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Testing theories of hierarchical structure formation requires estimating the distribution of galaxy morphologies and its change with redshift. One aspect of this investigation involves identifying galaxies with disturbed morphologies (e.g.,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 P. E. Freeman , R. Izbicki , A. B. Lee , J. A. Newman , C. J. Conselice , A. M. Koekemoer , J. M. Lotz , M. Mozena

We have carried out a deep infrared imaging survey (1.1um and 1.6um) of the Hubble Deep Field North (HDF-N) using NICMOS on board the Hubble Space Telescope. The combined WFPC2+NICMOS data set lets us study galaxy morphologies, colors and…

Astrophysics · Physics 2007-05-23 Mark Dickinson

The upcoming galaxy large-scale surveys, such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), will generate photometry for billions of galaxies. The interpretation of large-scale weak lensing maps, as well as the…

Instrumentation and Methods for Astrophysics · Physics 2025-10-01 Alvaro Callejas-Tavera , Erik Molino-Minero-Re , Octavio Valenzuela

We apply four statistical learning methods to a sample of $7941$ galaxies ($z<0.06$) from the Galaxy and Mass Assembly (GAMA) survey to test the feasibility of using automated algorithms to classify galaxies. Using $10$ features measured…

Methods. We used different galaxy classification techniques: human labeling, multi-photometry diagrams, Naive Bayes, Logistic Regression, Support Vector Machine, Random Forest, k-Nearest Neighbors, and k-fold validation. Results. We present…

Astrophysics of Galaxies · Physics 2021-06-09 I. B. Vavilova , D. V. Dobrycheva , M. Yu. Vasylenko , A. A. Elyiv , O. V. Melnyk , V. Khramtsov

The major uncertainties in studies of the multi-scale structure of the Universe arise not from observational errors but from the variety of legitimate definitions and detection methods for individual structures. To facilitate the study of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 M. J. Way , P. R. Gazis , Jeffrey D. Scargle

Bars are important drivers of galaxy evolution, influencing many physical processes and properties. Characterising bars is a difficult task, especially in large-scale surveys. In this work, we propose a novel morphological segmentation…

Astrophysics of Galaxies · Physics 2024-05-22 Mitchell K. Cavanagh , Kenji Bekki , Brent A. Groves

Galaxy morphology encodes key information about formation and evolution. Large imaging surveys require automated, reproducible methods beyond visual inspection. Non--parametric indices provide an useful framework, but their performance must…

Modeling the mass distribution of galaxy-scale strong gravitational lenses is a task of increasing difficulty. The high-resolution and depth of imaging data now available render simple analytical forms ineffective at capturing lens…

Instrumentation and Methods for Astrophysics · Physics 2022-12-21 Aymeric Galan , Georgios Vernardos , Austin Peel , Frédéric Courbin , Jean-Luc Starck

Variations in the photometric parameters of stellar systems as a function of their evolution and the stellar populations comprising them are investigated. A set of seven evolutionary models with an exponential decrease in the star-formation…

Galaxy morphology classification plays a crucial role in understanding the structure and evolution of the universe. With galaxy observation data growing exponentially, machine learning has become a core technology for this classification…

Astrophysics of Galaxies · Physics 2025-05-29 Zhijian Luo , Jianzhen Chen , Zhu Chen , Shaohua Zhang , Liping Fu , Hubing Xiao , Chenggang Shu

Self-organizing maps (SOMs) are a technique that has been used with high-dimensional data vectors to develop an archetypal set of states (nodes) that span, in some sense, the high-dimensional space. Noteworthy applications include weather…

Applications · Statistics 2009-01-23 Huiyan Sang , Alan E. Gelfand , Chris Lennard , Gabriele Hegerl , Bruce Hewitson

We present an analysis of the growth of stellar mass with cosmic time partitioned according to galaxy morphology. Using a well-defined catalog of 2150 galaxies based, in part, on archival data in the GOODS fields, we assign morphological…

Astrophysics · Physics 2009-11-10 K. Bundy , R. S. Ellis , C. J. Conselice

Phylogenetic approaches are finding more and more applications outside the field of biology. Astrophysics is no exception since an overwhelming amount of multivariate data has appeared in the last twenty years or so. In particular, the…

Instrumentation and Methods for Astrophysics · Physics 2016-06-02 Didier Fraix-Burnet

From mock Hubble Space Telescope images, we quantify non-parametric statistics of galaxy morphology, thereby predicting the emergence of relationships among stellar mass, star formation, and observed rest-frame optical structure at 1 < z <…

Thanks to decades of observations using the Hubble Space Telescope (HST), the structure of galaxies at redshift $z>2$ has been widely studied in the rest-frame ultraviolet regime, which traces recent star formation from young stellar…

We introduce a new 2-D hexagon technique to probe the topological structure of the universe, in which we map regions of the sky with high and low galaxy densities onto a 2-D lattice of hexagon unit cells, We define filled cells as…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Yongfeng Wu , Weike Xiao

We analyze the optical morphologies of galaxies in the IllustrisTNG simulation at $z\sim0$ with a Convolutional Neural Network trained on visual morphologies in the Sloan Digital Sky Survey. We generate mock SDSS images of a mass complete…

For the joint analysis of second-order weak lensing and galaxy clustering statistics, so-called $3{\times}2$ analyses, the selection and characterization of optimal galaxy samples is a major area of research. One promising choice is to use…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-10 Andrés N. Salcedo , Tim Eifler , Peter Behroozi

(Abridged) We determine the quantitative morphology and star formation properties of galaxies in six nearby X-ray detected, poor groups using multi-object spectroscopy and wide-field R imaging. We measure structural parameters for each…

Astrophysics · Physics 2009-10-31 Kim-Vy H. Tran , Luc Simard , Ann I. Zabludoff , John S. Mulchaey