Poster Abstract

P11.5 Koshy George (Ludwig-Maximilians-University)

Theme: Other

Calibration of ground based survey data using Gaia: Application to DES

The calibration of ground based optical imaging data to photometric accuracy of 10 mmag over the full survey and to color uniformity better than 5 mmag on the scale of the VIS focal plane is a key science requirement for the Euclid mission. These accuracies enable stable photometric redshifts of galaxies and modeling of the color
dependent VIS PSF for weak lensing studies. We use the Gaia photometry to calibrate the griz magnitudes of Dark Energy Survey (DES) data to meet the stringent requirements from Euclid. The Gaia G band magnitude along with the BP-RP color information of stars observed in the DES single epoch exposures are used to derive the transformation from Gaia to DES photometry for individual CCDs and to characterize persistent photometric errors across the DES focal plane. We also use Gaia photometry to study the bandpass variations across the DECam focal plane in the griz bandpasses. The details of the calibration and the methodology will be presented.