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Analyse des 5 ans de données de l'expérience SuperNova Legacy Survey

Abstract : The Supernova Legacy Survey (SNLS) is a program that aims at discovering and photometrically following hundreds of Type Ia supernovæ (SNe Ia). Its goal is to measure the expansion history of the Universe in order to constrain the nature of the dark energy, namely its equation of state wDE. The survey completed its data taking during summer 2008 after 5 years of program. This PhD work consists in the analysis of these 5 years of SNLS data and the photometry of the 419 Type Ia supernovæ discovered and spectroscopically identified. For each supernova, the lightcurves are produced in the gMrMiMzM bands, calibrated and fitted with a spectrophotometric model. A new photometric method which does not make use of any pixel resampling has also been implemented and tested. This method preserves the pixels statistical properties, and produces this way more accurate flux measurement statistical uncertainties, that can be propagated to cosmological measurements. Both photometry results were checked and compared using calibration stars and supernovae, proving that the accuracy of the new method flux measurement uncertainty is indeed better, and that the photometric accuracy and stability of both techniques are similar. A sample of supernovæ with unprecedented statitics and quality is now available for cosmological analysis. With the complement of an external nearby supernovæ sample, a measurement within 5% of the dark energy equation of state of dark energy is thus for the first time within reach.
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Contributor : Nicolas Fourmanoit <>
Submitted on : Wednesday, April 20, 2011 - 2:20:28 PM
Last modification on : Monday, October 19, 2020 - 11:10:47 AM
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  • HAL Id : tel-00587450, version 1


N. Fourmanoit. Analyse des 5 ans de données de l'expérience SuperNova Legacy Survey. Cosmologie et astrophysique extra-galactique [astro-ph.CO]. Université Pierre et Marie Curie - Paris VI, 2010. Français. ⟨tel-00587450⟩



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