerical schemes to calibrate various halo and matter…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-15 Biwei Dai , Yu Feng , Uros Seljak , Sukhdeep Singh

Simulating the distribution of cosmological neutral hydrogen (HI) during the epoch of reionization requires a high dynamic range and is hence computationally expensive. The size of the simulation is dictated by the largest scales one aims…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-24 Ankur Barsode , Tirthankar Roy Choudhury

We apply machine learning, a powerful method for uncovering complex correlations in high-dimensional data, to the galaxy-halo connection of cosmological hydrodynamical simulations. The mapping between galaxy and halo variables is stochastic…

Astrophysics of Galaxies · Physics 2022-06-16 Richard Stiskalek , Deaglan J. Bartlett , Harry Desmond , Dhayaa Anbajagane

Cosmological galaxy formation simulations are still limited by their spatial/mass resolution and cannot model from first principles some of the processes, like star formation, that are key in driving galaxy evolution. As a consequence they…

Astrophysics of Galaxies · Physics 2022-03-02 Andrea V. Macciò , Mohamad Ali-Dib , Pavle Vulanović , Hind Al Noori , Fabian Walter , Nico Krieger , Tobias Buck

The structural and dynamic properties of the dark matter halos, though an important ingredient in understanding large-scale structure formation, require more conservative particle resolution than those required by halo mass alone in a…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 Sujatha Ramakrishnan , Premvijay Velmani

Wide-field cosmological surveys provide hundreds of thousands of spectroscopically confirmed galaxy groups and clusters, valuable for tracing baryonic matter distribution. However, controlling systematics in identifying host dark matter…

Cosmological N-body simulations are crucial for understanding how the Universe evolves. Studying large-scale distributions of matter in these simulations and comparing them to observations usually involves detecting dense clusters of…

Astrophysics of Galaxies · Physics 2019-12-25 Aidan Reilly , Nikita Ivkin , Gerard Lemson , Vladimir Braverman , Alexander Szalay

We present a new algorithm for identifying dark matter halos, substructure, and tidal features. The approach is based on adaptive hierarchical refinement of friends-of-friends groups in six phase-space dimensions and one time dimension,…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-15 Peter S. Behroozi , Risa H. Wechsler , Hao-Yi Wu