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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 report the first analytical expression purely constructed by a machine to determine photometric redshifts ($z_{\rm phot}$) of galaxies. A simple and reliable functional form is derived using $41,214$ galaxies from the Sloan Digital Sky…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 A. Krone-Martins , E. E. O. Ishida , R. S. de Souza

The luminosity functions of galaxies and quasars provide invaluable information about galaxy and quasar formation. Estimating the luminosity function from magnitude limited samples is relatively straightforward, provided that the distances…

Astrophysics · Physics 2008-11-26 Ravi K. Sheth

We present a neural network based approach to the determination of photometric redshift. The method was tested on the Sloan Digital Sky Survey Early Data Release (SDSS-EDR) reaching an accuracy comparable and, in some cases, better than SED…

Quickly growing computing facilities and an increasing number of extragalactic observations encourage the application of data-driven approaches to uncover hidden relations from astronomical data. In this work we raise the problem of…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-25 A. Elyiv , O. Melnyk , I. Vavilova , D. Dobrycheva , V. Karachentseva

Estimating redshifts from broadband photometry is often limited by how accurately we can map the colors of galaxies to an underlying spectral template. Current techniques utilize spectrophotometric samples of galaxies or spectra derived…

Instrumentation and Methods for Astrophysics · Physics 2025-03-11 John Franklin Crenshaw , Andrew J. Connolly

Current and future weak lensing surveys will rely on photometrically estimated redshifts of very large numbers of galaxies. In this paper, we address several different aspects of the demanding photo-z performance that will be required for…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Rongmon Bordoloi , Simon J. Lilly , Adam Amara

Determining the redshift distribution $n(z)$ of galaxy samples is essential for several cosmological probes including weak lensing. For imaging surveys, this is usually done using photometric redshifts estimated on an object-by-object…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-31 Jörg Herbel , Tomasz Kacprzak , Adam Amara , Alexandre Refregier , Claudio Bruderer , Andrina Nicola

We seek to improve the accuracy of joint galaxy photometric redshift estimation and spectral energy distribution (SED) fitting. By simulating different sources of uncorrected systematic errors, we demonstrate that if the uncertainties on…

Instrumentation and Methods for Astrophysics · Physics 2015-06-24 Viviana Acquaviva , Anand Raichoor , Eric Gawiser

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

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

Photometric redshift (photo-z) is a fundamental parameter for multi-wavelength photometric surveys, while galaxy clusters are important cosmological probers and ideal objects for exploring the dense environmental impact on galaxy evolution.…

Astrophysics of Galaxies · Physics 2022-06-01 Hu Zou , Jipeng Sui , Suijian Xue , Xu Zhou , Jun Ma , Zhimin Zhou , Jundan Nie , Tianmeng Zhang , Lu Feng , Zhixia Shen , Jiali Wang

We calculate photometric redshifts from the Sloan Digital Sky Survey Main Galaxy Sample, The Galaxy Evolution Explorer All Sky Survey, and The Two Micron All Sky Survey using two new training-set methods. We utilize the broad-band…

Astrophysics · Physics 2008-11-26 M. J. Way , A. N. Srivastava

With the advent of deep, all-sky radio surveys, the need for ancillary data to make the most of the new, high-quality radio data from surveys like the Evolutionary Map of the Universe (EMU), GLEAM-X, VLASS and LoTSS is growing rapidly.…

Instrumentation and Methods for Astrophysics · Physics 2023-07-13 Kieran J. Luken , Ray P. Norris , X. Rosalind Wang , Laurence A. F. Park , Ying Guo , Miroslav D. Filipovic

We develop a new method which measures the projected density distribution w_p(r_p)n of photometric galaxies surrounding a set of spectroscopically-identified galaxies, and simultaneously the projected correlation function w_p(r_p) between…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Wenting Wang , Y. P. Jing , Cheng Li , Teppei Okumura , Jiaxin Han

We present zephyr, a novel method that integrates cutting-edge normalizing flow techniques into a mixture density estimation framework, enabling the effective use of heterogeneous training data for photometric redshift inference. Compared…

Instrumentation and Methods for Astrophysics · Physics 2023-11-01 Zechang Sun , Joshua S. Speagle , Song Huang , Yuan-Sen Ting , Zheng Cai

We present results of using individual galaxies' redshift probability information derived from a photometric redshift (photo-z) algorithm, SPIDERz, to identify potential catastrophic outliers in photometric redshift determinations. By using…

Astrophysics of Galaxies · Physics 2019-11-07 Evan Jones , J. Singal

In this paper we explore the applicability of the unsupervised machine learning technique of Self Organizing Maps (SOM) to estimate galaxy photometric redshift probability density functions (PDFs). This technique takes a spectroscopic…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 M. Carrasco Kind , R. J. Brunner

Computing photo-z for AGN is challenging, primarily due to the interplay of relative emissions associated with the SMBH and its host galaxy. SED fitting methods, effective in pencil-beam surveys, face limitations in all-sky surveys with…

Over the past 30 years, numerous large-scale photometric astronomical surveys have been conducted, including SDSS, Pan-STARRS, Gaia,2MASS, WISE, and others. These surveys provide extensive photometric measurements that can be used to infer…

Instrumentation and Methods for Astrophysics · Physics 2025-11-03 Mateusz Kapusta