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Stars mostly form in groups consisting of a few dozen to several ten thousand members. For 30 years, theoretical models provide a basic concept of how such star clusters form and develop: they originate from the gas and dust of collapsing…

Astrophysics of Galaxies · Physics 2015-06-22 S. Pfalzner , G. Parmentier , M. Steinhausen , K. Vincke , K. Menten

We study structural clustering on graphs in dynamic scenarios, where the graphs can be updated by arbitrary insertions or deletions of edges/vertices. The goal is to efficiently compute structural clustering results for any clustering…

Data Structures and Algorithms · Computer Science 2024-11-22 Zhuowei Zhao , Junhao Gan , Boyu Ruan , Zhifeng Bao , Jianzhong Qi , Sibo Wang

We have developed a method for detecting clusters in large imaging surveys, based on the detection of structures in galaxy density maps made in slices of photometric redshifts. This method was first applied to the Canada France Hawaii…

This paper introduces {\em fusion subspace clustering}, a novel method to learn low-dimensional structures that approximate large scale yet highly incomplete data. The main idea is to assign each datum to a subspace of its own, and minimize…

Machine Learning · Computer Science 2022-05-24 Usman Mahmood , Daniel Pimentel-Alarcón

We propose a method for the unsupervised clustering of hyperspectral images based on spatially regularized spectral clustering with ultrametric path distances. The proposed method efficiently combines data density and geometry to…

Computer Vision and Pattern Recognition · Computer Science 2020-04-13 Shukun Zhang , James M. Murphy

We present a selection of candidates of clusters and protoclusters of galaxies identified in the photometric data of the HSC-SSP Wide Public Data Release 3 (PDR3), spanning the redshift range $\rm 0.1 \leq z \leq 2$. The selection method,…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Marcelo C. Vicentin , Laerte Sodré , Michael A. Strauss , Erik V. R. de Lima , Pablo Araya-Araya

Gravitational lensing by clusters of galaxies offers a powerful probe of their structure and mass distribution. Deriving a lens magnification map for a galaxy cluster is a classic inversion problem and many methods have been developed over…

We have obtained HST-NICMOS observations of five of M31's most metal rich globular clusters. These data allow photometry of individual stars in the clusters and their surrounding fields. However, to achieve our goals -- obtain accurate…

We present a description of the observations and data reduction procedures for an extensive spectroscopic and multi-band photometric study of nine high redshift, optically-selected cluster candidates. The primary goal of the survey is to…

Astrophysics · Physics 2009-10-30 J. B. Oke , Marc Postman , Lori Lubin

Context. Simulating stellar dynamics in a molecular cloud environment is numerically challenging due to the strong coupling between young stars and their surrounding gas, and the large range of length and time scales. Aims. This paper is…

Astrophysics of Galaxies · Physics 2025-10-08 Yann Bernard , Estelle Moraux , Daniel J. Price , Frédérique Motte , Fabien Louvet , Isabelle Joncour

The clustering of galaxy clusters is a powerful cosmological tool, which can help to break degeneracies between parameters when combined with other cosmological observables. We aim to demonstrate its potential in constraining cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-16 Alessandra Fumagalli , Matteo Costanzi , Alexandro Saro , Tiago Castro , Stefano Borgani

Star formation in molecular clouds is clumpy, hierarchically subclustered. Fractal structure also emerges in hydro-dynamical simulations of star-forming clouds. Simulating the formation of realistic star clusters with hydro-dynamical…

Quality assessments of models in unsupervised learning and clustering verification in particular have been a long-standing problem in the machine learning research. The lack of robust and universally applicable cluster validity scores often…

Machine Learning · Statistics 2018-03-30 Luzie Helfmann , Johannes von Lindheim , Mattes Mollenhauer , Ralf Banisch

We present an approach that improves the search for reliable astrophysical parameters (e.g. age, mass, and distance) of differentially-reddened, pre-main sequence-rich star clusters. It involves simulating conditions related to the…

Astrophysics of Galaxies · Physics 2015-06-03 Charles Bonatto , Eduardo Bica , Eliade F. Lima

According to the current cosmological paradigm, large scale structures form hierarchically in the Universe. Clusters of galaxies grow through a continuous accretion of mass. Nevertheless, the rate and manner of mass accretion events are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 J. Alfonso L. Aguerri , Ruben Sanchez-Janssen

In computer vision, the estimation of the fundamental matrix is a basic problem that has been extensively studied. The accuracy of the estimation imposes a significant influence on subsequent tasks such as the camera trajectory…

Computer Vision and Pattern Recognition · Computer Science 2015-04-15 Hao Wu , Yi Wan

Dictionary learning and sparse coding have been widely studied as mechanisms for unsupervised feature learning. Unsupervised learning could bring enormous benefit to the processing of hyperspectral images and to other remote sensing data…

Image and Video Processing · Electrical Eng. & Systems 2022-02-03 Joshua Bruton , Hairong Wang

Observations of galaxy clustering are made in redshift space, which results in distortions to the underlying isotropic distribution of galaxies. These redshift-space distortions (RSD) not only degrade important features of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Yuchan Wang , Baojiu Li , Marius Cautun

While foundation models drive steady progress in image segmentation and diffusion algorithms compose always more realistic images, the seemingly simple problem of identifying recurrent patterns in a collection of images remains very much…

Computer Vision and Pattern Recognition · Computer Science 2026-04-22 Zeynep Sonat Baltacı , Romain Loiseau , Mathieu Aubry

We used the dendrogram algorithm to decompose the surface density distributions of stars into hierarchical structures. These structures were tied to the multiscale structures of star clusters. A similar power-law for the mass-size relation…

Astrophysics of Galaxies · Physics 2024-07-30 J. W. Zhou , Pavel Kroupa , Sami Dib
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