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Related papers: Co-SOM: Co-training for photometric redshift estim…

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We present an unsupervised machine learning approach that can be employed for estimating photometric redshifts. The proposed method is based on a vector quantization approach called Self--Organizing Mapping (SOM). A variety of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 M. J. Way , C. D. Klose

We introduce a framework for the enhanced estimation of photometric redshifts using Self-Organising Maps (SOMs). Our method projects galaxy Spectral Energy Distributions (SEDs) onto a two-dimensional map, identifying regions that are…

We present an application of unsupervised machine learning - the self-organised map (SOM) - as a tool for visualising, exploring and mining the catalogues of large astronomical surveys. Self-organisation culminates in a low-resolution…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 James E. Geach

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

Accurate photometric redshift calibration is central to the robustness of all cosmology constraints from cosmic shear surveys. Analyses of the KiDS re-weighted training samples from all overlapping spectroscopic surveys to provide a direct…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Angus H. Wright , Hendrik Hildebrandt , Jan Luca van den Busch , Catherine Heymans

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 present a method to refine photometric redshift galaxy catalogs by comparing their color-space matching with overlapping spectroscopic calibration data. We focus on cases where photometric redshifts (photo-$z$) are estimated empirically.…

In order to answer the open questions of modern cosmology and galaxy evolution theory, robust algorithms for calculating photometric redshifts (photo-z) for very large samples of galaxies are needed. Correct estimation of the various…

Instrumentation and Methods for Astrophysics · Physics 2021-08-25 Oleksandra Razim , Stefano Cavuoti , Massimo Brescia , Giuseppe Riccio , Mara Salvato , Giuseppe Longo

Spectroscopic datasets are essential for training and calibrating photometric redshift (photo-$z$) methods. However, spectroscopic redshifts (spec-$z$'s) constitute a biased and sparse sampling of the photometric galaxy population, which…

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

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

Calibrating the photometric redshifts of >10^9 galaxies for upcoming weak lensing cosmology experiments is a major challenge for the astrophysics community. The path to obtaining the required spectroscopic redshifts for training and…

Knowing the redshift of galaxies is one of the first requirements of many cosmological experiments, and as it's impossible to perform spectroscopy for every galaxy being observed, photometric redshift (photo-z) estimations are still of…

Instrumentation and Methods for Astrophysics · Physics 2022-03-09 Ben Henghes , Connor Pettitt , Jeyan Thiyagalingam , Tony Hey , Ofer Lahav

The Euclid survey aims to trace the evolution of cosmic structures up to redshift $z$ $\sim$ 3 and beyond. Its success depends critically on obtaining highly accurate mean redshifts for ensembles of galaxies $n(z)$ in all tomographic bins,…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-18 W. Roster , A. H. Wright , H. Hildebrandt , R. Reischke , O. Ilbert , W. d'Assignies D. , M. Manera , M. Bolzonella , D. C. Masters , S. Paltani , W. G. Hartley , Y. Kang , H. Hoekstra , B. Altieri , A. Amara , S. Andreon , N. Auricchio , C. Baccigalupi , M. Baldi , A. Balestra , S. Bardelli , P. Battaglia , R. Bender , A. Biviano , E. Branchini , M. Brescia , S. Camera , G. Cañas-Herrera , V. Capobianco , C. Carbone , V. F. Cardone , J. Carretero , R. Casas , S. Casas , F. J. Castander , M. Castellano , G. Castignani , S. Cavuoti , K. C. Chambers , A. Cimatti , C. Colodro-Conde , G. Congedo , C. J. Conselice , L. Conversi , Y. Copin , A. Costille , F. Courbin , H. M. Courtois , M. Cropper , A. Da Silva , H. Degaudenzi , S. de la Torre , G. De Lucia , F. Dubath , C. A. J. Duncan , X. Dupac , S. Dusini , S. Escoffier , M. Farina , R. Farinelli , S. Farrens , F. Faustini , S. Ferriol , F. Finelli , P. Fosalba , N. Fourmanoit , M. Frailis , E. Franceschi , M. Fumana , S. Galeotta , K. George , W. Gillard , B. Gillis , C. Giocoli , J. Gracia-Carpio , A. Grazian , F. Grupp , S. V. H. Haugan , W. Holmes , F. Hormuth , A. Hornstrup , P. Hudelot , K. Jahnke , M. Jhabvala , B. Joachimi , E. Keihänen , S. Kermiche , B. Kubik , H. Kurki-Suonio , A. M. C. Le Brun , D. Le Mignant , S. Ligori , P. B. Lilje , V. Lindholm , I. Lloro , D. Maino , E. Maiorano , O. Mansutti , O. Marggraf , M. Martinelli , N. Martinet , F. Marulli , R. J. Massey , E. Medinaceli , S. Mei , M. Melchior , Y. Mellier , M. Meneghetti , E. Merlin , G. Meylan , A. Mora , M. Moresco , L. Moscardini , R. Nakajima , C. Neissner , S. -M. Niemi , C. Padilla , F. Pasian , K. Pedersen , V. Pettorino , S. Pires , G. Polenta , M. Poncet , L. A. Popa , L. Pozzetti , F. Raison , R. Rebolo , A. Renzi , J. Rhodes , G. Riccio , E. Romelli , M. Roncarelli , C. Rosset , E. Rossetti , R. Saglia , Z. Sakr , D. Sapone , B. Sartoris , M. Schirmer , P. Schneider , T. Schrabback , M. Scodeggio , A. Secroun , E. Sefusatti , G. Seidel , S. Serrano , P. Simon , C. Sirignano , G. Sirri , J. Skottfelt , L. Stanco , J. Steinwagner , P. Tallada-Crespí , A. N. Taylor , H. I. Teplitz , I. Tereno , N. Tessore , S. Toft , R. Toledo-Moreo , F. Torradeflot , I. Tutusaus , L. Valenziano , J. Valiviita , T. Vassallo , G. Verdoes Kleijn , A. Veropalumbo , Y. Wang , J. Weller , G. Zamorani , F. M. Zerbi , E. Zucca , C. Burigana , L. Gabarra , C. Porciani , V. Scottez , M. Sereno

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

Obtaining accurate photometric redshift estimations is an important aspect of cosmology, remaining a prerequisite of many analyses. In creating novel methods to produce redshift estimations, there has been a shift towards using machine…

Instrumentation and Methods for Astrophysics · Physics 2021-07-07 Ben Henghes , Connor Pettitt , Jeyan Thiyagalingam , Tony Hey , Ofer Lahav

In the era of huge astronomical surveys, machine learning offers promising solutions for the efficient estimation of galaxy properties. The traditional, `supervised' paradigm for the application of machine learning involves training a model…

Astrophysics of Galaxies · Physics 2022-12-21 A. Humphrey , P. A. C. Cunha , A. Paulino-Afonso , S. Amarantidis , R. Carvajal , J. M. Gomes , I. Matute , P. Papaderos

We propose a method to substantially increase the flexibility and power of template fitting-based photometric redshifts by transforming a large numbers of galaxy spectral templates into a corrresponding collection of "fuzzy archetypes"…

Astrophysics of Galaxies · Physics 2015-10-29 Joshua S. Speagle , Daniel J. Eisenstein

There has been an increasing interest in semi-supervised learning in the recent years because of the great number of datasets with a large number of unlabeled data but only a few labeled samples. Semi-supervised learning algorithms can work…

Machine Learning · Computer Science 2020-03-26 Pedro H. M. Braga , Hansenclever F. Bassani
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