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Three methods for detecting and characterizing structure in point data, such as that generated by redshift surveys, are described: classification using self-organizing maps, segmentation using Bayesian blocks, and density estimation using…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 M. J. Way , P. R. Gazis , Jeffrey D. Scargle

The decision boundaries of Bayes classifier are optimal because they lead to maximum probability of correct decision. It means if we knew the prior probabilities and the class-conditional densities, we could design a classifier which gives…

Computer Vision and Pattern Recognition · Computer Science 2012-07-23 Mahmoud Khademi , Mohammad T. Manzuri-Shalmani , Meharn safayani

The generalized density is a product of a density function and a weight function. For example, the average local brightness of an astronomical image is the probability of finding a galaxy times the mean brightness of the galaxy. We propose…

Methodology · Statistics 2014-06-10 Yen-Chi Chen , Christopher R. Genovese , Larry Wasserman

The HST data archive contains images of several nearby spirals, suitable for detailed studies of the properties of individual star clusters and their surroundings. By combining structural information derived from HST images with…

Astrophysics · Physics 2007-05-23 Soeren S. Larsen

We calculate the observable signatures of the first generation of stars at high redshift (5<z<100). To determine the cosmic star-formation history, we use an extension of the Press-Schechter formalism for Cold Dark Matter (CDM) cosmologies…

Astrophysics · Physics 2007-05-23 Zoltan Haiman , Abraham Loeb

Lens magnification by galaxy clusters induces characteristic spatial variations in the number counts of background sources, amplifying their observed fluxes and expanding the area of sky, the net effect of which, known as magnification…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Keiichi Umetsu

We consider the task of detecting a salient cluster in a sensor network, that is, an undirected graph with a random variable attached to each node. Motivated by recent research in environmental statistics and the drive to compete with the…

Statistics Theory · Mathematics 2013-03-22 Ery Arias-Castro , Geoffrey R. Grimmett

We report the discovery of a cluster of galaxies via its weak gravitational lensing effect on background galaxies, the first spectroscopically confirmed cluster to be discovered through its gravitational effects rather than by its…

Astrophysics · Physics 2009-11-06 D. Wittman , J. A. Tyson , V. E. Margoniner , J. G. Cohen , I. P. Dell'Antonio

We present a new method for quantifying the abundance of satellites around field galaxies and in groups. The method is designed to work with samples, such as local photometric redshift catalogues, that do not have full spectroscopic…

Astrophysics of Galaxies · Physics 2021-12-21 Chengyu Xi , James E. Taylor

The effects of many physical processes in the intracluster medium of galaxy clusters imprint themselves in X-ray surface brightness images. It is therefore important to choose optimal methods for extracting information from and enhancing…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-15 J. S. Sanders , A. C. Fabian , H. R. Russell , S. A. Walker , K. M. Blundell

The determination of the mean density of the Universe is a long standing problem of modern cosmology. The number density evolution of x-ray clusters at a fixed temperature is a powerful cosmological test, new in nature (Oukbir and…

Astrophysics · Physics 2009-10-30 Alain Blanchard , James G. Bartlett , Rachida Sadat

Current learning-based methods predict NeRF or 3D Gaussians from point clouds to achieve photo-realistic rendering but still depend on categorical priors, dense point clouds, or additional refinements. Hence, we introduce a novel point…

Computer Vision and Pattern Recognition · Computer Science 2025-05-15 Ma Changfeng , Bi Ran , Guo Jie , Wang Chongjun , Guo Yanwen

Understanding the star-formation properties of galaxies as a function of cosmic epoch is a critical exercise in studies of galaxy evolution. Traditionally, stellar population synthesis models have been used to obtain best fit parameters…

Astrophysics of Galaxies · Physics 2020-03-04 Shraddha Surana , Yogesh Wadadekar , Omkar Bait , Hrushikesh Bhosle

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

We use rest-frame Stromgren photometry to observe clusters of galaxies in a self-consistent manner from z=0 to z=0.8. Stromgren photometry of galaxies is an efficient compromise between standard broad-band photometry and spectroscopy, in…

Astrophysics · Physics 2009-10-31 Susanna Steindling , Noah Brosch , Karl Rakos

Most star complexes are in fact complexes of stars, clusters and gas clouds; term "star complexes" was introduced as general one disregarding the preferential content of a complex. Generally the high rate of star formation in a complex is…

Astrophysics · Physics 2010-11-23 Yuri N. Efremov

The R package pdfCluster performs cluster analysis based on a nonparametric estimate of the density of the observed variables. After summarizing the main aspects of the methodology, we describe the features and the usage of the package, and…

Computation · Statistics 2013-01-29 Adelchi Azzalini , Giovanna Menardi

We present new HST I-band images of a sample of 77 nearby, late-type spiral galaxies with low inclination. The main purpose of this catalog is to study the frequency and properties of nuclear star clusters. In 59 galaxies of our sample, we…

Recognition of electron peaks and primary ionization clusters in real data-driven waveform signals is the main goal of research for the usage of the cluster counting technique in particle identification at future colliders. The…

In the outskirts of galaxy clusters, entropy profiles measured from X-ray observations of the hot intracluster medium (ICM) drops off unexpectedly. One possible explanation for this effect is gas clumping, where pockets of cooler and denser…

Instrumentation and Methods for Astrophysics · Physics 2023-10-06 Christian T. Norseth , Daniel R. Wik , John A. ZuHone , Eric D. Miller , Marshall W. Bautz , Michael McDonald