Photometry Calibration of the SNLS Fields
Nicolas Regnault, Pierre Astier, Jean-Charles Cuillandre, Kyan Schahmaneche

Abstract: We present the photometric calibration of the 3.5 year SNLS dataset. We, will first focus on the internal calibration of the Megacam imager. In, particular, the uniformity of the focal plane photometric response has, been mapped with great care. This is essential, since only a subset of the, 36 CCDs can be directly calibrated using standard star observations. The, uniformity of the imager passbands was also studied, and evidence for, non-uniformities were found. We will then describe how we transfer the, stellar calibration we obtain to the SNe~Ia, whose SEDs differ, significantly from that of stars. Finally, we will present the SNDice, project, which will deliver a instrumental calibration of Megacam using, direct illumination of the primary mirror with calibrated LEDs.