English
Related papers

Related papers: Photometric redshifts for the Kilo-Degree Survey. …

200 papers

Determining photometric redshifts to high accuracy is paramount to measure distances in wide-field cosmological experiments. With only photometric information at hand, photo-zs are prone to systematic uncertainties in the intervening…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-16 Z. Ansari , A. Agnello , C. Gall

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 use the overlap between multiband photometry of the Kilo-Degree Survey (KiDS) and spectroscopic data based on the Sloan Digital Sky Survey (SDSS) and Galaxy And Mass Assembly (GAMA) to infer the colour-magnitude relation of red-sequence…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-13 Mohammadjavad Vakili , Maciej Bilicki , Henk Hoekstra , Nora Elisa Chisari , Christos Georgiou , Arun Kannawadi , Koen Kuijken , Angus H. Wright

We present a catalogue of galaxy photometric redshifts and k-corrections for the Sloan Digital Sky Survey Seven Data Release (SDSS-DR7), available on the World Wide Web. The photometric redshifts were estimated with an artificial neural…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Ana Laura O'Mill , Fernanda Duplancic , Diego García Lambas , Laerte Sodré

Photometric galaxy surveys are an essential tool to further our understanding of the large-scale structure of the universe, its matter and energy content and its evolution. These surveys necessitate the determination of the galaxy redshifts…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-06 Pol Martí , Ramon Miquel , Anne Bauer , Enrique Gaztañaga

In order to retrieve cosmological parameters from photometric surveys, we need to estimate the distribution of the photometric redshift in the sky with excellent accuracy. We use and apply three different machine learning methods to…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-13 Elcio Abdalla , Filipe B. Abdalla , Alessandro Marins , Amilcar Queiroz , Rafael M. Ribeiro , Alex S. C. Souza

We introduce ANNz, a freely available software package for photometric redshift estimation using Artificial Neural Networks. ANNz learns the relation between photometry and redshift from an appropriate training set of galaxies for which the…

Astrophysics · Physics 2009-08-21 Adrian A. Collister , Ofer Lahav

Current and future imaging surveys require photometric redshifts (photo-zs) to be estimated for millions of galaxies. Improving the photo-z quality is a major challenge but is needed to advance our understanding of cosmology. In this paper…

Instrumentation and Methods for Astrophysics · Physics 2023-03-22 L. Cabayol , M. Eriksen , J. Carretero , R. Casas , F. J. Castander , E. Fernández , J. Garcia-Bellido , E. Gaztanaga , H. Hildebrandt , H. Hoekstra , B. Joachimi , R. Miquel , C. Padilla , A. Pocino , E. Sanchez , S. Serrano , I. Sevilla , M. Siudek , P. Tallada-Crespí , N. Aghanim , A. Amara , N. Auricchio , M. Baldi , R. Bender , D. Bonino , E. Branchini , M. Brescia , J. Brinchmann , S. Camera , V. Capobianco , C. Carbone , M. Castellano , S. Cavuoti , A. Cimatti , R. Cledassou , G. Congedo , C. J. Conselice , L. Conversi , Y. Copin , L. Corcione , F. Courbin , M. Cropper , A. Da Silva , H. Degaudenzi , M. Douspis , F. Dubath , C. A. J. Duncan , X. Dupac , S. Dusini , S. Farrens , P. Fosalba , M. Frailis , E. Franceschi , P. Franzetti , B. Garilli , W. Gillard , B. Gillis , C. Giocoli , A. Grazian , F. Grupp , S. V. H. Haugan , W. Holmes , F. Hormuth , A. Hornstrup , P. Hudelot , K. Jahnke , M. Kümme , S. Kermiche , A. Kiessling , M. Kilbinger , R. Kohley , H. Kurki-Suonio , S. Ligori , P. B. Lilje , I. Lloro , E. Maiorano , O. Mansutti , O. Marggraf , K. Markovic , F. Marulli , R. Massey , M. Meneghetti , E. Merlin , G. Meylan , M. Moresco , L. Moscardini , E. Munari , R. Nakajima , S. M. Niemi , S. Paltani , F. Pasian , K. Pedersen , V. Pettorino , G. Polenta , M. Poncet , L. Popa , L. Pozzetti , F. Raison , R. Rebolo , J. Rhodes , G. Riccio , C. Rosset , E. Rossetti , R. Saglia , B. Sartoris , P. Schneider , A. Secroun , G. Seide , C. Sirignano , G. Sirri , L. Stanco , A. N. Taylor , I. Tereno , R. Toledo-Moreo , F. Torradeflot , I. Tutusaus , E. Valentijn , L. Valenziano , Y. Wang , J. Weller , G. Zamorani , J. Zoubian , S. Andreon , S. Mei , V. Scottez , A. Tramacere

(Abridged) In this paper we present photometric redshift estimates for a sample of X-ray selected sources detected in the wide field (~2 deg^2), bright [f_{X} (0.5-8 keV)~10^{-14} cgs] XMM-Newton/2dF survey. Unlike deeper X-ray samples…

Astrophysics · Physics 2008-11-26 S. Kitsionas , E. Hatziminaoglou , A. Georgakakis , I. Georgantopoulos

We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Coadd Data. We use the Artificial Neural Network (ANN) technique to calculate photo-z's and the Nearest Neighbor Error…

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 calculate photometric redshifts from the Sloan Digital Sky Survey Data Release 2 Galaxy Sample using artificial neural networks (ANNs). Different input patterns based on various parameters (e.g. magnitude, color index, flux information)…

Astrophysics · Physics 2007-05-23 Lili Li , Yanxia Zhang , Yongheng Zhao , Dawei Yang

The accuracy of galaxy photometric redshift (photo-$z$) can significantly affect the analysis of weak gravitational lensing measurements, especially for future high-precision surveys. In this work, we try to extract photo-$z$ information…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-11 Xingchen Zhou , Yan Gong , Xian-Min Meng , Ye Cao , Xuelei Chen , Zhu Chen , Wei Du , Liping Fu , Zhijian Luo

In this paper we introduce the \textsc{Deepz} deep learning photometric redshift (photo-$z$) code. As a test case, we apply the code to the PAU survey (PAUS) data in the COSMOS field. \textsc{Deepz} reduces the $\sigma_{68}$ scatter…

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…

Proposed cosmological surveys will make use of photometric redshifts of galaxies that are significantly fainter than any complete spectroscopic redshift surveys that exist to train the photo-z methods. We investigate the photo-z biases that…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 C. J. MacDonald , Gary Bernstein

Quasar photometric redshifts are essential for studying cosmology and large-scale structures. However, their complex spectral energy distributions cause significant redshift-color degeneracy, limiting the accuracy of traditional methods. To…

Astrophysics of Galaxies · Physics 2025-12-19 Jianzhen Chen , Zhijian Luo , Liping Fu , Zhu Chen , Hubing Xiao , Shaohua Zhang , Chenggang Shu

We present a robust method to estimate the redshift of galaxies using Pan-STARRS1 photometric data. Our method is an adaptation of the one proposed by Beck et al. (2016) for the SDSS Data Release 12. It uses a training set of 2313724…

Astrophysics of Galaxies · Physics 2020-10-14 Paula Tarrío , Stefano Zarattini

With the launch of eROSITA (extended Roentgen Survey with an Imaging Telescope Array), successfully occurred on 2019 July 13, we are facing the challenge of computing reliable photometric redshifts for 3 million of active galactic nuclei…

Instrumentation and Methods for Astrophysics · Physics 2019-09-04 M. Brescia , M. Salvato , S. Cavuoti , T. T. Ananna , G. Riccio , S. M. LaMassa , C. M. Urry , G. Longo