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Observations cosmologiques avec un télescope grand champ spatial: Simulations pixels du spectromètre sans fente d'EUCLID

Abstract : The observations of the supernovae, the cosmic microwave background, and more recently the measurement of baryon acoustic oscillations and the weak lensing effects, converge to a Lambda CDM model, with an accelerating expansion of the today Universe. This model need two dark components to fit the observations, the dark matter and the dark energy. Two approaches seem particularly promising to measure both geometry of the Universe and growth of dark matter structures, the analysis of the weak distortions of distant galaxies by gravitational lensing and the study of the baryon acoustic oscillations. Both methods required a very large sky surveys of several thousand square degrees. In the context of the spectroscopic survey of the space mission EUCLID, dedicated to the study of the dark side of the universe, I developed a pixel simulation tool for analyzing instrumental performances. The proposed method can be summarized in three steps. The first step is to simulate the observables, ie mainly the sources of the sky. I work up a new method, adapted for spectroscopic simulations, which allows to mock an existing survey of galaxies in ensuring that the distribution of the spectral properties of galaxies are representative of current observations, in particular the distribution of the emission lines. The second step is to simulate the instrument and produce images which are equivalent to the expected real images. Based on the pixel simulator of the HST, I developed a new tool to compute the images of the spectroscopic channel of EUCLID. The new simulator have the particularity to be able to simulate PSF with various energy distributions and detectors which have different pixels. The last step is the estimation of the performances of the instrument. Based on existing tools, I set up a pipeline of image processing and performances measurement. My main results were: 1) to validate the method by simulating an existing survey of galaxies, the WISP survey, 2) to determine the tolerances on the energy distribution of the PSF for the slitless spectrometer of EUCLID, 3) to determine the tolerances on the properties of near-infrared detectors of EUCLID.
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Contributor : Julien Zoubian <>
Submitted on : Sunday, October 14, 2012 - 3:50:32 PM
Last modification on : Tuesday, October 20, 2020 - 3:10:26 AM
Long-term archiving on: : Saturday, December 17, 2016 - 12:52:34 AM


  • HAL Id : tel-00741580, version 1



Julien Zoubian, Jean-Paul Kneib, Bruno Milliard. Observations cosmologiques avec un télescope grand champ spatial: Simulations pixels du spectromètre sans fente d'EUCLID. Cosmologie et astrophysique extra-galactique [astro-ph.CO]. Aix-Marseille Université, 2012. Français. ⟨tel-00741580⟩



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