# Photométrie différentielle de supernovae de type Ia lointaines (0.5

Abstract : After an introduction of the general context of the standard'' cosmology, this thesis presents, how, using comparison of the apparent luminosity of nearby and distant type Ia supernovae (SNIa), it is possible to specify the geometry of the universe and perform a measurement of the principal cosmological parameters. We describe, after, how, from observations using the wide field camera CFH12K mounted on the CFHT (Canada France Hawaii Telescope, 3.6m, Hawaii) and softwares developed within our group, we were able to discover during the spring 2001 a batch of 4 distant SNIa. A similar search carried out with the CTIO (Cerro Tololo Interamerican Telescope, 4M, Chile) by our collaborators allowed the discovery of about ten additional supernovae. We present in this thesis the analyze of the 6 farthest supernovae (with redshift between 0.5 and 1.2) that were followed by the instrument WFPC2 of the Hubble Space Telescope. From these observations, we constructed their lightcurves using photometric differential analysis specific to the instrument WFPC2 that we developed during this work. The simulation of the flux of those supernovae within the observationnal instruments enabled us to construct lightcurve models and then fits of their characteristics: apparent luminosity at the time of maximum and decline rate. Finally, using the comparison of this batch to a batch of about one hundred nearby SNIa coming from the literature, we performed a measure of the cosmological parameters. We find, considering a flat universe, a reduced density of matter of 0.35 (0.15 stat) and 0.22 (0.25 stat) respectively for the supernovae with a redshift around 0.5 and around 1.
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https://tel.archives-ouvertes.fr/tel-00003726
Contributor : Julien Raux <>
Submitted on : Thursday, November 6, 2003 - 4:19:48 PM
Last modification on : Friday, April 10, 2020 - 5:29:21 PM
Long-term archiving on: : Wednesday, September 12, 2012 - 11:25:10 AM

### Identifiers

• HAL Id : tel-00003726, version 1

### Citation

Julien Raux. Photométrie différentielle de supernovae de type Ia lointaines (0.5. Cosmologie et astrophysique extra-galactique [astro-ph.CO]. Université Paris Sud - Paris XI, 2003. Français. ⟨tel-00003726⟩

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