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This paper presents a comprehensive study of quasar photometric classification and redshift estimation using machine learning techniques. We cross-matched photometric data from the Dark Energy Survey Data Release 2 (DES DR2) with…

Instrumentation and Methods for Astrophysics · Physics 2026-05-19 Pablo Motta , Filipe B. Abdalla , Elcio Abdalla , Gabriel S. Costa , Camila Cardoso

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

Wide, deep photometric surveys require robust photometric redshift estimates (photo-z's) for studies of large-scale structure. These estimates depend critically on accurate photometry. We describe the improvements to the photometric…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Samuel J. Schmidt , Paul Thorman

In Lima et al. 2008 we presented a new method for estimating the redshift distribution, N(z), of a photometric galaxy sample, using photometric observables and weighted sampling from a spectroscopic subsample of the data. In this paper, we…

Astrophysics · Physics 2010-03-18 Carlos E. Cunha , Marcos Lima , Hiroaki Oyaizu , Joshua Frieman , Huan Lin

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

Broadband photometry offers a time and cost effective method to reconstruct the continuum emission of celestial objects. Thus, photometric redshift estimation has supported the scientific exploitation of extragalactic multiwavelength…

Astrophysics of Galaxies · Physics 2018-10-31 S. Fotopoulou , S. Paltani

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

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…

The development of the state-of-the-art telescopic systems capable of performing expansive sky surveys such as the Sloan Digital Sky Survey, Euclid, and the Rubin Observatory's Legacy Survey of Space and Time (LSST) has significantly…

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 perform an analysis of photometric redshifts estimated by using a non-representative training sets in magnitude space. We use the ANNz2 and GPz algorithms to estimate the photometric redshift both in simulations as well as in real data…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-12 J. D. Rivera , B. Moraes , A. I. Merson , S. Jouvel , F. B. Abdalla , M. C. B Abdalla

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

A variety of fundamental astrophysical science topics require the determination of very accurate photometric redshifts (photo-z's). A wide plethora of methods have been developed, based either on template models fitting or on empirical…

Instrumentation and Methods for Astrophysics · Physics 2016-12-13 Stefano Cavuoti , Valeria Amaro , Massimo Brescia , Civita Vellucci , Crescenzo Tortora , Giuseppe Longo

Emission Line Galaxies (ELGs) are crucial for cosmological studies, particularly in understanding the large-scale structure of the Universe and the role of dark energy. ELGs form an essential component of the target catalogue for the Dark…

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

We propose a Multimodal Machine Learning method for estimating the Photometric Redshifts of quasars (PhotoRedshift-MML for short), which has long been the subject of many investigations. Our method includes two main models, i.e. the feature…

Astrophysics of Galaxies · Physics 2022-11-09 Shuxin Hong , Zhiqiang Zou , A-Li Luo , Xiao Kong , Wenyu Yang , Yanli Chen

We apply a convolutional neural network (CNN) to classify and detect quasars in the Sloan Digital Sky Survey Stripe 82 and also to predict the photometric redshifts of quasars. The network takes the variability of objects into account by…

Instrumentation and Methods for Astrophysics · Physics 2018-04-11 Johanna Pasquet-Itam , Jérôme Pasquet

Accurate photometric redshift (photo-$z$) estimation is a key challenge in cosmology, as uncertainties in photo-$z$ directly limit the scientific return of large-scale structure and weak lensing studies, especially in upcoming Stage IV…

Instrumentation and Methods for Astrophysics · Physics 2025-12-10 Yiming Ren , Kwan Chuen Chan , Le Zhang , Yin Li , Haolin Zhang , Ruiyu Song , Yan Gong , Xian-Min Meng , Xingchen Zhou

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

In this paper we present photometric redshift (photo-$z$) estimates for the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys, currently the most sensitive optical survey covering the majority of the extra-galactic sky. Our…

Astrophysics of Galaxies · Physics 2022-03-14 Kenneth J. Duncan