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Measuring the evolution in the clustering of galaxies over a large redshift range is a challenging problem. For a two-dimensional galaxy catalog, however, we can measure the galaxy-galaxy angular correlation function which provides…

Astrophysics · Physics 2009-10-31 Robert J. Brunner , Andrew J. Connolly , Alex S. Szalay

Standard maximum-likelihood estimators for binary-star and exoplanet eccentricities are biased high, in the sense that the estimated eccentricity tends to be larger than the true eccentricity. As with most non-trivial observables, a simple…

Solar and Stellar Astrophysics · Physics 2011-01-19 David W. Hogg , Adam D. Myers , Jo Bovy

Observations of star formation rates (SFRs) in galaxies provide vital clues to the physical nature of the Hubble sequence, and are key probes of the evolutionary properties of galaxies. The focus of this review is on the broad patterns in…

Astrophysics · Physics 2012-08-27 Robert C. Kennicutt,

In the last years, Astroinformatics has become a well defined paradigm for many fields of Astronomy. In this work we demonstrate the potential of a multidisciplinary approach to identify globular clusters (GCs) in the Fornax cluster of…

We are carrying out a programme to measure the evolution of the stellar and dynamical masses and M/L ratios for a sizeable sample of morphologically-classified disk galaxies in rich galaxy clusters at 0.2<z<0.9. Using FORS2 at the VLT we…

Astrophysics · Physics 2009-11-07 A. Aragon-Salamanca , B. Milvang-Jensen , G. Hau , I. Jorgensen , J. Hjorth

Cosmographic approach, a Taylor expansion of the Hubble function, has been used as a model-independent method to investigate the evolution of the universe in the presence of cosmological data. Apart from possible technical problems like the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-04 Ahmad Mehrabi , Mehdi Rezaei

The formation and evolution of disk galaxies in the cosmological context is studied. We consider the observable properties of disk galaxies and treat the disk formation and galactic evolutionary processes in a self-consistent fashion. We…

Astrophysics · Physics 2007-05-23 Claudio Firmani , Vladimir Avila-Reese , Xavier Hernández

It appears that the dynamical status of clusters and groups of galaxies is related to the large-scale structure of the Universe. A few interesting trends have been established: (1) The Cluster Substructure - Alignment Connection, by which…

Astrophysics · Physics 2009-11-10 Manolis Plionis

The field of astronomy is experiencing a data explosion driven by significant advances in observational instrumentation, and classical methods often fall short of addressing the complexity of modern astronomical datasets. Probabilistic…

Instrumentation and Methods for Astrophysics · Physics 2026-01-26 Abigail Sheerin , Giuseppe Vinci

Deep clustering outperforms conventional clustering by mutually promoting representation learning and cluster assignment. However, most existing deep clustering methods suffer from two major drawbacks. First, most cluster assignment methods…

Computer Vision and Pattern Recognition · Computer Science 2022-02-23 Hanxuan Wang , Na Lu , Qinyang Liu

Galaxies can be described by features of their optical spectra such as oxygen emission lines, or morphological features such as spiral arms. Although spectroscopy provides a rich description of the physical processes that govern galaxy…

Instrumentation and Methods for Astrophysics · Physics 2020-12-01 John F. Wu , J. E. G. Peek

A major goal of contemporary astrophysics is understanding the origin of the most massive galaxies in the universe, particularly nearby ellipticals and spirals. Theoretical models of galaxy formation have existed for many decades, although…

Astrophysics · Physics 2016-08-30 Christopher J. Conselice

Recent advancements in areas such as natural language processing and computer vision rely on intricate and massive models that have been trained using vast amounts of unlabelled or partly labeled data and training or deploying these…

Computer Vision and Pattern Recognition · Computer Science 2023-04-28 Rishit Dagli

Star-galaxy classification is one of the most fundamental data-processing tasks in survey astronomy, and a critical starting point for the scientific exploitation of survey data. For bright sources this classification can be done with…

Instrumentation and Methods for Astrophysics · Physics 2013-07-30 Marc Henrion , Daniel J. Mortlock , David J. Hand , Axel Gandy

Convex clustering is a recent stable alternative to hierarchical clustering. It formulates the recovery of progressively coalescing clusters as a regularized convex problem. While convex clustering was originally designed for handling…

Applications · Statistics 2019-12-12 Claire Donnat , Susan Holmes

Modern galaxy cluster science is a multi-wavelength endeavor with cornerstones provided by X-ray, optical/IR, mm, and radio measurements. In combination, these observations enable the construction of large, clean, complete cluster catalogs,…

We discuss the application of a class of machine learning algorithms known as decision trees to the process of galactic classification. In particular, we explore the application of oblique decision trees induced with different impurity…

Astrophysics · Physics 2015-06-24 E. Owens , R. E. Griffiths , K. U. Ratnatunga

A detailed analysis of the galaxy distribution in the Southern Sky Redshift Survey (SSRS) by means of the multifractal or scaling formalism is presented. It is shown that galaxies cluster in different ways according to their morphological…

Astrophysics · Physics 2009-10-22 A. Campos , R. Dominguez-Tenreiro , G. Yepes

Clusters of galaxies are the largest gravitationally-bound objects in the Universe, having diameters on order of Mpc. Our work asked whether their shapes (morphologies) change over time as the Universe ages. We observed a sample of 165…

Astrophysics · Physics 2008-10-23 Brian C. Hart

In hierarchical cosmologies the evolution of galaxy clustering depends both on cosmological quantities such as Omega and Lambda, which determine how dark matter halos form and evolve, and on the physical processes - cooling, star formation…