An automated pipeline for Ultra-Violet Imaging Telescope

Ghosh, S. K.; Tandon, S. N.; Singh, S. K.; Shelat, D. S.; Tahlani, P.; Singh, A. K.; Srinivasan, T. P.; Joseph, P.; Devaraj, A.; George, K.; Mohan, R.; Postma, J. und Stalin, C. S. (2022): An automated pipeline for Ultra-Violet Imaging Telescope. In: Journal of Astrophysics and Astronomy, Bd. 43, Nr. 2, 77

Abstract

We describe a versatile pipeline for processing the data collected by the Ultra-Violet Imaging Telescope (UVIT) on board Indian multi-wavelength astronomical satellite ASTROSAT. The UVIT instrument carries out simultaneous astronomical imaging through selected filters/gratings in far-ultra-violet (FUV), near-ultra-violet and visible (VIS) bands of the targeted circular sky field (similar to 0.5 degrees dia). This pipeline converts the data (Level 1) emanating from UVIT in their raw primitive format supplemented by inputs from the spacecraft sub-systems into UV sky images (and slitless grating spectra) and associated products readily usable by astronomers (Level 2). The primary products include maps of Intensity (rate of photon arrival), error on Intensity and effective Exposure. The pipeline is open source, extensively user configurable with many selectable parameters and its execution is fully automated. The key ingredients of the pipeline include extraction of drift in the pointing of the spacecraft, and disturbances in pointing due to internal movements;application of various corrections to measured position in the detector for each photon - e.g., differential pointing with respect to a reference frame for shift and add operation, systematic effects and artefacts in the optics of the telescopes and detectors, exposure tracking on the sky, alignment of sky products from multi-episode exposures to generate a consolidated set and astrometry. Detailed logs of operations and intermediate products for every processing stage are accessible via user-selectable options. While large number of selectable parameters are available for the user, a well characterized 'standard default' set is used for executing this pipeline at the Payload Operation Centre (POC) for UVIT and selected products are archived and disseminated by the Indian Space Research Organization (ISRO) through its ISSDC portal.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0250-6335
• Sprache: Englisch