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We present a determination of the effects of including galaxy morphological parameters in photometric redshift estimation with an artificial neural network method. Neural networks, which recognize patterns in the information content of data…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 J. Singal , M. Shmakova , B. Gerke , R. L. Griffith , J. Lotz

Photometric redshift estimation algorithms are often based on representative data from observational campaigns. Data-driven methods of this type are subject to a number of potential deficiencies, such as sample bias and incompleteness.…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-06 Nesar Ramachandra , Jonás Chaves-Montero , Alex Alarcon , Arindam Fadikar , Salman Habib , Katrin Heitmann

We conduct a comprehensive study of the effects of incorporating galaxy morphology information in photometric redshift estimation. Using machine learning methods, we assess the changes in the scatter and catastrophic outlier fraction of…

We present and compare in this paper new photometric redshift catalogs of the galaxies in three public fields: the NTT Deep Field, the HDF-N and the HDF-S. Photometric redshifts have been obtained for thewhole sample, by adopting a $\chi^2$…

Astrophysics · Physics 2009-10-31 A. Fontana , S. D'Odorico , F. Poli , E. Giallongo , S. Arnouts , S. Cristiani , A. Moorwood , P. Saracco

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 present a structure finding algorithm designed to identify galaxy groups in photometric redshift data sets: the probability friends-of-friends (pFoF) algorithm. This algorithm is derived by combining the friends-of-friends algorithm in…

Astrophysics · Physics 2009-11-13 I-hui Li , Howard K. C. Yee

We apply instance-based machine learning in the form of a k-nearest neighbor algorithm to the task of estimating photometric redshifts for 55,746 objects spectroscopically classified as quasars in the Fifth Data Release of the Sloan Digital…

We analyze MegaZ-LRG, a photometric-redshift catalogue of Luminous Red Galaxies (LRGs) based on the imaging data of the Sloan Digital Sky Survey (SDSS) 4th Data Release. MegaZ-LRG, presented in a companion paper, contains 10^6 photometric…

Astrophysics · Physics 2009-05-29 Chris Blake , Adrian Collister , Sarah Bridle , Ofer Lahav

We present a dataset built for machine learning applications consisting of galaxy photometry, images, spectroscopic redshifts, and structural properties. This dataset comprises 286,401 galaxy images and photometry from the Hyper-Suprime-Cam…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 Tuan Do , Bernie Boscoe , Evan Jones , Yun Qi Li , Kevin Alfaro

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

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

In this work the random forest algorithm GALPRO is implemented to generate photometric redshift posteriors, and its performance when trained and then applied to data from another survey is investigated. The algorithm is initially calibrated…

Astrophysics of Galaxies · Physics 2024-07-31 Lara Janiurek , Martin A. Hendry , Fiona C. Speirits

We present a supervised neural network approach to the determination of photometric redshifts. The method was tuned to match the characteristics of the Sloan Digital Sky Survey and it exploits the spectroscopic redshifts provided by this…

We present and describe a catalog of galaxy photometric redshifts (photo-z's) for the Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6). We use the Artificial Neural Network (ANN) technique to calculate photo-z's and the Nearest Neighbor…

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

We estimated photometric redshifts (zphot) for more than 1.1 million galaxies of the ESO Public Kilo-Degree Survey (KiDS) Data Release 2. KiDS is an optical wide-field imaging survey carried out with the VLT Survey Telescope (VST) and the…

We discuss the construction of a photometric redshift catalogue of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS), emphasizing the principal steps necessary for constructing such a catalogue -- (i) photometrically…

The formally exact framework of equilibrium Density Functional Theory (DFT) is capable of simultaneously and consistently describing thermodynamic and structural properties of interacting many-body systems in arbitrary external potentials.…

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…

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 describe a multi-component matched filter cluster confirmation tool (MCMF) designed for the study of large X-ray source catalogs produced by the upcoming X-ray all-sky survey mission eROSITA. We apply the method to confirm a sample of 88…

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