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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 introduce a new halo/subhalo finder, HIKER (a Halo fInder based on KERnel-shift algorithm), which takes advantage of a machine learning method -- the mean-shift algorithm combined with the Plummer kernel function, to effectively locate…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 Shuangpeng Sun , Shihong Liao , Qi Guo , Qiao Wang , Liang Gao

The continuous wavelet transform (CWT) is very useful for processing signals with intricate and irregular structures in astrophysics and cosmology. It is crucial to propose precise and fast algorithms for the CWT. In this work, we review…

Instrumentation and Methods for Astrophysics · Physics 2024-08-28 Yun Wang , Ping He

A new multi-dimensional Hierarchical Structure Finder (HSF) to study the phase-space structure of dark matter in N-body cosmological simulations is presented. The algorithm depends mainly on two parameters, which control the level of…

Astrophysics · Physics 2015-05-13 M. Maciejewski , S. Colombi , V. Springel , C. Alard , F. R. Bouchet

We describe a new method (\textsc{CompaSO}) for identifying groups of particles in cosmological $N$-body simulations. \textsc{CompaSO} builds upon existing spherical overdensity (SO) algorithms by taking into consideration the tidal radius…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-25 Boryana Hadzhiyska , Daniel Eisenstein , Sownak Bose , Lehman H. Garrison , Nina Maksimova

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

This letter presents a CWT-enhanced vibration sensing framework for bearing fault monitoring through spatial localization on time-frequency spectrograms. Vibration signals are transformed into continuous wavelet transform (CWT) spectrograms…

Signal Processing · Electrical Eng. & Systems 2026-04-21 Po-Heng Chou , Wei-Lung Mao , Ru-Ping Lin , Jen-Yu Chiu , Chun-Yu Yeh

The analysis of cosmological galaxy surveys requires realistic simulations for their interpretation. Forward modelling is a powerful method to simulate galaxy clustering without the need for an underlying complex model. This approach…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-07 Pascale Berner , Alexandre Refregier , Raphael Sgier , Tomasz Kacprzak , Luca Tortorelli , Pierluigi Monaco

The Continuous Wavelet Transform (CWT) is an effective tool for feature extraction in acoustic recognition using Convolutional Neural Networks (CNNs), particularly when applied to non-stationary audio. However, its high computational cost…

Audio and Speech Processing · Electrical Eng. & Systems 2025-12-01 Dang Thoai Phan , Tuan Anh Huynh , Van Tuan Pham , Cao Minh Tran , Van Thuan Mai , Ngoc Quy Tran

Cloud detection is a specialized application of image recognition and object detection using remotely sensed data. The task presents a number of challenges, including analyzing images obtained in visible, infrared and multi-spectral…

Signal Processing · Electrical Eng. & Systems 2020-07-28 Philippe Reiter

A recent comparison of the massive galaxy cluster Abell 2744 with the Millennium XXL (MXXL) N-body simulation has hinted at a tension between the observed substructure distribution and the predictions of LambdaCDM. Follow-up investigations…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-26 J. Schwinn , C. M. Baugh , M. Jauzac , M. Bartelmann , D. Eckert

We present VELOCIraptor, a massively parallel galaxy/(sub)halo finder that is also capable of robustly identifying tidally disrupted objects and separate stellar halos from galaxies. The code is written in c++11, use the MPI and OpenMP…

(Abridged) We present a semi-analytic model for Cold Dark Matter halo substructure that can be used as a framework for studying galaxy formation and an ingredient in halo models of galaxy clustering. We perform a comprehensive comparison of…

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

We investigate the structural properties, distribution and abundance of LCDM dark matter subhaloes using the Phi-4096 and Uchuu suite of N-body cosmological simulations. Thanks to the combination of their large volume, high mass resolution…

This work explores the ability of computer vision algorithms to characterise dark matter haloes formed in different models of structure formation. We produce surface mass density maps of the most massive haloes in a suite of eight numerical…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Julian Merten , Quim Llorens , Hans Winther

We present a model to track the orbital evolution of "unresolved subhaloes" (USHs) in cosmological simulations. USHs are subhaloes that are no longer distinguished by halo finders as self-bound overdensities within their larger host system…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-07 Facundo M. Delfino , Claudia G. Scoccola , Sofia A. Cora , Cristian A. Vega-Martinez , Ignacio D. Gargiulo

We present a new algorithm for identifying the substructure within simulated dark matter haloes. The method is an extension of that proposed by Tormen et al. (2004) and Giocoli et al. (2008a), which identifies a subhalo as a group of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Carlo Giocoli , Giuseppe Tormen , Ravi K. Sheth , Frank C. van den Bosch

Using the high-resolution $N$-body cosmological simulation COLOR, we explore the cosmic web (CW) environmental effects on subhalo populations and their internal properties. We use CaCTus, which incorporates an implementation of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-08 Feven Markos Hunde , Oliver Newton , Wojciech A. Hellwing , Maciej Bilicki , Krishna Naidoo

Large-scale sky surveys require companion large volume simulated mock catalogs. To ensure precision cosmology studies are unbiased, the correlations in these mocks between galaxy properties and their large-scale environments must be…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-25 Sujatha Ramakrishnan , Aseem Paranjape , Ravi K. Sheth