This PhD thesis deals with the realization of two original software tools for the Euclid Space Mission: 1. an End-to-End Mission Performance Simulator (E2ES) 2. a code to improve the wavelength calibration of the Euclid NISP spectroscopic data. Euclid is a mission selected by the European Space Agency (ESA) at the end of 2011 to understand the nature of the dark Universe. Starting from 2022, Euclid will investigate the distance-redshift relationship and the evolution of cosmic structures by means of two instruments: the Visual Imager (VIS) and the Near-Infrared Spectrometer and Photometer (NISP). The NISP instrument is designed to carry out slitless spectroscopy (for galaxy clustering probe) and imaging photometry (to detect weak lensing effects) in the near-infrared (NIR) wavelength. The design of a space mission is a long and complex process. The support of dedicated software tools is necessary, especially for the performance analysis of the mission itself. The request is then for specific tools that can simulate the complete behavior of the probe, its payload (i.e. those elements of the spacecraft specifically dedicated to producing mission data), and scientific data acquisition starting from synthetic scenes. A mission performance simulator (E2ES) with reduced simulation capabilities (called "Proto E2ES") has been implemented using the Python programming language in the framework of the European Space Agency (ESA) contract IPL-PTE/GLC/al/241.2014. My research job focused on the verification and validation of the simulator. In accordance to actual ESA software standardization, I developed a verification and validation process (contained in the "Euclid E2ES Verification and Validation Plan") to check the consistency and meaningfulness of output data resulting from the entire simulation chain; to check that the simulation output products are within the identified figure of merit; to determine whether or not the simulator software complies with the scientific requirements established in the baseline requirements document, and to define the test cases for the verification. A simulation on the entire input test catalog has been performed and all test cases foreseen by the plan completed with success. Exploiting the experience matured on the validation of the Euclid proto-E2ES, a collaboration started with INAF-IASF Milano to assess if the wavelength calibration accuracy of the NISP spectroscopic data can be validated using spectra of bright stars. Using stellar spectra of the NASA InfraRed Telescope Facility (IRTF), a deformation is applied to the spectra itself in order to reproduce the non-ideal nature of the NISP instrument. Also reference stellar spectra ("templates")are deformed, and the best match between the observed deformed spectrum and template is obtained through the evaluation of a merit function, the correlation function. The correlation has then been computed for all stellar spectra of the input catalog and templates. The scatter of the cross-correlation peak position for the different magnitude bins has been plotted against the magnitude itself. Results show that NISP spectra location validation can be successfully performed using stellar spectra for stars up to J-band magnitude equal to 17.0. Furthermore, the spatially varying wavelength solution across the field-of-view is accurate to a level of 0.4 pixels for stellar spectra up to J-band magnitude = 15.5.

The Euclid Space Mission: development of end-to-end simulator software tools aimed at improving the wavelength calibration of NISP instrument spectroscopic data / Battaglia, PAOLA MARIA. - (2018 Feb 02).

The Euclid Space Mission: development of end-to-end simulator software tools aimed at improving the wavelength calibration of NISP instrument spectroscopic data

BATTAGLIA, PAOLA MARIA
2018-02-02

Abstract

This PhD thesis deals with the realization of two original software tools for the Euclid Space Mission: 1. an End-to-End Mission Performance Simulator (E2ES) 2. a code to improve the wavelength calibration of the Euclid NISP spectroscopic data. Euclid is a mission selected by the European Space Agency (ESA) at the end of 2011 to understand the nature of the dark Universe. Starting from 2022, Euclid will investigate the distance-redshift relationship and the evolution of cosmic structures by means of two instruments: the Visual Imager (VIS) and the Near-Infrared Spectrometer and Photometer (NISP). The NISP instrument is designed to carry out slitless spectroscopy (for galaxy clustering probe) and imaging photometry (to detect weak lensing effects) in the near-infrared (NIR) wavelength. The design of a space mission is a long and complex process. The support of dedicated software tools is necessary, especially for the performance analysis of the mission itself. The request is then for specific tools that can simulate the complete behavior of the probe, its payload (i.e. those elements of the spacecraft specifically dedicated to producing mission data), and scientific data acquisition starting from synthetic scenes. A mission performance simulator (E2ES) with reduced simulation capabilities (called "Proto E2ES") has been implemented using the Python programming language in the framework of the European Space Agency (ESA) contract IPL-PTE/GLC/al/241.2014. My research job focused on the verification and validation of the simulator. In accordance to actual ESA software standardization, I developed a verification and validation process (contained in the "Euclid E2ES Verification and Validation Plan") to check the consistency and meaningfulness of output data resulting from the entire simulation chain; to check that the simulation output products are within the identified figure of merit; to determine whether or not the simulator software complies with the scientific requirements established in the baseline requirements document, and to define the test cases for the verification. A simulation on the entire input test catalog has been performed and all test cases foreseen by the plan completed with success. Exploiting the experience matured on the validation of the Euclid proto-E2ES, a collaboration started with INAF-IASF Milano to assess if the wavelength calibration accuracy of the NISP spectroscopic data can be validated using spectra of bright stars. Using stellar spectra of the NASA InfraRed Telescope Facility (IRTF), a deformation is applied to the spectra itself in order to reproduce the non-ideal nature of the NISP instrument. Also reference stellar spectra ("templates")are deformed, and the best match between the observed deformed spectrum and template is obtained through the evaluation of a merit function, the correlation function. The correlation has then been computed for all stellar spectra of the input catalog and templates. The scatter of the cross-correlation peak position for the different magnitude bins has been plotted against the magnitude itself. Results show that NISP spectra location validation can be successfully performed using stellar spectra for stars up to J-band magnitude equal to 17.0. Furthermore, the spatially varying wavelength solution across the field-of-view is accurate to a level of 0.4 pixels for stellar spectra up to J-band magnitude = 15.5.
2-feb-2018
GREGORIO, ANNA
30
2016/2017
Settore FIS/01 - Fisica Sperimentale
Università degli Studi di Trieste
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2917553
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