Topic
Photometric redshift
About: Photometric redshift is a research topic. Over the lifetime, 1849 publications have been published within this topic receiving 95401 citations.
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TL;DR: In this article, photometric redshifts for an uniquely large and deep sample of 522286 objects with AB < 25 in the Canada-France Legacy Survey ''Deep Survey'' fields were presented.
Abstract: We present photometric redshifts for an uniquely large and deep sample of 522286 objects with i'_{AB}<25 in the Canada-France Legacy Survey ``Deep Survey'' fields, which cover a total effective area of 3.2 deg^2. We use 3241 spectroscopic redshifts with 0
1,567 citations
TL;DR: A redshift quality parameter, -->Qz, is introduced, which provides a robust estimate of the reliability of the photometric redshift estimate, and is provided for the FIRES, MUSYC, and FIREWORKS surveys.
Abstract: We describe a new program for determining photometric redshifts, dubbed EAZY. The program is optimized for cases where spectroscopic redshifts are not available, or are only available for a biased subset of the galaxies. The code combines features from various existing codes: it can fit linear combinations of templates, it includes optional flux- and redshift-based priors, and its user interface is modeled on the popular HYPERZ code. A novel feature is that the default template set, as well as the default functional forms of the priors, are not based on (usually highly biased) spectroscopic samples, but on semianalytical models. Furthermore, template mismatch is addressed by a novel rest-frame template error function. This function gives different wavelength regions different weights, and ensures that the formal redshift uncertainties are realistic. We introduce a redshift quality parameter, -->Qz, which provides a robust estimate of the reliability of the photometric redshift estimate. Despite the fact that EAZY is not trained on spectroscopic samples, the code (with default parameters) performs very well on existing public data sets. For K-selected samples in CDF-South and other deep fields, we find a 1 ? scatter in -->? z/(1 + z) of 0.034, and we provide updated photometric redshift catalogs for the FIRES, MUSYC, and FIREWORKS surveys.
1,454 citations
TL;DR: In this article, photometric redshifts for an uniquely large and deep sample of 522286 objects with i'_{AB}<25 in the Canada-France Legacy Survey ''Deep Survey'' fields, which cover a total effective area of 3.2 deg^2, are presented.
Abstract: We present photometric redshifts for an uniquely large and deep sample of 522286 objects with i'_{AB}<25 in the Canada-France Legacy Survey ``Deep Survey'' fields, which cover a total effective area of 3.2 deg^2. We use 3241 spectroscopic redshifts with 0
1,398 citations
TL;DR: In this article, ultraviolet observations of nearby galaxies with the ANS were used to derive ultraviolet spectra for different galaxy types, and these spectra were used with existing visible spectrophotometry to calculate K-corrections, and to predict colors and magnitudes for various galaxy types as a function of redshifts, to z = 2.
Abstract: Ultraviolet observations of nearby galaxies with the ANS are used to derive ultraviolet spectra for different galaxy types. These spectra are used with existing visible spectrophotometry to calculate K-corrections, and to predict colors and magnitudes for various galaxy types as a function of redshifts, to z = 2. No evolutionary effects are considered. It appears that the first-ranked cluster galaxies on blue emulsions should be spirals for z greater than or approximately equal to 0.5.
1,301 citations
University of Hawaii1, California Institute of Technology2, Max Planck Society3, Centre national de la recherche scientifique4, Institut d'Astrophysique de Paris5, University of California, Riverside6, Ehime University7, Tohoku University8, University of Arizona9, ETH Zurich10, ASTRON11, INAF12, University of Padua13, Columbia University14, European Southern Observatory15
TL;DR: In this article, a chi2 template-fitting method was used and calibrated with large spectroscopic samples from VLT-VIMOS and Keck-DEIMOS.
Abstract: We present accurate photometric redshifts in the 2-deg2 COSMOS field. The redshifts are computed with 30 broad, intermediate, and narrow bands covering the UV (GALEX), Visible-NIR (Subaru, CFHT, UKIRT and NOAO) and mid-IR (Spitzer/IRAC). A chi2 template-fitting method (Le Phare) was used and calibrated with large spectroscopic samples from VLT-VIMOS and Keck-DEIMOS. We develop and implement a new method which accounts for the contributions from emission lines (OII, Hbeta, Halpha and Ly) to the spectral energy distributions (SEDs). The treatment of emission lines improves the photo-z accuracy by a factor of 2.5. Comparison of the derived photo-z with 4148 spectroscopic redshifts (i.e. Delta z = zs - zp) indicates a dispersion of sigma_{Delta z/(1+zs)}=0.007 at i<22.5, a factor of 2-6 times more accurate than earlier photo-z in the COSMOS, CFHTLS and COMBO-17 survey fields. At fainter magnitudes i<24 and z<1.25, the accuracy is sigma_{Delta z/(1+zs)}=0.012. The deep NIR and IRAC coverage enables the photo-z to be extended to z~2 albeit with a lower accuracy (sigma_{Delta z/(1+zs)}=0.06 at i~24). The redshift distribution of large magnitude-selected samples is derived and the median redshift is found to range from z=0.66 at 22
1,281 citations