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Given an approximately centered image of a spiral galaxy, we describe an entirely automated method that finds, centers, and sizes the galaxy and then automatically extracts structural information about the spiral arms. For each arm segment…

Astrophysics of Galaxies · Physics 2015-06-18 Darren R. Davis , Wayne B. Hayes

Photometry of galaxies has typically focused on small, faint systems due to their interest for cosmological studies. Large angular size galaxies, on the other hand, offer a more detailed view into the properties of galaxies, but bring a…

Astrophysics · Physics 2007-05-23 J. Schombert

We developed a Python based framework for astronomical image processing and analysis. Astronomical image loading, normalizing, stacking, and filtering processes represent visible range images from grayscale. Besides, the blending process…

Instrumentation and Methods for Astrophysics · Physics 2024-10-10 Tanmoy Bhowmik , MD Fardin Islam , Kazi Nusrat Tasneem , Rantideb Roy , Rownok Shahariar

Cosmological galaxy formation simulations are powerful tools to understand the complex processes that govern the formation and evolution of galaxies. However, evaluating the realism of these simulations remains a challenge. The two common…

Quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. But galaxy morphological classification is still mainly done visually by dedicated…

We present a method to simulate deep sky images, including realistic galaxy morphologies and telescope characteristics. To achieve a wide diversity of simulated galaxy morphologies, we first use the shapelets formalism to parametrize the…

Image simulations are essential tools for preparing and validating the analysis of current and future wide-field optical surveys. However, the galaxy models used as the basis for these simulations are typically limited to simple parametric…

Instrumentation and Methods for Astrophysics · Physics 2021-05-12 Francois Lanusse , Rachel Mandelbaum , Siamak Ravanbakhsh , Chun-Liang Li , Peter Freeman , Barnabas Poczos

We describe an extension of the halo-based galaxy group-finding algorithm. We add freedom to the algorithm in order to more accurately determine which galaxies are central and which are satellites, and to provide unbiased estimates of halo…

Astrophysics of Galaxies · Physics 2020-07-27 Jeremy L. Tinker

We present a new scheme, $\it{galtag}$, for refining the photometric redshift measurements of faint galaxies by probabilistically tagging them to observed galaxy groups constructed from a brighter, magnitude-limited spectroscopy survey.…

Astrophysics of Galaxies · Physics 2018-07-04 P. R. Kafle , A. S. G. Robotham , S. P. Driver , S. Deeley , P. Norberg , M. J. Drinkwater , L. J. Davies

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

Gravitational lensing has now become a popular tool to measure the mass distribution of structures in the Universe on various scales. Here we focus on the study of galaxy's scale dark matter halos with galaxy-galaxy lensing techniques:…

Astrophysics · Physics 2007-05-23 M. Limousin , J-P. Kneib , P. Natarajan

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 present GASPHOT, a tool for automated surface photometry and morphological classification of galaxies in deep and wide fields. The requirements for any such tool are reviewed, and its use for the classification of high-z galaxies is…

Astrophysics · Physics 2007-05-23 E. Pignatelli , G. Fasano

Modern sky surveys produce vast amounts of observational data, making the application of classical methods for estimating galaxy properties challenging and time-consuming. This challenge can be significantly alleviated by employing…

Astrophysics of Galaxies · Physics 2025-09-17 Olena Torbaniuk , Lars Doorenbos , Maurizio Paolillo , Stefano Cavuoti , Massimo Brescia , Giuseppe Longo

We describe a simple and fast method to correct ellipticity measurements of galaxies from the distortion by the instrumental and atmospheric point spread function (PSF), in view of weak lensing shear measurements. The method performs a…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-01 M. Tewes , N. Cantale , F. Courbin , T. D. Kitching , G. Meylan

Synthesizer is a fast, flexible, modular, and extensible Python package that empowers astronomers to turn theoretical galaxy models into realistic synthetic observations - including spectra, photometry, images, and spectral cubes - with a…

We describe a system for the automatic quantification of structure in spiral galaxies. This enables translation of sky survey images into data needed to help address fundamental astrophysical questions such as the origin of spiral…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-04 Darren Davis , Wayne Hayes

We present a two-dimensional (2-D) fitting algorithm (GALFIT, Version 3) with new capabilities to study the structural components of galaxies and other astronomical objects in digital images. Our technique improves on previous 2-D fitting…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Chien Y. Peng , Luis C. Ho , Chris D. Impey , Hans-Walter Rix

One of the major challenges in astronomy involves accurately classifying galaxies, particularly distinguishing between different galaxy types. While many complex algorithms have shown strong performance in classification tasks, their…

Instrumentation and Methods for Astrophysics · Physics 2026-03-13 Sazatul Nadhilah Zakaria , Santtosh Muniyandy , John Y. H. Soo

We present Synthesizer, a fast, flexible, modular and extensible platform for modelling synthetic astrophysical observables. Synthesizer can be used for a number of applications, but is predominantly designed for generating mock observables…

Instrumentation and Methods for Astrophysics · Physics 2025-10-14 Christopher C. Lovell , William J. Roper , Aswin P. Vijayan , Stephen M. Wilkins , Sophie Newman , Louise Seeyave