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We present Galaxy Zoo DECaLS: detailed visual morphological classifications for Dark Energy Camera Legacy Survey images of galaxies within the SDSS DR8 footprint. Deeper DECaLS images (r=23.6 vs. r=22.2 from SDSS) reveal spiral arms, weak…

The stochastic order redshift technique (SORT) is a simple, efficient, and robust method to improve cosmological redshift measurements. The method relies upon having a small ($\sim$10 per cent) reference sample of high-quality redshifts.…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-25 James Kakos , Joel R. Primack , Aldo Rodriguez-Puebla , Nicolas Tejos , L. Y. Aaron Yung , Rachel S. Somerville

We examine the impact of using photometric redshifts for studying the evolution of both the global galaxy luminosity function (LF) and that for different galaxy types. To this end we compare LFs obtained using photometric redshifts from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 B. H. F. Ramos , P. S. Pellegrini , C. Benoist , L. N. da Costa , M. A. G. Maia , M. Makler , R. L. C. Ogando , F. de Simoni , A. A. Mesquita

Four large-area Sunyaev-Zeldovich (SZ) experiments -- APEX-SZ, SPT, ACT, and Planck -- promise to detect clusters of galaxies through the distortion of Cosmic Microwave Background photons by hot (> 10^6 K) cluster gas (the SZ effect) over…

The cosmological redshift of a galaxy's light is inferable from its observable properties in images. Because imaging is much easier to acquire than spectroscopic observations that would allow the identification of distinct line features,…

Instrumentation and Methods for Astrophysics · Physics 2026-05-11 Luca Tortorelli , Daniel Grün

Context. Strong lensing mass measurements require the knowledge of the redshift of both the lens and the source galaxy. Traditionally, spectroscopic redshifts are used for this purpose. Upcoming surveys, however, will lead to the discovery…

Astrophysics of Galaxies · Physics 2022-04-15 Alessandro Sonnenfeld

Machine learning techniques offer a plethora of opportunities in tackling big data within the astronomical community. We present the set of Generalized Linear Models as a fast alternative for determining photometric redshifts of galaxies, a…

Instrumentation and Methods for Astrophysics · Physics 2016-06-29 J. Elliott , R. S. de Souza , A. Krone-Martins , E. Cameron , E. E. O. Ishida , J. Hilbe

Around $10^5$ strongly lensed galaxies are expected to be discovered with Euclid and the LSST. Utilising these large samples to study the inner structure of lens galaxies requires source redshifts, to turn lens models into mass…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-01 Danial Langeroodi , Alessandro Sonnenfeld , Henk Hoekstra , Adriano Agnello

We present a new set of photometric transformations for red stars observed with the Sloan Digital Sky Survey (SDSS) 0.5-m Photometric Telescope (PT) and the SDSS 2.5-m telescope at the Apache Point Observatory in New Mexico. Nightly PT…

This paper explores the application of machine learning methods for classifying astronomical sources using photometric data, including normal and emission line galaxies (ELGs; starforming, starburst, AGN, broad line), quasars, and stars. We…

At the core of the standard cosmological model lies the assumption that the redshift of distant galaxies is independent of photon wavelength. This invariance of cosmological redshift with wavelength is routinely found in all galaxy spectra…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-20 I. Ferreras , I. Trujillo

Using the newly available infrared images of the Hubble Deep Field in the J, H, and K bands and an optimal photometric method, we have refined a technique to estimate the redshifts of 1067 galaxies. A detailed comparison of our results with…

Astrophysics · Physics 2009-10-30 A. Fernandez-Soto , K. M. Lanzetta , A. Yahil

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 XMM Cluster Archive Super Survey (X-CLASS) is a serendipitously-detected X-ray-selected sample of 845 galaxy clusters based on 2774 XMM archival observations and covering approximately 90 deg$^2$ spread across the high-Galactic latitude…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-12 J. Ridl , N. Clerc , T. Sadibekova , L. Faccioli , F. Pacaud , J. Greiner , T. Krühler , A. Rau , M. Salvato , M. -L. Menzel , H. Steinle , P. Wiseman , K. Nandra , J. Sanders

The morphological diversity of galaxies is a relevant probe of galaxy evolution and cosmological structure formation, but the classification of galaxies in large sky surveys is becoming a significant challenge. We use data from the…

We investigate the accuracy of 4000\AA/Balmer-break based redshifts by combining Hubble Space Telescope ({\it HST}) grism data with photometry. The grism spectra are from the Probing Evolution And Reionization Spectroscopically (PEARS)…

Astrophysics of Galaxies · Physics 2019-10-09 Bhavin A. Joshi , Seth Cohen , Rogier A. Windhorst , Rolf Jansen , Norbert Pirzkal , Nimish P. Hathi

In the next decade, the LSST will become a major facility for the astronomical community. However accurately determining the redshifts of the observed galaxies without using spectroscopy is a major challenge. Reconstruction of the redshifts…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Alexia Gorecki , Alexandra Abate , Réza Ansari , Aurélien Barrau , Sylvain Baumont , Marc Moniez , Jean-Stéphane Ricol

We present the first identification of large-scale structures (LSS) at z $< 1.1$ in the Cosmic Evolution Survey (COSMOS). The structures are identified from adaptive smoothing of galaxy counts in the pseudo-3d space ($\alpha,\delta$,z)…

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 multi-band optical and near-infrared photometric observations of galaxies in the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) to predict photometric redshifts using artificial neural networks. The…

Astrophysics of Galaxies · Physics 2020-01-15 Derek Wilson , Hooshang Nayyeri , Asantha Cooray , Boris Häußler
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