Photometric Corrections


  • Eli Rykoff (SLAC) [erykoff (at)]
  • Nicolas Regnault (LPNHE) [nicolas.regnault (at)]

The Photometric Corrections (PC) working group helps fill in the gaps between the responsibilities of the LSST project and the needs of the DESC for calibrations.  Examples include the mitigation of Galactic extinction, which is crucial for all DESC science but explicitly is not part of LSST Data Management’s mandate, as well as more general work on photometric calibration systematics, which affect SN studies of Dark Energy directly and other probes via their impact on photometric redshifts. Photometric correction uncertainties are an essential cross-cutting technical issue that impacts all aspects of DESC science.

The primary goal of efforts in this working group will be to work with the LSST project team as well as the Sensor Anomalies WG to minimize and quantify systematic errors due to photometric calibration residuals arising from imperfect knowledge of instrumental throughput, atmospheric transmission, and Galactic extinction.  In addition, we will ensure clear documentation is maintained on how to map from calibrated magnitudes reported from LSST Level-2 analysis to physical fluxes, as well as independently evaluate calibration systematics and make them available to DESC working groups in a synthetic and practical form.  We will also coordinate forecasts for the LSST DM calibration strategies envisioned.  Finally, we emphasize that over the time period covered by this SRM there are many lessons to be learned from CFHT, DES, Pan-STARRS, and other pre-LSST surveys.