Impact Of Noise Covariance And Nonlinearities In Nir H2rg Detectors

We characterize at pixel level a NIR H2RG detector read with SIDECAR ASIC, similar to the detectors used in Euclid's Near IR Spectrometer Photometer (NISP). We derive the full covariance matrix formulae, extending the results from previous publications, and compare them to data and simulations for NISP baseline operating modes. The nonlinear response of the detector is measured and high precision maps are derived for in-flight or on-ground correction. High precision maps of the conversion gain are also determined using the Photon Transfer Curve technique.