Introducing the data-reduction pipeline for the Nordic Optical Telescope Transient Explorer spectrograph

Abstract

The Nordic Optical Telescope Transient Explorer (NTE) is a new multiarm imaging and spectroscopic instrument being developed for the Nordic Optical Telescope (NOT). In spectroscopic mode, NTE provides simultaneous wavelength coverage from 320nm to 2440nm through three independent arms. To support the time-critical science goals of NTE, a robust and highly automated data reduction system is required, capable of delivering both quick-look products for real-time observing decisions and fully calibrated science data. We present the current status of the NTE spectrograph data reduction pipeline and its validation using simulated instrument data. The pipeline is built upon the PypeIt spectroscopic reduction framework. We describe the development of simulated datasets used to test the reduction workflow prior to first light, including wavelength calibration, object extraction, flux calibration, and co-addition across echelle orders and spectrograph arms. We demonstrate successful end-to-end reductions of simulated observations spanning the full wavelength range of the instrument. In addition, we describe our approach to fully automating PypeIt and integrating it into the observatory software architecture, using currently operational instrument ALFOSC as a testbed. We also present an algorithm for echelle order rectification and stitching that is not native to the PypeIt framework. These developments establish the foundation for both real-time and archival processing of NTE data and provide a framework for continued pipeline development ahead of instrument commissioning.