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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 redshift such that the difference between the estimate and the spectroscopic redshift is small. Our methodology results(More)
The main challenge today in photometric redshift estimation is not in the accuracy but in understanding the uncertainties. We introduce an empirical method based on Random Forests to address these issues. The training algorithm builds a set of optimal decision trees on subsets of the available spectroscopic sample, which provide independent constraints on(More)
We propose to describe the variety of galaxies from the Sloan Digital Sky Survey (SDSS) by using only one affine parameter. To this aim, we construct the Principal Curve (P-curve) passing through the spine of the data point cloud, considering the eigenspace derived from Principal Component Analysis (PCA) of morphological, physical and photometric galaxy(More)
We analyze the clustering properties of ultraviolet selected galaxies by using GALEX-SDSS data at z < 0.6 and CFHTLS deep u ′ imaging at z ∼ 1. These datasets provide a unique basis at z ≤ 1 which can be directly compared with high redshift samples built with similar selection criteria. We discuss the dependence of the correlation function parameters (r 0 ,(More)
With the goal of constructing Star-Formation Rates (SFR) from AKARI Infrared Camera (IRC) data, we analyzed an IR-selected GALEX-SDSS-2MASS-AKARI(IRC & Far-Infrared Surveyor) sample of 153 nearby galaxies. The far-infrared fluxes were obtained from AKARI diffuse maps to correct the underestimation for extended sources raised by PSF pho-tometry. SFRs of(More)
We present the first results obtained from the identification of ∼ 30 000 sources in the Spitzer/24 µm observations of the COSMOS field at S 24µm > ∼ 80 µJy. Using accurate photometric redshifts (σ z ∼ 0.12 at z ∼ 2 for 24 µm sources with i + < ∼ 25 mag AB) and simple extrapolations of the number counts at faint fluxes we resolve with unprecedented detail(More)
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