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Related papers: Deriving Photometric Redshifts using Fuzzy Archety…

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In a companion paper, we proposed combining large numbers of "fuzzy archetypes" with Self-Organizing Maps (SOMs) to derive photometric redshifts in a data-driven way. In this paper, we investigate the performance of several sampling…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-29 Joshua S. Speagle , Daniel J. Eisenstein

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

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 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 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

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.…

The upcoming galaxy large-scale surveys, such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), will generate photometry for billions of galaxies. The interpretation of large-scale weak lensing maps, as well as the…

Instrumentation and Methods for Astrophysics · Physics 2025-10-01 Alvaro Callejas-Tavera , Erik Molino-Minero-Re , Octavio Valenzuela

Photometric redshifts are estimated on the basis of template scenarios with the help of the code ZPEG, an extension of the galaxy evolution model PEGASE.2 and available on the PEGASE web site. The spectral energy distribution (SED)…

Astrophysics · Physics 2009-11-07 Damien Le Borgne , Brigitte Rocca-Volmerange

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

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

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 present a novel approach to photometric redshifts, one that merges the advantages of both the template fitting and empirical fitting algorithms, without any of their disadvantages. This technique derives a set of templates, describing…

Astrophysics · Physics 2009-10-31 I. Csabai , A. J. Connolly , A. S. Szalay , T. Budavari

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

Characterization of the redshift distribution of ensembles of galaxies is pivotal for large scale structure cosmological studies. In this work, we focus on improving the Self-Organizing Map (SOM) methodology for photometric redshift…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-05 A. Campos , B. Yin , S. Dodelson , A. Amon , A. Alarcon , C. Sánchez , G. M. Bernstein , G. Giannini , J. Myles , S. Samuroff , O. Alves , F. Andrade-Oliveira , K. Bechtol , M. R. Becker , J. Blazek , H. Camacho , A. Carnero Rosell , M. Carrasco Kind , R. Cawthon , C. Chang , R. Chen , A. Choi , J. Cordero , C. Davis , J. DeRose , H. T. Diehl , C. Doux , A. Drlica-Wagner , K. Eckert , T. F. Eifler , J. Elvin-Poole , S. Everett , X. Fang , A. Ferté , O. Friedrich , M. Gatti , D. Gruen , R. A. Gruendl , I. Harrison , W. G. Hartley , K. Herner , H. Huang , E. M. Huff , M. Jarvis , E. Krause , N. Kuropatkin , P. -F. Leget , N. MacCrann , J. McCullough , A. Navarro-Alsina , S. Pandey , J. Prat , M. Raveri , R. P. Rollins , A. Roodman , R. Rosenfeld , A. J. Ross , E. S. Rykoff , J. Sanchez , L. F. Secco , I. Sevilla-Noarbe , E. Sheldon , T. Shin , M. A. Troxel , I. Tutusaus , T. N. Varga , R. H. Wechsler , B. Yanny , Y. Zhang , J. Zuntz , M. Aguena , J. Annis , D. Bacon , S. Bocquet , D. Brooks , D. L. Burke , J. Carretero , F. J. Castander , M. Costanzi , L. N. da Costa , J. De Vicente , P. Doel , I. Ferrero , B. Flaugher , J. Frieman , J. García-Bellido , E. Gaztanaga , G. Gutierrez , S. R. Hinton , D. L. Hollowood , K. Honscheid , D. J. James , K. Kuehn , M. Lima , H. Lin , J. L. Marshall , J. Mena-Fernández , F. Menanteau , R. Miquel , R. L. C. Ogando , M. Paterno , M. E. S. Pereira , A. Pieres , A. A. Plazas Malagón , A. Porredon , E. Sanchez , D. Sanchez Cid , M. Smith , E. Suchyta , M. E. C. Swanson , G. Tarle , C. To , V. Vikram , N. Weaverdyck

We introduce an ordinal classification algorithm for photometric redshift estimation, which significantly improves the reconstruction of photometric redshift probability density functions (PDFs) for individual galaxies and galaxy samples.…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-20 Markus Michael Rau , Stella Seitz , Fabrice Brimioulle , Eibe Frank , Oliver Friedrich , Daniel Gruen , Ben Hoyle

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…

We present a novel method capable of creating optimal eigenspectra from multicolor redshift surveys for photometric redshift estimation. Our iterative training algorithm modifies the templates to represent the photometric measurements…

I present a new approach at deriving far-infrared photometric redshifts for galaxies based on their reprocessed emission from dust at rest-frame far-infrared through millimeter wavelengths. Far-infrared photometric redshifts ("FIR-$z$")…

Astrophysics of Galaxies · Physics 2020-09-09 Caitlin M. Casey
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