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Seminar: When more data is not enough: instrumental calibration challenges in next-generation cosmology by Thierry Souverin
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Europe/Paris
Auditorium Marcel Vivargent (LAPP)
Auditorium Marcel Vivargent
LAPP
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Description
Cosmology is entering a new era of precision, driven by upcoming wide-field surveys with increased sensitivity, improved image quality, and larger sample sizes. In type Ia supernova (SNe Ia) cosmology, high-cadence surveys such as the Legacy Survey of Space and Time (LSST) will substantially increase the number of observed events, significantly reducing statistical uncertainties on cosmological inferences.
Meanwhile, next-generation cosmic microwave background (CMB) experiments such as the Simons Observatory and LiteBIRD aim to measure polarization with unprecedented accuracy. These measurements could enable the detection of primordial B-mode polarization and cosmic birefringence, the former supporting inflation and the latter pointing toward extensions to ΛCDM.
In both fields, improved cadence and sensitivity reduce statistical uncertainties, leaving instrumental systematics as the dominant limitation. Therefore, more data alone is no longer sufficient; absolute calibration becomes critical. Milli-magnitude photometric precision is required for SNe Ia, while CMB experiments demand polarimetric calibration at the 0.01°–0.1° level.
In this seminar, I will present two calibration experiments: StarDICE for photometric calibration and POLOCALC for polarimetric calibration. Both aim to establish an absolute metrological chain from laboratory standards to astronomical observations, enabling accurate, survey-independent calibration of instrumental response.