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Photometric redshifts play an important role as a measure of distance for various cosmological topics. Spectroscopic redshifts are only available for a very limited number of objects but can be used for creating statistical models. A broad…

Instrumentation and Methods for Astrophysics · Physics 2016-08-30 Kai Lars Polsterer , Antonio D'Isanto , Fabian Gieseke

Photometric redshifts (photo-z's) provide an alternative way to estimate the distances of large samples of galaxies and are therefore crucial to a large variety of cosmological problems. Among the various methods proposed over the years,…

Instrumentation and Methods for Astrophysics · Physics 2017-06-13 Stefano Cavuoti , Massimo Brescia , Valeria Amaro , Civita Vellucci , Giuseppe Longo , Crescenzo Tortora

We train a deep residual convolutional neural network (CNN) to predict the gas-phase metallicity ($Z$) of galaxies derived from spectroscopic information ($Z \equiv 12 + \log(\rm O/H)$) using only three-band $gri$ images from the Sloan…

Astrophysics of Galaxies · Physics 2019-03-04 John F. Wu , Steven Boada

The multi-band HSC-CLAUDS survey comprises several sky regions with varying observing conditions, only one of which, the COSMOS Ultra Deep Field (UDF), offers extensive redshift coverage. We aim to exploit a complete sample of labeled…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-11 M. Treyer , R. Ait-Ouahmed , S. Arnouts , J. Pasquet , E. Bertin , G. Desprez , V. Picouet , M. Sawicki

Accurate estimation of photometric redshifts (photo-$z$s) is crucial for cosmological surveys. Various methods have been developed for this purpose, such as template fitting methods and machine learning techniques, each with its own…

The scientific value of the next generation of large continuum surveys would be greatly increased if the redshifts of the newly detected sources could be rapidly and reliably estimated. Given the observational expense of obtaining…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 S. J. Curran , J. P. Moss , Y. C. Perrott

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

We investigate and demonstrate the use of convolutional neural networks (CNNs) for the task of distinguishing between merging and non-merging galaxies in simulated images, and for the first time at high redshifts (i.e. $z=2$). We extract…

Astrophysics of Galaxies · Physics 2020-04-28 A. Ćiprijanović , G. F. Snyder , B. Nord , J. E. G. Peek

We present our results from training and evaluating a convolutional neural network (CNN) to predict galaxy shapes from wide-field survey images of the first data release of the Dark Energy Survey (DES DR1). We use conventional shape…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 Dezső Ribli , László Dobos , István Csabai

Over the years, photometric redshift estimation (photo-z) has advanced through various methods. This study evaluates four distinct photo-z estimators-ANNz2, BPZ, ENF, and DNF-using the Dark Energy Survey Y3 BAO Sample. Unlike most studies,…

Astrophysics of Galaxies · Physics 2025-07-08 Paula S. Ferreira , Ribamar R. R. Reis

We present a photometric redshift (photo-$z$) estimation technique for galaxies in the P\lowercase{an}-STARRS1 (PS1) $3\pi $ survey. Specifically, we train and test a regression and a classification Random-Forest (RF) models using…

Astrophysics of Galaxies · Physics 2021-05-28 A. Baldeschi , M. Stroh , R. Margutti , T. Laskar , A. Miller

Wide field images taken in several photometric bands allow simultaneous measurement of redshifts for thousands of galaxies. A variety of algorithms to make this measurement have appeared in the last few years, the majority of which can be…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-11 Juan De Vicente , Eusebio Sánchez , Ignacio Sevilla

We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based photometric redshift methods -- ANNZ2, BPZ…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-07 C. Bonnett , M. A. Troxel , W. Hartley , A. Amara , B. Leistedt , M. R. Becker , G. M. Bernstein , S. Bridle , C. Bruderer , M. T. Busha , M. Carrasco Kind , M. J. Childress , F. J. Castander , C. Chang , M. Crocce , T. M. Davis , T. F. Eifler , J. Frieman , C. Gangkofner , E. Gaztanaga , K. Glazebrook , D. Gruen , T. Kacprzak , A. King , J. Kwan , O. Lahav , G. Lewis , C. Lidman , H. Lin , N. MacCrann , R. Miquel , C. R. O'Neill , A. Palmese , H. V. Peiris , A. Refregier , E. Rozo , E. S. Rykoff , I. Sadeh , C. Sánchez , E. Sheldon , S. Uddin , R. H. Wechsler , J. Zuntz , T. Abbott , F. B. Abdalla , S. Allam , R. Armstrong , M. Banerji , A. H. Bauer , A. Benoit-Lévy , E. Bertin , D. Brooks , E. Buckley-Geer , D. L. Burke , D. Capozzi , A. Carnero Rosell , J. Carretero , C. E. Cunha , C. B. D'Andrea , L. N. da Costa , D. L. DePoy , S. Desai , H. T. Diehl , J. P. Dietrich , P. Doel , A. Fausti Neto , E. Fernandez , B. Flaugher , P. Fosalba , D. W. Gerdes , R. A. Gruendl , K. Honscheid , B. Jain , D. J. James , M. Jarvis , A. G. Kim , K. Kuehn , N. Kuropatkin , T. S. Li , M. Lima , M. A. G. Maia , M. March , J. L. Marshall , P. Martini , P. Melchior , C. J. Miller , E. Neilsen , R. C. Nichol , B. Nord , R. Ogando , A. A. Plazas , K. Reil , A. K. Romer , A. Roodman , M. Sako , E. Sanchez , B. Santiago , R. C. Smith , M. Soares-Santos , F. Sobreira , E. Suchyta , M. E. C. Swanson , G. Tarle , J. Thaler , D. Thomas , V. Vikram , A. R. Walker

We measure photometric redshifts and spectral types for galaxies in the COSMOS survey. We use template fitting technique combined with luminosity function priors and with the option to simultaneously estimate dust extinction (i.e. E(B-V))…

In this work, we studied the impact of galaxy morphology on photometric redshift (photo-$z$) probability density functions (PDFs). By including galaxy morphological parameters like the radius, axis-ratio, surface brightness and the S\'ersic…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-09 John Y. H. Soo , Benjamin Joachimi

The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the $z'$ and $R_c$ bands for ~90 square degrees of sky, and supplemental $V$ and $B$ data have been obtained for 33.6 deg$^{2}$. We compile a…

Astrophysics · Physics 2009-11-10 B. C. Hsieh , H. K. C. Yee , H. Lin , M. D. Gladders

Noisy distance estimates associated with photometric rather than spectroscopic redshifts lead to a mis-estimate of the luminosities, and produce a correlated mis-estimate of the sizes. We consider a sample of early-type galaxies from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Graziano Rossi , Ravi K. Sheth , Changbom Park

Given multiband photometric data from the SDSS DR6, we estimate galaxy redshifts. We employ a Random Forest trained on color features and spectroscopic redshifts from 80,000 randomly chosen primary galaxies yielding a mapping from color to…

We present an empirical method for estimating the underlying redshift distribution N(z) of galaxy photometric samples from photometric observables. The method does not rely on photometric redshift (photo-z) estimates for individual…

Astrophysics · Physics 2008-11-26 Marcos Lima , Carlos E. Cunha , Hiroaki Oyaizu , Joshua Frieman , Huan Lin , Erin S. Sheldon