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Related papers: Photometric Redshifts with Copula Entropy

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We construct a set of model spectra specifically designed to match the colours of the BOSS CMASS galaxies and to be used with photometric redshift template fitting techniques. As a basis we use a set of spectral energy distributions (SEDs)…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-08 N. Greisel , S. Seitz , N. Drory , R. Bender , R. P. Saglia , J. Snigula

A measurement of the redshift drift constitutes a model-independent probe of fundamental cosmology. Several approaches are being considered to make the necessary observations, using (i) the Extremely Large Telescope (ELT), (ii) the Cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-13 Fulvio Melia

Improving distance measurements in large imaging surveys is a major challenge to better reveal the distribution of galaxies on a large scale and to link galaxy properties with their environments. Photometric redshifts can be efficiently…

In this paper, we address the problem of spectroscopic redshift estimation in Astronomy. Due to the expansion of the Universe, galaxies recede from each other on average. This movement causes the emitted electromagnetic waves to shift from…

Instrumentation and Methods for Astrophysics · Physics 2019-08-27 Radamanthys Stivaktakis , Grigorios Tsagkatakis , Bruno Moraes , Filipe Abdalla , Jean-Luc Starck , Panagiotis Tsakalides

Combining visual observations of SR variables with measurements of them using a photoelectric photometer is discussed then demonstrated using data obtained for the bright, southern SR variable theta Aps. Combining such observations is…

Astrophysics · Physics 2007-12-03 T. T. Moon , S. A. Otero , L. L. Kiss

A tomographic method, aiming at probing velocity fields at depth in stellar atmospheres, is applied to the red supergiant star {\mu} Cep and to snapshots of 3D radiative-hydrodynamics simulation in order to constrain atmospheric motions and…

Solar and Stellar Astrophysics · Physics 2020-02-19 K. Kravchenko , A. Chiavassa , S. Van Eck , A. Jorissen , T. Merle , B. Freytag

By means of CCD photometry in three bands (Gunn g, r, i) we investigate the existence of 12 candidate clusters extracted via a model independent peak finding algorithm (\cite{memsait}) from DPOSS data. The derived color-magnitude diagrams…

Astrophysics · Physics 2009-11-07 E. Puddu , S. Andreon , G. Longo , V. Strazzullo , M. Paolillo , R. Gal

We use an empirical approach to characterize the effect of charge-transfer efficiency (CTE) losses in images taken with the Wide-Field Channel of the Advanced Camera for Surveys. The study is based on profiles of warm pixels in 168 dark…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Jay Anderson , Luigi R. Bedin

Current cosmological analyses which use Type Ia supernova (SN Ia) observations combine SN samples to expand the redshift range beyond that of a single sample and increase the overall sample size. The inhomogeneous photometric calibration…

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

We release photometric redshifts, reaching $\sim$0.7, for $\sim$14M galaxies at $r\leq 20$ in the 11,500 deg$^2$ of the SDSS north and south galactic caps. These estimates were inferred from a convolution neural network (CNN) trained on…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-16 M. Treyer , R. Ait-Ouahmed , J. Pasquet , S. Arnouts , E. Bertin , D. Fouchez

Given multiband photometric data from the SDSS DR6, we estimate galaxy redshifts. We employ a Random Forest trained on color features and spectroscopic redshifts from 80,000 randomly chosen primary galaxies yielding a mapping from color to…

The cosmological redshift phenomenon can be described by the dark matter field fluid model, the results deduced from this model agree very well with the observations. The observed cosmological redshift of light depends on both the speed of…

General Physics · Physics 2007-05-23 Hongjun Pan

The Baire metric induces an ultrametric on a dataset and is of linear computational complexity, contrasted with the standard quadratic time agglomerative hierarchical clustering algorithm. We apply the Baire distance to spectrometric and…

Information Retrieval · Computer Science 2017-08-23 Fionn Murtagh , Pedro Contreras

The Chinese Space Station Optical Survey (CSS-OS) is a major science project of the Space Application System of the China Manned Space Program. This survey is planned to perform both photometric imaging and slitless spectroscopic…

Instrumentation and Methods for Astrophysics · Physics 2018-08-23 Ye Cao , Yan Gong , Xian-Min Meng , Cong K. Xu , Xuelei Chen , Qi Guo , Ran Li , Dezi Liu , Yongquan Xue , Li Cao , Xiyang Fu , Xin Zhang , Shen Wang , Hu Zhan

We estimate the sensitivity of future galaxy surveys to cosmological parameters, using the redshift dependent angular power spectra of galaxy number counts, $C_\ell(z_1,z_2)$, calculated with all relativistic corrections at first order in…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-04 Enea Di Dio , Francesco Montanari , Ruth Durrer , Julien Lesgourgues

Photometric redshifts (photo-z's) provide an alternative way to estimate the distances of large samples of galaxies and are therefore crucial to a large variety of cosmological problems. Among the various methods proposed over the years,…

Instrumentation and Methods for Astrophysics · Physics 2017-06-13 Stefano Cavuoti , Massimo Brescia , Valeria Amaro , Civita Vellucci , Giuseppe Longo , Crescenzo Tortora

Our group has developed a technique that makes use of the observed non-linear relation between the ultraviolet and the X-ray luminosity in quasars to provide an independent measurement of their distances, thus turning quasars into…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-05 Elisabeta Lusso
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