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Related papers: Observing Merger Trees in a New Light

200 papers

We describe a new methodology to analyze the reionization process in numerical simulations: the chronology and the geometry of reionization is investigated by means of merger histories of individual HII regions. From the merger tree of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Jonathan Chardin , Dominique Aubert , Pierre Ocvirk

We construct merger trees from the largest database of dark matter haloes to date provided by the Millennium simulation to quantify the merger rates of haloes over a broad range of descendant halo mass (1e12 < M0 < 1e15 Msun), progenitor…

Astrophysics · Physics 2009-11-13 Onsi Fakhouri , Chung-Pei Ma

We describe a new visualization tool, dubbed HCMapper, that visually helps to compare a pair of dendrograms computed on the same dataset by displaying multiscale partition-based layered structures. The dendrograms are obtained by…

Human-Computer Interaction · Computer Science 2016-02-23 Gautier Marti , Philippe Donnat , Frank Nielsen , Philippe Very

We propose methods for the analysis of hierarchical clustering that fully use the multi-resolution structure provided by a dendrogram. Specifically, we propose a loss for choosing between clustering methods, a feature importance score and a…

Methodology · Statistics 2023-01-31 Luben M. C. Cabezas , Rafael Izbicki , Rafael B. Stern

Dark matter subhalos are the remnants of (incomplete) halo mergers. Identifying them and establishing their evolutionary links in the form of merger trees is one of the most important applications of cosmological simulations. The…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-13 Jiaxin Han , Shaun Cole , Carlos S. Frenk , Alejandro Benitez-Llambay , John Helly

"mdendro" is an R package that provides a comprehensive collection of linkage methods for agglomerative hierarchical clustering on a matrix of proximity data (distances or similarities), returning a multifurcated dendrogram or…

Information Retrieval · Computer Science 2025-09-16 Alberto Fernández , Sergio Gómez

A common approach in semi-analytic modeling of galaxy formation is to construct Monte Carlo realizations of merger histories of dark matter halos whose masses are sampled from a halo mass function. Both the mass function itself, and the…

Astrophysics of Galaxies · Physics 2017-03-22 Andrew J. Benson

We have developed a new semi-analytic model for the formation and evolution of structure on galaxy, group and cluster scales. The model combines merger trees with a detailed, spatially resolved description of the dynamical evolution of halo…

Astrophysics · Physics 2007-05-23 James E. Taylor , Arif Babul

We use N-body cosmological simulations and empirical galaxy models to study the merger history of dwarf-mass galaxies (with M_halo~10^10 M_Sun). Our input galaxy models describe the stellar mass-halo mass relation, and the galaxy occupation…

Astrophysics of Galaxies · Physics 2022-01-04 Alis J. Deason , Sownak Bose , Azadeh Fattahi , Nicola C. Amorisco , Wojciech Hellwing , Carlos S. Frenk

We describe a semi-analytic model to predict the triaxial shapes of dark matter halos utilizing the sequences of random merging events captured in merger trees to follow the evolution of each halo's energy tensor. When coupled with a simple…

Astrophysics of Galaxies · Physics 2026-03-18 Paul Menker , Andrew J. Benson

Complex systems are usually represented as an intricate set of relations between their components forming a complex graph or network. The understanding of their functioning and emergent properties are strongly related to their structural…

Data Analysis, Statistics and Probability · Physics 2014-01-08 Sergio Gomez , Alberto Fernandez , Clara Granell , Alex Arenas

We study the growth of dark matter halos in the concordance LCDM cosmology using several N-body simulations of large cosmological volumes. We build merger trees from the Millennium and Millennium-II simulations, covering a range 10^9-10^15…

Cosmology and Nongalactic Astrophysics · Physics 2010-07-21 Shy Genel , Nicolas Bouché , Thorsten Naab , Amiel Sternberg , Reinhard Genzel

We present a new exploratory framework to model galaxy formation and evolution in a hierarchical universe by using machine learning (ML). Our motivations are two-fold: (1) presenting a new, promising technique to study galaxy formation, and…

Astrophysics of Galaxies · Physics 2015-11-30 Harshil M. Kamdar , Matthew J. Turk , Robert J. Brunner

The effects of spatial correlations of density fluctuations on merger histories of dark matter haloes (so-called `{\it merger trees}') are analysed. We compare the mass functions of dark haloes derived by a new method for calculating merger…

Astrophysics · Physics 2015-06-24 Masahiro Nagashima , Naoteru Gouda

We present a new algorithm which groups the subhaloes found in cosmological N- body simulations by structure finders such as SUBFIND into dark matter haloes whose formation histories are strictly hierarchical. One advantage of these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Lilian Jiang , John C. Helly , Shaun Cole , Carlos S. Frenk

The information extracted from large galaxy surveys with the likes of DES, DESI, Euclid, LSST, SKA, and WFIRST will be greatly enhanced if the resultant galaxy catalogues can be cross-correlated with one another. Predicting the nature of…

Astrophysics of Galaxies · Physics 2017-08-15 Philip Bull

Understanding how galaxy populations emerge and evolve from the growth of dark matter structure is a central challenge in galaxy formation theory. Semi-analytic models (SAMs) provide an efficient framework to address this problem, but…

Astrophysics of Galaxies · Physics 2026-05-05 Xuejie Li , Zhongxu Zhai , Xiaohu Yang , Andrew Benson , Yun Wang

We investigate a series of galaxy properties computed using the merger trees and environmental histories from dark matter only cosmological simulations, using a semi-recurrent neural network producing self-consistent predictions of galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Harry George Chittenden , Jayashree Behera , Rita Tojeiro

Structure identification in cosmological simulations plays an important role in analysing simulation outputs. The definition of these structures directly impacts the inferred properties derived from these simulations. This paper proposes a…

Astrophysics of Galaxies · Physics 2025-01-16 Robel Geda , Romain Teyssier

We propose a common terminology for use in describing both temporal merger trees and spatial structure trees for dark-matter halos. We specify a unified data format in HDF5 and provide example I/O routines in C, FORTRAN and PYTHON.