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A serious concern for semi-analytical galaxy formation models, aiming to simulate multi-wavelength surveys and to thoroughly explore the model parameter space, is the extremely time consuming numerical solution of the radiative transfer of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Laura Silva , Fabio Fontanot , Gian Luigi Granato

The next generation of cosmology experiments will be required to use photometric redshifts rather than spectroscopic redshifts. Obtaining accurate and well-characterized photometric redshift distributions is therefore critical for Euclid,…

Instrumentation and Methods for Astrophysics · Physics 2025-06-03 Ibrahim A. Almosallam , Matt J. Jarvis , Stephen J. Roberts

The performance of artificial neural networks (ANNs) is influenced by weight initialization, the nature of activation functions, and their architecture. There is a wide range of activation functions that are traditionally used to train a…

Machine Learning · Statistics 2018-11-30 Saeid Safaei , Vahid Safaei , Solmazi Safaei , Zerotti Woods , Hamid R. Arabnia , Juan B. Gutierrez

The rapid increase in data on galaxy images at low and high redshift calls for re-examination of the classification schemes and for new automatic objective methods. Here we present a classification method by Artificial Neural Networks. We…

Astrophysics · Physics 2007-05-23 Ofer Lahav

In recent years, the increasing popularity of Hi-DPI screens has driven a rising demand for high-resolution images. However, the limited computational power of edge devices poses a challenge in deploying complex super-resolution neural…

Computer Vision and Pattern Recognition · Computer Science 2025-03-10 Yuheng Xu , Shijie Yang , Xin Liu , Jie Liu , Jie Tang , Gangshan Wu

Cosmology and galaxy evolution studies with LSST, \Euclid, and {\it Roman}, will require accurate redshifts for the detected galaxies. In this study, we present improved photometric redshift estimates for galaxies using a template library…

Astrophysics of Galaxies · Physics 2020-08-06 Bomee Lee , Ranga-Ram Chary

We seek to improve the accuracy of joint galaxy photometric redshift estimation and spectral energy distribution (SED) fitting. By simulating different sources of uncorrected systematic errors, we demonstrate that if the uncertainties on…

Instrumentation and Methods for Astrophysics · Physics 2015-06-24 Viviana Acquaviva , Anand Raichoor , Eric Gawiser

In the present study, we use the DES Y3 catalog of LRG to incorporate the realistic galaxies' redshift Probability Distribution Function(PDF) into the correlation function cosmological model. We used four different photo-z estimators ANNz2,…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-06 Paula S. Ferreira , Ribamar R. R. Reis

We introduce Z-Sequence, a novel empirical model that utilises photometric measurements of observed galaxies within a specified search radius to estimate the photometric redshift of galaxy clusters. Z-Sequence itself is composed of a…

Astrophysics of Galaxies · Physics 2021-04-26 Matthew C. Chan , John P. Stott

Recurrent Neural Networks (RNNs) are used in applications that learn dependencies in data sequences, such as speech recognition, human activity recognition, and anomaly detection. In recent years, newer RNN variants, such as GRUs and LSTMs,…

Machine Learning · Computer Science 2022-09-02 Febin Sunny , Mahdi Nikdast , Sudeep Pasricha

We introduce an ordinal classification algorithm for photometric redshift estimation, which significantly improves the reconstruction of photometric redshift probability density functions (PDFs) for individual galaxies and galaxy samples.…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-20 Markus Michael Rau , Stella Seitz , Fabrice Brimioulle , Eibe Frank , Oliver Friedrich , Daniel Gruen , Ben Hoyle

We present a neural network classification (NNC) method for photometric redshift estimation that produces well-calibrated redshift probability density functions (PDFs). The method discretizes the redshift space into ordered bins and…

Astrophysics of Galaxies · Physics 2026-05-08 Da-Chuan Tian , Zhong-Lue Wen , Jun-Qing Xia

The need to analyze the available large synoptic multi-band surveys drives the development of new data-analysis methods. Photometric redshift estimation is one field of application where such new methods improved the results, substantially.…

Instrumentation and Methods for Astrophysics · Physics 2018-01-31 Antonio D'Isanto , Kai Lars Polsterer

The study of the cosmic Dark Ages, Cosmic Dawn, and Epoch of Reionization (EoR) using the all-sky averaged redshifted HI 21cm signal, are some of the key science goals of most of the ongoing or upcoming experiments, for example, EDGES,…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-24 Madhurima Choudhury , Abhirup Datta , Arnab Chakraborty

In order to find a fast and reliable method for selecting metal poor galaxies (MPGs), especially in large surveys and huge database, an Artificial Neural Network (ANN) method is applied to a sample of star-forming galaxies from the Sloan…

Astrophysics of Galaxies · Physics 2015-06-18 F. Shi , Y-Y. Liu , X. Kong , Y. Chen

We present a method, PhotoWeb, for estimating photometric redshifts of individual galaxies, and their equivalent distance, with megaparsec and even sub-megaparsec accuracy using the Cosmic Web as a constraint over photo-z estimates.…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Miguel A. Aragon-Calvo , Rien van de Weygaert , Bernard J. T. Jones , Bahram Mobasher

Determinations of the UV luminosity function of AGN at high redshifts are important for constraining the AGN contribution to reionization and understanding the growth of supermassive black holes. Recent inferences of the luminosity function…

Astrophysics of Galaxies · Physics 2019-06-12 Girish Kulkarni , Gábor Worseck , Joseph F. Hennawi

We describe the construction of MegaZ-LRG, a photometric redshift catalogue of over one million luminous red galaxies (LRGs) in the redshift range 0.4 < z < 0.7 with limiting magnitude i < 20. The catalogue is selected from the imaging data…

Supervised classification is the most active and emerging research trends in today's scenario. In this view, Artificial Neural Network (ANN) techniques have been widely employed and growing interest to the researchers day by day. ANN…

Machine Learning · Computer Science 2019-05-16 Arijit Nandi , Nanda Dulal Jana