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The classification of galaxies as spirals or ellipticals is a crucial task in understanding their formation and evolution. With the arrival of large-scale astronomical surveys, such as the Sloan Digital Sky Survey (SDSS), astronomers now…

Computer Vision and Pattern Recognition · Computer Science 2023-12-04 Anusha Guruprasad

The immense amount of time series data produced by astronomical surveys has called for the use of machine learning algorithms to discover and classify several million celestial sources. In the case of variable stars, supervised learning…

Solar and Stellar Astrophysics · Physics 2022-10-12 R. Pantoja , M. Catelan , K. Pichara , P. Protopapas

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…

One of the most important properties of a galaxy is the total stellar mass, or equivalently the stellar mass-to-light ratio (M/L). It is not directly observable, but can be estimated from stellar population synthesis. Currently, a galaxy's…

Astrophysics of Galaxies · Physics 2019-04-24 Wouter Dobbels , Serge Krier , Stephan Pirson , Sébastien Viaene , Gert De Geyter , Samir Salim , Maarten Baes

We examine a general framework for visualizing datasets of high (> 2) dimensionality, and demonstrate it using the morphology of galaxies at moderate redshifts. The distributions of various populations of such galaxies are examined in a…

Astrophysics · Physics 2007-05-23 A. Naim , K. U. Ratnatunga , R. E. Griffiths

Unsupervised machine learning, and in particular data clustering, is a powerful approach for the analysis of datasets and identification of characteristic features occurring throughout a dataset. It is gaining popularity across scientific…

Mesoscale and Nanoscale Physics · Physics 2021-03-23 Maria El Abbassi , Jan Overbeck , Oliver Braun , Michel Calame , Herre S. J. van der Zant , Mickael L. Perrin

We present a new non-parametric method to quantify morphologies of galaxies based on a particular family of learning machines called support vector machines. The method, that can be seen as a generalization of the classical CAS…

Astrophysics · Physics 2009-11-13 M. Huertas-Company , D. Rouan , L. Tasca , G. Soucail , O. Le Fevre

Measuring the morphological parameters of galaxies is a key requirement for studying their formation and evolution. Surveys such as the Sloan Digital Sky Survey (SDSS) have resulted in the availability of very large collections of images,…

Instrumentation and Methods for Astrophysics · Physics 2015-03-25 Sander Dieleman , Kyle W. Willett , Joni Dambre

We train three convolutional neural networks (CNNs) to classify galaxies with Galaxy Zoo 2 dataset and extract the activations from the last fully connected layer or the last average pooling layer of CNNs to study the high-dimensional…

Astrophysics of Galaxies · Physics 2018-07-17 Jia-Ming Dai , Jizhou Tong

[Abridged] We consider how galaxy clustering data, from Mpc to Gpc scales, from upcoming large scale structure surveys, such as Euclid and DESI, can provide discriminating information about the bispectrum shape arising from a variety of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Joyce Byun , Rachel Bean

Mergers are an important aspect of galaxy formation and evolution. We aim to test whether deep learning techniques can be used to reproduce visual classification of observations, physical classification of simulations and highlight any…

Astrophysics of Galaxies · Physics 2019-06-12 W. J. Pearson , L. Wang , J. W. Trayford , C. E. Petrillo , F. F. S. van der Tak

The results of morphological galaxy classifications performed by humans and by automated methods are compared. In particular, a comparison is made between the eyeball classifications of 454 galaxies in the Sloan Digital Sky Survey (SDSS)…

Astrophysics · Physics 2007-05-23 Nicholas M. Ball

Classification will be an important first step for upcoming surveys that will detect billions of new sources such as LSST and Euclid, as well as DESI, 4MOST and MOONS. The application of traditional methods of model fitting and…

Astrophysics of Galaxies · Physics 2020-01-29 Crispin Logan , Sotiria Fotopoulou

Wide-field, multi-band surveys now detect millions of unresolved sources in nearby galaxy clusters, yet separating globular clusters (GCs) from foreground stars and background galaxies remains challenging. Scalable, automated classification…

We introduce Deep-CEE (Deep Learning for Galaxy Cluster Extraction and Evaluation), a proof of concept for a novel deep learning technique, applied directly to wide-field colour imaging to search for galaxy clusters, without the need for…

Astrophysics of Galaxies · Physics 2019-11-26 Matthew C. Chan , John P. Stott

The morphological properties of galaxies between $21 {\rm~mag} < I < 25 {\rm~mag}$ in the {\em Hubble Deep Field} are investigated using a quantitative classification system based on measurements of the central concentration and asymmetry…

We present a morphological catalogue for $\sim$ 670,000 galaxies in the Sloan Digital Sky Survey in two flavours: T-Type, related to the Hubble sequence, and Galaxy Zoo 2 (GZ2 hereafter) classification scheme. By combining accurate existing…

Astrophysics of Galaxies · Physics 2018-02-28 H. Domínguez Sánchez , M. Huertas-Company , M. Bernardi , D. Tuccillo , J. L. Fischer

Classifying the morphologies of galaxies is an important step in understanding their physical properties and evolutionary histories. The advent of large-scale surveys has hastened the need to develop techniques for automated morphological…

Astrophysics of Galaxies · Physics 2021-12-28 Mitchell K. Cavanagh , Kenji Bekki , Brent A. Groves

With the development of a series of Galaxy sky surveys in recent years, the observations increased rapidly, which makes the research of machine learning methods for galaxy image recognition a hot topic. Available automatic galaxy image…

Instrumentation and Methods for Astrophysics · Physics 2023-12-27 Xiaohua Ma , Xiangru Li , Ali Luo , Jinqu Zhang , Hui Li

We use automated surface photometry and pattern classification techniques to morphologically classify galaxies. The two-dimensional light distribution of a galaxy is reconstructed using Fourier series fits to azimuthal profiles computed in…

Astrophysics · Physics 2009-11-07 S. C. Odewahn , S. H. Cohen , R. A. Windhorst , N. S. Philip