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The accurate estimation of photometric redshifts is crucial to many upcoming galaxy surveys, for example the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). Almost all Rubin extragalactic and cosmological science requires…

Instrumentation and Methods for Astrophysics · Physics 2022-05-04 Natalia Stylianou , Alex I. Malz , Peter Hatfield , John Franklin Crenshaw , Julia Gschwend

Galaxy cross-correlations with high-fidelity redshift samples hold the potential to precisely calibrate systematic photometric redshift uncertainties arising from the unavailability of complete and representative training and validation…

We derive a simple empirical photometric redshift estimator using a training set of galaxies with multiband photometry and measured redshifts in the Hubble Deep Field (HDF). This estimator is model-independent; it does not use spectral…

Astrophysics · Physics 2007-05-23 Yun Wang , Neta Bahcall , Edwin L. Turner

A new approach to estimating photometric redshifts - using Artificial Neural Networks (ANNs) - is investigated. Unlike the standard template-fitting photometric redshift technique, a large spectroscopically-identified training set is…

Astrophysics · Physics 2009-11-07 Andrew E. Firth , Ofer Lahav , Rachel S. Somerville

Estimating redshift is a central task in astrophysics, but its measurement is costly and time-consuming. In addition, current image-based methods are often validated on homogeneous datasets. The development and comparison of networks able…

Instrumentation and Methods for Astrophysics · Physics 2026-03-17 Alessandro Meroni , Nicolò Oreste Pinciroli Vago , Piero Fraternali

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

Evaluating the accuracy and calibration of the redshift posteriors produced by photometric redshift (photo-z) estimators is vital for enabling precision cosmology and extragalactic astrophysics with modern wide-field photometric surveys.…

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))…

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

Precision photometric redshifts will be essential for extracting cosmological parameters from the next generation of wide-area imaging surveys. In this paper we introduce a photometric redshift algorithm, ArborZ, based on the…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-06 David W. Gerdes , Adam J. Sypniewski , Timothy A. McKay , Jiangang Hao , Matthew R. Weis , Risa H. Wechsler , Michael T. Busha

We use the deepest and most complete redshift catalog currently available (the Hubble Deep Field (HDF) North supplemented by new HDF South redshift data) to minimize residuals between photometric and spectroscopic redshift estimates. The…

Astrophysics · Physics 2016-08-30 M. Massarotti , A. Iovino , A. Buzzoni , D. Valls--Gabaud

We use the deepest and the most comprehensive photometric data currently available for GOODS-South galaxies to measure their photometric redshifts. The photometry includes VLT/VIMOS (U-band), HST/ACS (F435W, F606W, F775W, and F850LP bands),…

The use of photometric redshifts in cosmology is increasing. Often, however these photo-zs are treated like spectroscopic observations, in that the peak of the photometric redshift, rather than the full probability density function (PDF),…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Adam D Myers , Martin White , Nicholas M. Ball

We investigate the impact of photometric signal-to-noise (S/N) on the precision of photometric redshifts in multi-band imaging surveys, using both simulations and real data. We simulate the optical 4-band (BVRz) Deep Lens Survey (DLS,…

Astrophysics · Physics 2009-11-13 V. E. Margoniner , D. M. Wittman

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 ANNz2, a new implementation of the public software for photometric redshift (photo-z) estimation of Collister and Lahav (2004), which now includes generation of full probability distribution functions (PDFs). ANNz2 utilizes…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-24 Iftach Sadeh , Filipe B. Abdalla , Ofer Lahav

Future radio surveys will generate catalogues of tens of millions of radio sources, for which redshift estimates will be essential to achieve many of the science goals. However, spectroscopic data will be available for only a small fraction…

Instrumentation and Methods for Astrophysics · Physics 2019-09-11 Ray P. Norris , M. Salvato , G. Longo , M. Brescia , T. Budavari , S. Carliles , S. Cavuoti , D. Farrah , J. Geach , K. Luken , A. Musaeva , K. Polsterer , G. Riccio , N. Seymour , V. Smolčić , M. Vaccari , P. Zinn

Aims: We present a custom support vector machine classification package for photometric redshift estimation, including comparisons with other methods. We also explore the efficacy of including galaxy shape information in redshift…

Instrumentation and Methods for Astrophysics · Physics 2017-04-12 Evan Jones , J. Singal

The estimation of spectroscopic and photometric redshifts (spec-z and photo-z) is crucial for future cosmological surveys. It can directly affect several powerful measurements of the Universe, e.g. weak lensing and galaxy clustering. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-05 Xingchen Zhou , Yan Gong , Xian-Min Meng , Xin Zhang , Ye Cao , Xuelei Chen , Valeria Amaro , Zuhui Fan , Liping Fu

In this paper we present and characterize a nearest-neighbors color-matching photometric redshift estimator that features a direct relationship between the precision and accuracy of the input magnitudes and the output photometric redshifts.…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-20 Melissa L. Graham , Andrew J. Connolly , Željko Ivezić , Samuel J. Schmidt , R. Lynne Jones , Mario Jurić , Scott F. Daniel , Peter Yoachim