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We employ deep learning (DL) to improve photometric redshifts (photo-$z$s) in the Kilo-Degree Survey Data Release 4 Bright galaxy sample (KiDS-Bright DR4). This dataset, used as a foreground for KiDS lensing and clustering studies, is…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-17 Anjitha John William , Priyanka Jalan , Maciej Bilicki , Wojciech A. Hellwing , Hareesh Thuruthipilly , Szymon J. Nakoneczny

We present an improved photometric redshift estimator code, CuBAN$z$, that is publicly available at https://goo.gl/fpk90V}{https://goo.gl/fpk90V. It uses the back propagation neural network along with clustering of the training set, which…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-23 Saumyadip Samui , Shanoli Samui Pal

The current role of data-driven science is constantly increasing its importance within Astrophysics, due to the huge amount of multi-wavelength data collected every day, characterized by complex and high-volume information requiring…

Instrumentation and Methods for Astrophysics · Physics 2021-04-15 Massimo Brescia , Stefano Cavuoti , Oleksandra Razim , Valeria Amaro , Giuseppe Riccio , Giuseppe Longo

We describe a new method of combining optical and infrared photometry to select Luminous Red Galaxies (LRGs) at redshifts $z > 0.6$. We explore this technique using a combination of optical photometry from CFHTLS and HST, infrared…

Astrophysics of Galaxies · Physics 2015-04-27 Abhishek Prakash , Timothy C. Licquia , Jeffrey A. Newman , Sandhya M. Rao

We present a machine-learning photometric redshift analysis of the Kilo-Degree Survey Data Release 3, using two neural-network based techniques: ANNz2 and MLPQNA. Despite limited coverage of spectroscopic training sets, these ML codes…

We present a photometric method for identifying stars, galaxies and quasars in multi-color surveys and estimating multi-color redshifts for the extragalactic objects. We use a library of >65000 color templates for comparison with observed…

Astrophysics · Physics 2009-10-31 Christian Wolf , Klaus Meisenheimer , Hermann-Josef Röser

We outline how redshift-space distortions (RSD) can be measured from the angular correlation function w({\theta}), of galaxies selected from photometric surveys. The natural degeneracy between RSD and galaxy bias can be minimized by…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Ashley J Ross , Will J Percival , Martin Crocce , Anna Cabre , Enrique Gaztanaga

Accurate photometric redshifts are a lynchpin for many future experiments to pin down the cosmological model and for studies of galaxy evolution. In this study, a novel sparse regression framework for photometric redshift estimation is…

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

Photo-z algorithms that utilize SED template fitting have matured, and are widely adopted for use on high-redshift near-infrared data that provides a unique window into the early universe. Alternative photo-z methods have been developed,…

Instrumentation and Methods for Astrophysics · Physics 2026-02-04 Grant Merz , Ming-Yang Zhuang , Junyao Li , Qian Yang , Yue Shen , Xin Liu , John Franklin Crenshaw

With the dramatic rise in high-quality galaxy data expected from Euclid and Vera C. Rubin Observatory, there will be increasing demand for fast high-precision methods for measuring galaxy fluxes. These will be essential for inferring the…

Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-15 J. Asorey , M. Carrasco Kind , I. Sevilla-Noarbe , R. J. Brunner , J. Thaler

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…

The effective redshift distribution $n(z)$ of galaxies is a critical component in the study of weak gravitational lensing. Here, we introduce a new method for determining $n(z)$ for weak lensing surveys based on high-quality redshifts and…

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing (WL) source galaxies from the Dark Energy Survey Year 1…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-14 M. Gatti , P. Vielzeuf , C. Davis , R. Cawthon , M. M. Rau , J. DeRose , J. De Vicente , A. Alarcon , E. Rozo , E. Gaztanaga , B. Hoyle , R. Miquel , G. M. Bernstein , C. Bonnett , A. Carnero Rosell , F. J. Castander , C. Chang , L. N. da Costa , D. Gruen , J. Gschwend , W. G. Hartley , H. Lin , N. MacCrann , M. A. G. Maia , R. L. C. Ogando , A. Roodman , I. Sevilla-Noarbe , M. A. Troxel , R. H. Wechsler , J. Asorey , T. M. Davis , K. Glazebrook , S. R. Hinton , G. Lewis , C. Lidman , E. Macaulay , A. Möller , C. R. O'Neill , N. E. Sommer , S. A. Uddin , F. Yuan , B. Zhang , T. M. C. Abbott , S. Allam , J. Annis , K. Bechtol , D. Brooks , D. L. Burke , D. Carollo , M. Carrasco Kind , J. Carretero , C. E. Cunha , C. B. D'Andrea , D. L. DePoy , S. Desai , T. F. Eifler , A. E. Evrard , B. Flaugher , P. Fosalba , J. Frieman , J. García-Bellido , D. W. Gerdes , D. A. Goldstein , R. A. Gruendl , G. Gutierrez , K. Honscheid , J. K. Hoormann , B. Jain , D. J. James , M. Jarvis , T. Jeltema , M. W. G. Johnson , M. D. Johnson , E. Krause , K. Kuehn , S. Kuhlmann , N. Kuropatkin , T. S. Li , M. Lima , J. L. Marshall , P. Melchior , F. Menanteau , R. C. Nichol , B. Nord , A. A. Plazas , K. Reil , E. S. Rykoff , M. Sako , E. Sanchez , V. Scarpine , M. Schubnell , E. Sheldon , M. Smith , R. C. Smith , M. Soares-Santos , F. Sobreira , E. Suchyta , M. E. C. Swanson , G. Tarle , D. Thomas , B. E. Tucker , D. L. Tucker , V. Vikram , A. R. Walker , J. Weller , W. Wester , R. C. Wolf

Accurate photo-z measurements are important to construct a large-scale structure map of X-ray Universe in the ongoing SRG/eROSITA All-Sky Survey. We present machine learning Random Forest-based models for probabilistic photo-z predictions…

Instrumentation and Methods for Astrophysics · Physics 2021-07-06 Viktor Borisov , Alex Meshcheryakov , Sergey Gerasimov , RU eROSITA catalog group

The upcoming galaxy large-scale surveys, such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), will generate photometry for billions of galaxies. The interpretation of large-scale weak lensing maps, as well as the…

Instrumentation and Methods for Astrophysics · Physics 2025-10-01 Alvaro Callejas-Tavera , Erik Molino-Minero-Re , Octavio Valenzuela

The availability of large, public, multi-modal astronomical datasets presents an opportunity to execute novel research that straddles the line between science of AI and science of astronomy. Photometric redshift estimation is a…

Instrumentation and Methods for Astrophysics · Physics 2024-02-07 Andrew Engel , Gautham Narayan , Nell Byler

Photometric redshifts (photo-$z$'s) will be crucial for studies of galaxy evolution, large-scale structure, and transients with the Nancy Grace Roman Space Telescope. Deep learning methods leverage pixel-level information from ground-based…

Instrumentation and Methods for Astrophysics · Physics 2026-05-14 Ashod Khederlarian , Brett H. Andrews , Jeffrey A. Newman , Tianqing Zhang , Biprateep Dey

We present a new training set for estimating empirical photometric redshifts of galaxies, which was created as part of the 2dFLenS project. This training set is located in a 700 sq deg area of the KiDS South field and is randomly selected…

Around $10^5$ strongly lensed galaxies are expected to be discovered with Euclid and the LSST. Utilising these large samples to study the inner structure of lens galaxies requires source redshifts, to turn lens models into mass…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-01 Danial Langeroodi , Alessandro Sonnenfeld , Henk Hoekstra , Adriano Agnello