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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 present a simple, efficient and robust approach to improve cosmological redshift measurements. The method is based on the presence of a reference sample for which a precise redshift number distribution (dN/dz) can be obtained for…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-13 Nicolas Tejos , Aldo Rodriguez-Puebla , Joel R. Primack

Large imaging surveys will rely on photometric redshifts (photo-z's), which are typically estimated through machine learning methods. Currently planned spectroscopic surveys will not be deep enough to produce a representative training…

We present an optimisation method for the assignment of photometric galaxies into a chosen set of redshift bins. This is achieved by combining simulated annealing, an optimisation algorithm inspired by solid-state physics, with an…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-08 Benjamin Stölzner , Benjamin Joachimi , Andreas Korn , the LSST Dark Energy Science Collaboration

We perform a rigorous cosmology analysis on simulated type Ia supernovae (SN~Ia) and evaluate the improvement from including photometric host-galaxy redshifts compared to using only the "zspec" subset with spectroscopic redshifts from the…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Ayan Mitra , Richard Kessler , Surhud More , Renee Hlozek , The LSST Dark Energy Science Collaboration

Proposed cosmological surveys will make use of photometric redshifts of galaxies that are significantly fainter than any complete spectroscopic redshift surveys that exist to train the photo-z methods. We investigate the photo-z biases that…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 C. J. MacDonald , Gary Bernstein

In this work, we derive and calibrate the redshift distribution of the MagLim++ lens galaxy sample used in the Dark Energy Survey Year 6 (DES Y6) 3x2pt cosmology analysis. The 3x2pt analysis combines galaxy clustering from the lens galaxy…

Several papers have recently highlighted the possibility of measuring redshift space distortions from angular auto-correlations of galaxies in photometric redshift bins. In this work we extend this idea to include as observables the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-10 Jacobo Asorey , Martin Crocce , Enrique Gaztanaga

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

A significant challenge facing photometric surveys for cosmological purposes is the need to produce reliable redshift estimates. The estimation of photometric redshifts (photo-zs) has been consolidated as the standard strategy to bypass the…

Accurate and precise photometric redshifts (photo-z's) of Type Ia supernovae (SNe Ia) can enable the use of SNe Ia, measured only with photometry, to probe cosmology. This dramatically increases the science return of supernova surveys…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Yun Wang , E. Gjergo , S. Kuhlmann

Photometric redshift estimation plays a crucial role in modern cosmological surveys for studying the universe's large-scale structures and the evolution of galaxies. Deep learning has emerged as a powerful method to produce accurate…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-04 R. Ait-Ouahmed , S. Arnouts , J. Pasquet , M. Treyer , E. Bertin

Forming a three dimensional view of the Universe is a long-standing goal of astronomical observations, and one that becomes increasingly difficult at high redshift. In this paper we discuss how tomography of the intergalactic medium (IGM)…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-12 Marcel Schmittfull , Martin White

This paper reports the results obtained on the photometric redshifts measurement and accuracy, and cluster tomography in the ESO Distant Cluster Survey (EDisCS) fields. Photometric redshifts were computed using two independent codes (Hyperz…

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

The current role of data-driven science is constantly increasing its importance within Astrophysics, due to the huge amount of multi-wavelength data collected every day, characterized by complex and high-volume information requiring…

Instrumentation and Methods for Astrophysics · Physics 2021-04-15 Massimo Brescia , Stefano Cavuoti , Oleksandra Razim , Valeria Amaro , Giuseppe Riccio , Giuseppe Longo

We conduct a detailed analysis of the photometric redshift requirements for the proposed Dark Energy Survey (DES) using two sets of mock galaxy simulations and an artificial neural network code - ANNz. In particular, we examine how optical…

Astrophysics · Physics 2010-03-26 Manda Banerji , Filipe B. Abdalla , Ofer Lahav , Huan Lin

We describe a new method of combining optical and infrared photometry to select Luminous Red Galaxies (LRGs) at redshifts $z > 0.6$. We explore this technique using a combination of optical photometry from CFHTLS and HST, infrared…

Astrophysics of Galaxies · Physics 2015-04-27 Abhishek Prakash , Timothy C. Licquia , Jeffrey A. Newman , Sandhya M. Rao

With the dramatic rise in high-quality galaxy data expected from Euclid and Vera C. Rubin Observatory, there will be increasing demand for fast high-precision methods for measuring galaxy fluxes. These will be essential for inferring the…

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