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Understanding the morphology of galaxies is a critical aspect of astrophysics research, providing insight into the formation, evolution, and physical properties of these vast cosmic structures. Various observational and computational…

Astrophysics of Galaxies · Physics 2024-11-27 Ufuk Çakır , Tobias Buck

An empirical method of modeling the stellar spectrum of galaxies is proposed, based on two successive applications of Principal Component Analysis (PCA). PCA is first applied to the newly available stellar library STELIB, supplemented by…

Astrophysics · Physics 2009-11-10 Cheng Li , Ting-Gui Wang , Hong-Yan Zhou , Xiao-Bo Dong , Fu-Zhen Cheng

We present a method to model optical images of galaxies using Expectation Maximization Principal Components Analysis (EMPCA). The method relies on the data alone and does not assume any pre-established model or fitting formula. It preserves…

Astrophysics of Galaxies · Physics 2017-08-16 Matteo Maturi

We have investigated some statistical properties of integrated spectra of galaxies from Kennicutt (1992a) spectrophotometric atlas. The input for the analysis are galaxy spectra sampled in 1300 bins between 3750 \AA~ and 6500 \AA. We make…

Astrophysics · Physics 2015-06-24 Laerte Sodre , Hector Cuevas

We have developed a web tool to perform Principal Component Analysis (PCA, Murtagh & Heck 1987; Kendall 1980) onto spectral data. The method is especially designed to perform spectral classification of galaxies from a sample of input…

Astrophysics of Galaxies · Physics 2009-09-22 Mauricio Ortiz , Gaspar Galaz

We present an algorithm using Principal Component Analysis (PCA) to subtract galaxies from imaging data, and also two algorithms to find strong, galaxy-scale gravitational lenses in the resulting residual image. The combined method is…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 R. Joseph , F. Courbin , R. B. Metcalf , C. Giocoli , P. Hartley , N. Jackson , F. Bellagamba , J. -P. Kneib , L. Koopmans , G. Lemson , M. Meneghetti , G. Meylan , M. Petkova , S. Pires

Here, we present a machine vision approach, combining a VAE framework with PCA, to decipher galaxy images. Using mock gri-band images from the EAGLE simulation, the VAE finds that around 35 features are needed to describe the images. Adding…

Astrophysics of Galaxies · Physics 2025-11-27 Samuel Howie , Ting-Yun Cheng , Carlton M. Baugh

Astronomy has evolved almost exclusively by the use of spectroscopic and imaging techniques, operated separately. With the development of modern technologies it is possible to obtain datacubes in which one combines both techniques…

Instrumentation and Methods for Astrophysics · Physics 2009-11-13 J. E. Steiner , R. B. Menezes , T. V. Ricci , A. S. Oliveira

We apply and compare various Artificial Neural Network (ANN) and other algorithms for automatic morphological classification of galaxies. The ANNs are presented here mathematically, as non-linear extensions of conventional statistical…

Astrophysics · Physics 2015-06-24 O. Lahav , A. Naim , L. Sodre , M. C. Storrie-Lombardi

Principal Component Analysis (PCA) is a well-known multivariate technique used to decorrelate a set of vectors. PCA has been extensively applied in the past to the classification of stellar and galaxy spectra. Here we apply PCA to the…

Astrophysics · Physics 2007-05-23 I. Ferreras , B. Rogers , O. Lahav , .

Important but rare and subtle processes driving galaxy morphology and star-formation may be missed by traditional spiral, elliptical, irregular or S\'ersic bulge/disk classifications. To overcome this limitation, we use a principal…

We describe application of the `shapelet' linear decomposition of galaxy images to morphological classification using images of $\sim$ 3000 galaxies from the Sloan Digital Sky Survey. After decomposing the galaxies we perform a principal…

Astrophysics · Physics 2009-11-10 Brandon C. Kelly , Timothy A. McKay

Ongoing and upcoming galaxy surveys are providing precision measurements of galaxy clustering. However a major obstacle in its cosmological application is the stochasticity in the galaxy bias. We explore whether the principal component…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-28 Shuren Zhou , Pengjie Zhang , Ziyang Chen

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

We explore the use of principal component analysis (PCA) to characterize high-fidelity simulations and interferometric observations of the millimeter emission that originates near the horizons of accreting black holes. We show…

Instrumentation and Methods for Astrophysics · Physics 2018-09-05 Lia Medeiros , Tod R. Lauer , Dimitrios Psaltis , Feryal Özel

We introduce a novel method for discerning optical telescope images of stars from those of galaxies using Gaussian processes (GPs). Although applications of GPs often struggle in high-dimensional data modalities such as optical image…

Instrumentation and Methods for Astrophysics · Physics 2022-03-14 Amanda L. Muyskens , Imène R. Goumiri , Benjamin W. Priest , Michael D. Schneider , Robert E. Armstrong , Jason M. Bernstein , Ryan Dana

Eigenmode analysis is one of the most promising methods of analyzing large data sets in ongoing and near-future galaxy surveys. In such analyses, a fast evaluation of the correlation matrix in arbitrary cosmological models is crucial. The…

Astrophysics · Physics 2009-11-10 Takahiko Matsubara , Alexander S. Szalay , Adrian C. Pope

The increasing integration of data science techniques into quantitative finance has enabled more systematic and data-driven approaches to portfolio construction. This paper investigates the use of Principal Component Analysis (PCA) in…

Mathematical Finance · Quantitative Finance 2025-08-22 ZhengXiang Zhou , Yuqi Luan

Dimension-reduction techniques can greatly improve statistical inference in astronomy. A standard approach is to use Principal Components Analysis (PCA). In this work we apply a recently-developed technique, diffusion maps, to astronomical…

Astrophysics · Physics 2011-02-11 Joseph W. Richards , Peter E. Freeman , Ann B. Lee , Chad M. Schafer

From a volume limited sample of 45,542 galaxies and 6,000 groups with $z \leq 0.213$ we use an adapted minimal spanning tree algorithm to identify and classify large scale structures within the Galaxy and Mass Assembly (GAMA) survey. Using…

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