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We present the first cluster catalogue extracted from the UKIRT Infrared Deep Sky Survey Early Data Release. The catalogue is created using UKIDSS Ultra Deep Survey infrared J and K data combined with 3.6 micro-m and 4.5 micro-m Spitzer…

We have performed a detailed analysis of the ability of the friends-of-friends algorithm in identifying real galaxy systems in deep surveys such as the future Javalambre Physics of the Accelerating Universe Astrophysical Survey. Our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 A. Zandivarez , E. Díaz-Giménez , C. Mendes de Oliveira , B. Ascaso , N. Benítez , R. Dupke , L. Sodré , . , J. Irwin

We have developed a multiscale structure identification algorithm for the detection of overdensities in galaxy data that identifies structures having radii within a user-defined range. Our "multiscale probability mapping" technique combines…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Anthony G. Smith , Andrew M. Hopkins , Richard W. Hunstead , Kevin A. Pimbblet

We present a comparison between two optical cluster finding methods: a matched filter algorithm using galaxy angular coordinates and magnitudes, and a percolation algorithm using also redshift information. We test the algorithms on two mock…

Astrophysics · Physics 2009-11-10 D. Rizzo , C. Adami , S. Bardelli , A. Cappi , E. Zucca , B. Guiderdoni , G. Chincarini , A. Mazure

We develop the Blooming Tree Algorithm, a new technique that uses spectroscopic redshift data alone to identify the substructures and the surrounding groups of galaxy clusters, along with their member galaxies. Based on the estimated…

Astrophysics of Galaxies · Physics 2018-06-21 Heng Yu , Antonaldo Diaferio , Ana Laura Serra , Marco Baldi

We present a structure finding algorithm designed to identify galaxy groups in photometric redshift data sets: the probability friends-of-friends (pFoF) algorithm. This algorithm is derived by combining the friends-of-friends algorithm in…

Astrophysics · Physics 2009-11-13 I-hui Li , Howard K. C. Yee

We present an automated method to detect populations of groups in galaxy redshift catalogs. This method uses both analysis of the redshift distribution along lines of sight in fixed cells to detect elementary structures and a…

Astrophysics · Physics 2009-11-07 C. Adami , A. Mazure

In data stream clustering, systematic theory of stream clustering algorithms remains relatively scarce. Recently, density-based methods have gained attention. However, existing algorithms struggle to simultaneously handle arbitrarily…

Machine Learning · Computer Science 2026-05-07 Qifen Zeng , Haomin Bao , Yuanzhuo Hu , Zirui Zhang , Yuheng Zheng , Luosheng Wen

Currently, density-based clustering algorithms are widely applied because they can detect clusters with arbitrary shapes. However, they perform poorly in measuring global density, determining reasonable cluster centers or structures,…

Machine Learning · Computer Science 2023-11-02 Mingjie Cai , Zhishan Wu , Qingguo Li , Feng Xu , Jie Zhou

This short document illustrates QLUSTER: a toy model for populations of binary black holes in dense astrophysical environments. QLUSTER is a simple tool to investigate the occurrence and properties of hierarchical black-hole mergers…

High Energy Astrophysical Phenomena · Physics 2023-11-30 Davide Gerosa , Matthew Mould

We address the problem of un-supervised soft-clustering called micro-clustering. The aim of the problem is to enumerate all groups composed of records strongly related to each other, while standard clustering methods separate records at…

Data Structures and Algorithms · Computer Science 2016-06-07 Takeaki Uno , Hiroki Maegawa , Takanobu Nakahara , Yukinobu Hamuro , Ryo Yoshinaka , Makoto Tatsuta

Graph clustering, or community detection, is the task of identifying groups of closely related objects in a large network. In this paper we introduce a new community-detection framework called LambdaCC that is based on a specially weighted…

Data Structures and Algorithms · Computer Science 2018-07-17 Nate Veldt , David Gleich , Anthony Wirth

Context. Groups form the most abundant class of galaxy systems. They act as the principal drivers of galaxy evolution and can be used as tracers of the large-scale structure and the underlying cosmology. However, the detection of galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-16 E. Tempel , R. Kipper , A. Tamm , M. Gramann , M. Einasto , T. Sepp , T. Tuvikene

We have developed a galaxy cluster finding technique based on the Delaunay Tessellation Field Estimator (DTFE) combined with caustic analysis. Our method allows us to recover clusters of galaxies within the mass range of 10^12 to 10^16…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-06 Hector J. Ibarra-Medel , Maritza Lara-Lopez , Omar Lopez-Cruz

We use a large K-selected sample of 299,961 galaxies from the REFINE survey, consisting of a combination of data from three of the deepest near-infrared surveys: UKIDSS UDS, COSMOS/UltraVISTA and CFHTLS-D1/VIDEO, that were homogeneously…

Astrophysics of Galaxies · Physics 2021-07-14 Florian Sarron , Christopher J Conselice

We present a novel approach to identify galaxy clusters that are undergoing a merger using a deep learning approach. This paper uses massive galaxy clusters spanning $0 \leq z \leq 2$ from \textsc{The Three Hundred} project, a suite of…

We present a new cluster-finding algorithm based on a combination of the Voronoi Tessellation and Friends-Of-Friends methods. The algorithm utilises probability distribution functions derived from a photometric redshift analysis and is…

Astrophysics · Physics 2007-05-23 Lee Clewley , Caroline van Breukelen , David Bonfield

The Northern Sky Optical Cluster Survey is a project to create an objective catalog of galaxy clusters over the entire high-galactic-latitude Northern sky, with well understood selection criteria. We use the object catalogs generated from…

Astrophysics · Physics 2016-08-30 R. R. Gal , R. R. DeCarvalho , S. C. Odewahn , S. G. Djorgovski , V. E. Margoniner

Subspace clustering refers to the problem of clustering high-dimensional data points into a union of low-dimensional linear subspaces, where the number of subspaces, their dimensions and orientations are all unknown. In this paper, we…

Machine Learning · Statistics 2014-03-17 Reinhard Heckel , Eirikur Agustsson , Helmut Bölcskei

We apply a halo-based group finder to four large redshift surveys, the 2MRS, 6dFGS, SDSS and 2dFGRS, to construct group catalogs in the low-redshift Universe. The group finder is based on that of Yang et al. but with an improved halo mass…

Astrophysics of Galaxies · Physics 2017-11-02 Seunghwan Lim , Houjun Mo , Yi Lu , Huiyuan Wang , Xiaohu Yang