Image Slicer Performances from a Demonstrator for the SNAP/JDEM Mission - Part I: Wavelength Accuracy

TL;DR

This paper evaluates the wavelength measurement accuracy of an integral field spectrograph with an image slicer designed for the SNAP/JDEM mission, demonstrating improved spectral precision by eliminating slit effects.

Contribution

It presents the first validation of an image slicer-based spectrograph's wavelength accuracy, showcasing its enhanced spectral measurement performance for space-based supernova observations.

Findings

The demonstrator achieves high spectral measurement accuracy in visible and near-infrared.

The image slicer improves spectral precision by removing slit effects.

Validation of the optical design through prototyping and testing.

Abstract

A well-adapted visible and infrared spectrograph has been developed for the SNAP (SuperNova/Acceleration Probe) experiment proposed for JDEM. The instrument should have a high sensitivity to see faint supernovae but also a good redshift determination better than 0.003(1+z) and a precise spectrophotometry (2%). An instrument based on an integral field method with the powerful concept of imager slicing has been designed. A large prototyping effort has been performed in France which validates the concept. In particular a demonstrator reproducing the full optical configuration has been built and tested to prove the optical performances both in the visible and in the near infrared range. This paper is the first of two papers. The present paper focus on the wavelength measurement while the second one will present the spectrophotometric performances. We adress here the spectral accuracy expected both in the visible and in the near infrared range in such configuration and we demonstrate, in particular, that the image slicer enhances the instrumental performances in the spectral measurement precision by removing the slit effect. This work is supported in France by CNRS/INSU/IN2P3 and by the French spatial agency (CNES) and in US by the University of California.