Cosmology Seminar- Towards Supernovae Cosmology with the Zwicky Transient Facility

The accelerated expansion of the Universe was first observed almost 30 years ago using Type 1a supernovae (SN1a) as distance indicators. Since then, the Hubble-Lemaître diagram has been populated by many experiments, and modern analyses use approximately 2000 SN1a. Together with measurements of the Baryon Acoustic Oscillations and the Cosmic Microwave Background, they now hint for an evolving dark energy.
These different compilations use a common set of low-redshift supernovae from various instruments with their own calibrations and completeness. The Zwicky Transient Facility (ZTF) will change this landscape by providing, for the first time, a uniform set of nearby supernovae over the whole northern sky.
In this talk I will introduce ZTF and its newest SN data release (DR2) which includes more than 2000 nearby SN1a, well-sampled, and spectroscopically classified between March 2018 and December 2020.
I will then show our progress in photometric calibration to enable cosmological analyses. I will focus mostly on the so called relative « ubercalibration » to improve survey uniformity.