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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

We report a significant detection of weak, tangential distortion of the images of cosmologically distant, faint galaxies due to gravitational lensing by foreground galaxies. A mean image polarisation of $<p>=0.011\pm 0.006$ is measured for…

Astrophysics · Physics 2016-08-30 Tereasa Brainerd , Roger Blandford , Ian Smail

This paper follows series of our works on the applicability of various machine learning methods to the morphological galaxy classification (Vavilova et al., 2021, 2022). We exploited the sample of 315776 SDSS DR9 galaxies with absolute…

We present GALARIO, a computational library that exploits the power of modern graphical processing units (GPUs) to accelerate the analysis of observations from radio interferometers like ALMA or the VLA. GALARIO speeds up the computation of…

Instrumentation and Methods for Astrophysics · Physics 2018-03-14 Marco Tazzari , Frederik Beaujean , Leonardo Testi

We propose a new technique to directly measure the shapes of dark matter halos of galaxies using weak gravitational lensing. Extending the standard galaxy-galaxy lensing method, we show that the shape parameters of the mass distribution of…

Astrophysics · Physics 2009-10-31 Priyamvada Natarajan , Alexandre Refregier

We develop a model independent, robust method for determining galaxy rotation velocities across a 2D array of spaxels from an integral field spectrograph. Simulations demonstrate the method is accurate down to lower spectral signal-to-noise…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-02 Mikhail Denissenya , Eric V. Linder , Sangwoo Park , Arman Shafieloo , Satadru Bag

Here we report on a set of programs developed at the ZMBH Bio-Imaging Facility for tracking real-life images of cellular processes. These programs perform 1) automated tracking; 2) quantitative and comparative track analyses of different…

Biological Physics · Physics 2017-03-09 Aliakbar Jafarpour , Holger Lorenz

Luminosity profiles of galaxies acting as strong gravitational lenses can be tricky to study. Indeed, strong gravitational lensing images display several lensed components, both point-like and diffuse, around the lensing galaxy. Those…

Astrophysics of Galaxies · Physics 2015-12-23 J. Biernaux , P. Magain , D. Sluse , V. Chantry

Traditional photometric redshift methods use only color information about the objects in question to estimate their redshifts. This paper introduces a new method utilizing colors, luminosity, surface brightness, and radial light profile to…

Astrophysics · Physics 2008-11-26 James J. Wray , James E. Gunn

The generalized density is a product of a density function and a weight function. For example, the average local brightness of an astronomical image is the probability of finding a galaxy times the mean brightness of the galaxy. We propose…

Methodology · Statistics 2014-06-10 Yen-Chi Chen , Christopher R. Genovese , Larry Wasserman

Line detection is a classic and essential problem in image processing, computer vision and machine intelligence. Line detection has many important applications, including image vectorization (e.g., document recognition and art design),…

Computer Vision and Pattern Recognition · Computer Science 2025-01-09 Liping Yang , Joshua Driscol , Ming Gong , Katie Slack , Wenbin Zhang , Shujie Wang , Catherine G. Potts

Gravitational lensing is the deflection of light rays due to the gravity of intervening masses. This phenomenon is observed in a variety of scales and configurations, involving any non-uniform mass such as planets, stars, galaxies, clusters…

Data mining techniques, including clustering and classification tasks, for the automatic information extraction from large datasets are increasingly demanded in several scientific fields. In particular, in the astrophysical field, large…

Astrophysics · Physics 2015-06-24 M. Frailis , A. De Angelis , V. Roberto

We propose a new technique, which we call the lens parallax method, to determine simultaneously the redshift distribution of the faint blue galaxies and the mass distributions of foreground clusters of galaxies. The method is based on…

Astrophysics · Physics 2009-10-28 Matthias Bartelmann , Ramesh Narayan

We present GalSBI, a phenomenological model of the galaxy population for cosmological applications using simulation-based inference. The model is based on analytical parametrizations of galaxy luminosity functions, morphologies and spectral…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-09 Silvan Fischbacher , Tomasz Kacprzak , Luca Tortorelli , Beatrice Moser , Alexandre Refregier , Patrick Gebhardt , Daniel Gruen

At high redshift, due to both observational limitations and the variety of galaxy morphologies in the early universe, measuring galaxy structure can be challenging. Non-parametric measurements such as the CAS system have thus become an…

Astrophysics of Galaxies · Physics 2021-09-08 C. Tohill , L. Ferreira , C. J. Conselice , S. P. Bamford , F. Ferrari

State-of-the-art galaxy formation simulations generate data within weeks or months. Their results consist of a random sub-sample of possible galaxies with a fixed number of stars. We propose a ML based method, GalacticFlow, that generalizes…

Astrophysics of Galaxies · Physics 2023-12-12 Luca Wolf , Tobias Buck

Gaia mission will offer an exceptional opportunity to perform variability studies. The data homogeneity, its optimised photometric systems, composed of 11 medium and 4-5 broad bands, the high photometric precision in G band of one milli-mag…

Astrophysics · Physics 2007-05-23 Laurent Eyer

Galaxies grow and evolve in dark matter halos. Because dark matter is not visible, galaxies' halo masses ($\rm{M}_{\rm{halo}}$) must be inferred indirectly. We present a graph neural network (GNN) model for predicting $\rm{M}_{\rm{halo}}$…

Astrophysics of Galaxies · Physics 2024-11-20 Nikhil Garuda , John F. Wu , Dylan Nelson , Annalisa Pillepich

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