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We present a novel way of using neural networks (NN) to estimate the redshift distribution of a galaxy sample. We are able to obtain a probability density function (PDF) for each galaxy using a classification neural network. The method is…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-08 Christopher Bonnett

MiniJPAS is a ~1 deg^2 imaging survey of the AEGIS field in 60 bands, performed to demonstrate the scientific potential of the upcoming JPAS survey. Full coverage of the 3800-9100 \AA range with 54 narrow and 6 broad optical filters allow…

When analyzing galaxy clustering in multi-band imaging surveys, there is a trade-off between selecting the largest galaxy samples (to minimize the shot noise) and selecting samples with the best photometric redshift (photo-z) precision,…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-07 Dimitrios Tanoglidis , Chihway Chang , Joshua Frieman

Photometric galaxy surveys constitute a powerful cosmological probe but rely on the accurate characterization of their redshift distributions using only broadband imaging, and can be very sensitive to incomplete or biased priors used for…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-30 Alex Alarcon , Carles Sánchez , Gary M. Bernstein , Enrique Gaztañaga

We perform a systematic analysis of the effects of photometric redshift uncertainties on weak lensing tomography. We describe the photo-z distribution with a bias and Gaussian scatter that are allowed to vary arbitrarily between intervals…

Astrophysics · Physics 2009-11-13 Zhaoming Ma , Wayne Hu , Dragan Huterer

Three-dimensional wide-field galaxy surveys are fundamental for cosmological studies. For higher redshifts (z > 1.0), where galaxies are too faint, quasars still trace the large-scale structure of the Universe. Since available telescope…

Instrumentation and Methods for Astrophysics · Physics 2022-09-21 Sándor Kunsági-Máté , Róbert Beck , István Szapudi , István Csabai

Weak gravitational lensing is a valuable probe of galaxy formation and cosmology. Here we quantify the effects of using photometric redshifts (photo-z) in galaxy-galaxy lensing, for both sources and lenses, both for the immediate goal of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 R. Nakajima , R. Mandelbaum , U. Seljak , J. D. Cohn , R. Reyes , R. Cool

We present a technique for the estimation of photometric redshifts based on feed-forward neural networks. The Multilayer Perceptron (MLP) Artificial Neural Network is used to predict photometric redshifts in the HDF-S from an ultra deep…

Most LSST extragalactic science will rely on photometric redshifts (photo-$z$) to extract distance information for the galaxies. However, an incomplete or non-representative training set can introduce bias into photo-$z$ estimation. It is…

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing (WL) source galaxies from the Dark Energy Survey Year 1…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-14 M. Gatti , P. Vielzeuf , C. Davis , R. Cawthon , M. M. Rau , J. DeRose , J. De Vicente , A. Alarcon , E. Rozo , E. Gaztanaga , B. Hoyle , R. Miquel , G. M. Bernstein , C. Bonnett , A. Carnero Rosell , F. J. Castander , C. Chang , L. N. da Costa , D. Gruen , J. Gschwend , W. G. Hartley , H. Lin , N. MacCrann , M. A. G. Maia , R. L. C. Ogando , A. Roodman , I. Sevilla-Noarbe , M. A. Troxel , R. H. Wechsler , J. Asorey , T. M. Davis , K. Glazebrook , S. R. Hinton , G. Lewis , C. Lidman , E. Macaulay , A. Möller , C. R. O'Neill , N. E. Sommer , S. A. Uddin , F. Yuan , B. Zhang , T. M. C. Abbott , S. Allam , J. Annis , K. Bechtol , D. Brooks , D. L. Burke , D. Carollo , M. Carrasco Kind , J. Carretero , C. E. Cunha , C. B. D'Andrea , D. L. DePoy , S. Desai , T. F. Eifler , A. E. Evrard , B. Flaugher , P. Fosalba , J. Frieman , J. García-Bellido , D. W. Gerdes , D. A. Goldstein , R. A. Gruendl , G. Gutierrez , K. Honscheid , J. K. Hoormann , B. Jain , D. J. James , M. Jarvis , T. Jeltema , M. W. G. Johnson , M. D. Johnson , E. Krause , K. Kuehn , S. Kuhlmann , N. Kuropatkin , T. S. Li , M. Lima , J. L. Marshall , P. Melchior , F. Menanteau , R. C. Nichol , B. Nord , A. A. Plazas , K. Reil , E. S. Rykoff , M. Sako , E. Sanchez , V. Scarpine , M. Schubnell , E. Sheldon , M. Smith , R. C. Smith , M. Soares-Santos , F. Sobreira , E. Suchyta , M. E. C. Swanson , G. Tarle , D. Thomas , B. E. Tucker , D. L. Tucker , V. Vikram , A. R. Walker , J. Weller , W. Wester , R. C. Wolf

The effective redshift distribution $n(z)$ of galaxies is a critical component in the study of weak gravitational lensing. Here, we introduce a new method for determining $n(z)$ for weak lensing surveys based on high-quality redshifts and…

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…

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

As a consequence of galaxy clustering, close galaxies observed on the plane of the sky should be spatially correlated with a probability that is inversely proportional to their angular separation. In principle, this information can be used…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-19 F. Tosone , M. S. Cagliari , L. Guzzo , B. R. Granett , A. Crespi

We measure photometric redshifts and spectral types for galaxies in the COSMOS survey. We use template fitting technique combined with luminosity function priors and with the option to simultaneously estimate dust extinction (i.e. E(B-V))…

We present a catalogue of galaxy photometric redshifts and k-corrections for the Sloan Digital Sky Survey Seven Data Release (SDSS-DR7), available on the World Wide Web. The photometric redshifts were estimated with an artificial neural…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Ana Laura O'Mill , Fernanda Duplancic , Diego García Lambas , Laerte Sodré

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

We want to derive bias free, accurate photometric redshifts for those fields of the CFHTLS-Wide data which are covered in the u*, g', r', i' and z' filters and are public on January 2008. These are 37 square degrees in the W1, W3 and W4…

Astrophysics · Physics 2008-11-21 Fabrice Brimioulle , Michael Lerchster , Stella Seitz , Ralf Bender , Jan Snigula

Many of the cosmological tests to be performed by planned dark energy experiments will require extremely well-characterized photometric redshift measurements. Current estimates are that the true mean redshift of the objects in each photo-z…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-22 Daniel J. Matthews , Jeffrey A. Newman
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