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Galaxy morphology is a fundamental quantity, that is essential not only for the full spectrum of galaxy-evolution studies, but also for a plethora of science in observational cosmology. While a rich literature exists on…

Astrophysics of Galaxies · Physics 2020-01-08 Garreth Martin , Sugata Kaviraj , Alex Hocking , Shaun C. Read , James E. Geach

Significant galaxy mergers throughout cosmic time play a fundamental role in theories of galaxy evolution. The widespread usage of human classifiers to visually assess whether galaxies are in merging systems remains a fundamental component…

Quantifying galaxy morphology is a challenging yet scientifically rewarding task. As the scale of data continues to increase with upcoming surveys, traditional classification methods will struggle to handle the load. We present a solution…

Strong gravitational lenses are a rare and instructive type of astronomical object. Identification has long relied on serendipity, but different strategies -- such as mixed spectroscopy of multiple galaxies along the line of sight, machine…

Star formation rates (SFRs) are a crucial observational tracer of galaxy formation and evolution. Spectroscopy, which is expensive, is traditionally used to estimate SFRs. This study tests the possibility of inferring SFRs of large samples…

Astrophysics of Galaxies · Physics 2024-10-10 Satvik Raghav , Prasanth Ayitapu , Sathwik Narkedimilli , Sujith Makam , Aswath Babu H

Two algorithms for the identification of galaxy groups from redshift surveys are tested by application to simulated data derived from N-body simulation. The accuracy of the membership assignments by these algorithms is studied in a…

Astrophysics · Physics 2009-10-22 James J. Frederic

Classifying galaxies is an essential step for studying their structures and dynamics. Using GalaxyZoo2 (GZ2) fractions thresholds, we collect 545 and 11,735 samples in non-galaxy and galaxy classes, respectively. We compute the Zernike…

Instrumentation and Methods for Astrophysics · Physics 2025-01-20 Hamed Ghaderi , Nasibe Alipour , Hossein Safari

We use data from the Galaxy And Mass Assembly (GAMA) survey in the redshift range 0.01$<$z$<$0.1 (8399 galaxies in $g$ to $K_s$ bands) to derive the stellar mass $-$ half-light radius relations for various divisions of 'early' and…

Aims. We explore machine learning techniques to forecast star formation rate, stellar mass, and metallicity across galaxies with redshifts ranging from 0.01 to 0.3. Methods. Leveraging CatBoost and deep learning architectures, we utilize…

Astrophysics of Galaxies · Physics 2024-05-27 F. Z. Zeraatgari , F. Hafezianzadeh , Y. -X. Zhang , A. Mosallanezhad , J. -Y. Zhang

We present a study on galaxy detection and shape classification using topometric clustering algorithms. We first use the DBSCAN algorithm to extract, from CCD frames, groups of adjacent pixels with significant fluxes and we then apply the…

Instrumentation and Methods for Astrophysics · Physics 2016-10-12 A. Tramacere , D. Paraficz , P. Dubath , J. -P. Kneib , F. Courbin

In order to obtain morphological information of unlabeled galaxies, we present an unsupervised machine-learning (UML) method for morphological classification of galaxies, which can be summarized as two aspects: (1) the methodology of…

Astrophysics of Galaxies · Physics 2022-02-02 C. C. Zhou , Y. Z. Gu , G. W. Fang , Z. S. Lin

We apply the spectral energy distribution (SED) fitting code ProSpect to multiwavelength imaging for $\sim$7,000 galaxies from the GAMA survey at $z<0.06$, in order to extract their star formation histories. We combine a parametric…

Based on the Sloan Digital Sky Survey Data Release 5 Galaxy Sample, we explore photometric morphology classification and redshift estimation of galaxies using photometric data and known spectroscopic redshifts. An unsupervised method,…

Astrophysics · Physics 2009-11-13 Yanxia Zhang , Lili Li , Yongheng Zhao

In this paper, a deep convolutional neural network architecture for galaxies classification is presented. The galaxy can be classified based on its features into main three categories Elliptical, Spiral, and Irregular. The proposed deep…

Computer Vision and Pattern Recognition · Computer Science 2017-09-08 Nour Eldeen M. Khalifa , Mohamed Hamed N. Taha , Aboul Ella Hassanien , I. M. Selim

We address the problem of morphological classification of galaxies from the Galaxy Zoo DECaLS dataset using classical machine learning techniques. Our approach employs a dimensionality reduction method followed by a classical classifier to…

Astrophysics of Galaxies · Physics 2025-04-23 Vasyl Semenov , Vitalii Tymchyshyn , Volodymyr Bezguba , Maksym Tsizh , Andrii Khlevniuk

In recent decades, large-scale sky surveys such as Sloan Digital Sky Survey (SDSS) have resulted in generation of tremendous amount of data. The classification of this enormous amount of data by astronomers is time consuming. To simplify…

Instrumentation and Methods for Astrophysics · Physics 2022-11-02 Sarvesh Gharat , Yogesh Dandawate

There is an obvious need for automated classification of galaxies, as the number of observed galaxies increases very fast. We examine several approaches to this problem, utilising {\em Artificial Neural Networks} (ANNs). We quote results…

Astrophysics · Physics 2009-10-22 Avi Naim

Merging galaxies play a key role in galaxy evolution, and progress in our understanding of galaxy evolution is slowed by the difficulty of making accurate galaxy merger identifications. We use GADGET-3 hydrodynamical simulations of merging…

Astrophysics of Galaxies · Physics 2020-03-18 Nevin , R. , Blecha , L. , Comerford , J. , Greene , J

We use the Random Forest (RF) algorithm to develop a tool for automated activity classification of galaxies into 5 different classes: Star-forming (SF), AGN, LINER, Composite, and Passive. We train the algorithm on a combination of mid-IR…

Astrophysics of Galaxies · Physics 2023-03-22 Elias Kyritsis , Charalampos Daoutis , Andreas Zezas , Konstantinos Kouroumpatzakis

Galaxy morphology offers significant insights into the evolutionary pathways and underlying physics of galaxies. As astronomical data grows with surveys such as Euclid and Vera C. Rubin , there is a need for tools to classify and analyze…

Instrumentation and Methods for Astrophysics · Physics 2024-01-18 I. Kolesnikov , V. M. Sampaio , R. R. de Carvalho , C. Conselice , S. B. Rembold , C. L. Mendes , R. R. Rosa