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Our aim in this work is to answer, using simulated narrow-band photometry data, the following general question: What can we learn about galaxies from these new generation cosmological surveys? For instance, can we estimate stellar age and…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-29 William Schoenell , Roberto Cid Fernandes , Narciso Benítez , Natalia Vale Asari

Star formation rates (SFRs) are a crucial observational tracer of galaxy formation and evolution. Spectroscopy, which is expensive, is traditionally used to estimate SFRs. This study tests the possibility of inferring SFRs of large samples…

Astrophysics of Galaxies · Physics 2024-10-10 Satvik Raghav , Prasanth Ayitapu , Sathwik Narkedimilli , Sujith Makam , Aswath Babu H

The use of machine learning is becoming ubiquitous in astronomy, but remains rare in the study of the atmospheres of exoplanets. Given the spectrum of an exoplanetary atmosphere, a multi-parameter space is swept through in real time to find…

Earth and Planetary Astrophysics · Physics 2018-06-12 Pablo Marquez-Neila , Chloe Fisher , Raphael Sznitman , Kevin Heng

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

Photometric redshifts will be a key data product for the Rubin Observatory Legacy Survey of Space and Time (LSST) as well as for future ground and space-based surveys. The need for photometric redshifts, or photo-zs, arises from sparse…

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

Photometric wide-field surveys are imaging the sky in unprecedented detail. These surveys face a significant challenge in efficiently estimating galactic photometric redshifts while accurately quantifying associated uncertainties. In this…

The Physics of the Accelerating Universe (PAU) survey at the William Herschel Telescope (WHT) will use a new optical camera (PAUCam) with a large set of narrow-band filters to perform a photometric galaxy survey with a quasi-spectroscopic…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-06 Pol Martí , Ramon Miquel , Francisco J. Castander , Enrique Gaztañaga , Martin Eriksen , Carles Sánchez

We present a method for accurately and precisely inferring photometric dust extinction towards stars at mid-to-high Galactic latitudes using probabilistic machine learning to model the colour-magnitude distribution of zero-extinction stars…

Astrophysics of Galaxies · Physics 2025-12-15 Matthew O'Callaghan , Kaisey S. Mandel , Gerry Gilmore

The next generation of large scale imaging surveys (such as those conducted with the Large Synoptic Survey Telescope and Euclid) will require accurate photometric redshifts in order to optimally extract cosmological information. Gaussian…

Astrophysics of Galaxies · Physics 2018-01-24 Zahra Gomes , Matt J. Jarvis , Ibrahim A. Almosallam , Stephen J. Roberts

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 propose a Multimodal Machine Learning method for estimating the Photometric Redshifts of quasars (PhotoRedshift-MML for short), which has long been the subject of many investigations. Our method includes two main models, i.e. the feature…

Astrophysics of Galaxies · Physics 2022-11-09 Shuxin Hong , Zhiqiang Zou , A-Li Luo , Xiao Kong , Wenyu Yang , Yanli Chen

Based on the SDSS and SDSS-WISE quasar datasets, we put forward two schemes to estimate the photometric redshifts of quasars. Our schemes are based on the idea that the samples are firstly classified into subsamples by a classifier and then…

Instrumentation and Methods for Astrophysics · Physics 2019-12-05 Yanxia Zhang , Jingyi Zhang , Xin Jin , Yongheng Zhao

We calculate the observable properties of the most massive high-redshift galaxies in the hierarchical formation scenario where stellar spheroid and supermassive black hole growth are fueled by gas-rich mergers. Combining high-resolution…

Astrophysics · Physics 2010-11-05 Brant Robertson , Yuexing Li , Thomas J. Cox , Lars Hernquist , Philip F. Hopkins

The third version of the XMM-Newton serendipitous catalogue (3XMM), containing almost half million sources, is now the largest X-ray catalogue. However, its full scientific potential remains untapped due to the lack of distance information…

Astrophysics of Galaxies · Physics 2018-10-17 A. Ruiz , A. Corral , G. Mountrichas , I. Georgantopoulos

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

(Abridged) In this paper we present photometric redshift estimates for a sample of X-ray selected sources detected in the wide field (~2 deg^2), bright [f_{X} (0.5-8 keV)~10^{-14} cgs] XMM-Newton/2dF survey. Unlike deeper X-ray samples…

Astrophysics · Physics 2008-11-26 S. Kitsionas , E. Hatziminaoglou , A. Georgakakis , I. Georgantopoulos

In the modern galaxy surveys photometric redshifts play a central role in a broad range of studies, from gravitational lensing and dark matter distribution to galaxy evolution. Using a dataset of about 25,000 galaxies from the second data…

Instrumentation and Methods for Astrophysics · Physics 2017-06-14 Stefano Cavuoti , Crescenzo Tortora , Massimo Brescia , Giuseppe Longo , Mario Radovich , Nicola R. Napolitano , Valeria Amaro , Civita Vellucci

The accurate estimation of photometric redshifts plays a crucial role in accomplishing science objectives of the large survey projects. The template-fitting and machine learning are the two main types of methods applied currently. Based on…

Photometric redshifts (photo-$z$'s) are crucial for the cosmology, galaxy evolution, and transient science drivers of next-generation imaging facilities like the Euclid Mission, the Rubin Observatory, and the Nancy Grace Roman Space…

Astrophysics of Galaxies · Physics 2025-12-03 Emma R. Moran , Brett H. Andrews , Jeffrey A. Newman , Biprateep Dey