Spectral modeling of type Ia supernovae, observed by the Nearby Supernova Factory, in order to improve extragalactic distance measurement
Description
At the end of the 90's, two independent teams showed, based on distance measurements of type Ia supernovae (SNIa), that expansion of our Universe is accelerating. Since then, one of the priorities of modern cosmology is to characterize this phenomenon and to understand its nature. The improvement of distance measurements of SNIa is one technique to improve the constraints on acceleration and to determine the physical nature of it. This document develops a new SNIa spectral energy distribution model, called the Supernova Useful Generator and Reconstructor (SUGAR), which improves distance measurement. This model is constructed from SNIa spectral properties and spectrophotometric data from The Nearby Supernova Factory collaboration. The main advancement proposed in SUGAR is the addition of two additional parameters to characterize the SNIa variability. The first depends on the properties of SNIa ejecta velocity, the second depends on their calcium lines. The addition of these parameters as well as the high quality of the data of The Nearby Supernova Factory collaboration make SUGAR the best model available to describe the spectral energy distribution of SNIa and improves distances measurements of the order of 15 % relative to the usual method. The performance of this model makes it an excellent candidate for preparing future experiments like LSST or WFIRST. In addition, this document presents an analysis of the effect of SNIa belonging to a galaxy cluster on its distance measurement. Galaxies of a cluster have a peculiar velocity much higher than the assumed value when measuring distances with SNIa. This has the effect of introducing a systematic error into the distance measurement. Failure to take into account this effect may degrade the distance measurement by 2.5% for SNIa belonging to a cluster. This analysis was carried out using data from the collaboration of the Nearby Supernova Factory and public catalogs of galaxy cluster. (author)
Abstract (French)
A la fin des annees 90, deux equipes independantes ont montre l'expansion acceleree de notre Univers, a partir des mesures de distances de supernovas de type Ia (SNIa). Depuis, une des priorites de la cosmologie moderne est de caracteriser ce phenomene et d'en comprendre ses fondements. L'amelioration des mesures de distance realisees a partir des SNIa est une technique majeure permettant de mieux caracteriser l'acceleration et donc de determiner la nature physique de ce phenomene. Ce document developpe un nouveau modele de distribution spectrale en energie de SNIa nomme le Supernova Useful Generator And Reconstructor (SUGAR) permettant d'ameliorer les mesures des distances. Ce modele est construit a partir des proprietes spectrales des SNIa et des donnees spectrophotometriques de la collaboration The Nearby Supernova Factory. L'avancee principale, proposee dans SUGAR, reside dans l'ajout de deux parametres supplementaires pour caracteriser la variabilite des SNIa. Le premier depend des proprietes des vitesses des ejectas des SNIa, le deuxieme depend de leurs raies du calcium. L'ajout de ces parametres, ainsi que la grande qualite des donnees de la collaboration the Nearby Supernova Factory font de SUGAR le meilleur modele qui existe pour decrire la distribution spectrale en energie des SNIa et ameliore les mesures des distances de l'ordre de 15% par rapport a la methode usuelle. Les performances de ce modele en font un excellent candidat pour preparer les experiences futures comme LSST ou WFIRST. Par ailleurs, ce document presente une analyse sur l'effet de l'appartenance d'une SNIa a un amas de galaxies sur sa mesure de distance. Les galaxies d'un amas possedent une vitesse propre largement superieure a la valeur supposee lors de la mesure des distances avec les SNIa. Ceci a pour consequence d'introduire une source d'erreur systematique sur la mesure de distance. Le fait de ne pas prendre en compte cet effet peut degrader la mesure de distance de l'ordre de 2,5% pour les SNIa appartenant a un amas. Cette analyse a ete realisee en utilisant les donnees de la collaboration the Nearby Supernova Factory et des catalogues public d'amas de galaxies. (auteur)
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Additional details
Additional titles
- Original title (French)
- Modelisation des spectres des Supernovas de Type Ia observes par la collaboration The Nearby Supernova Factory dans le but d'ameliorer les mesures de distances extragalactiques
Publishing Information
- Imprint Pagination
- 247 p.
- Report number
- FRNC-TH--11181
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 51109444
- Subject category
- S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- CLASSIFICATION; COSMOLOGY; DISTANCE; ENERGY SPECTRA; GALAXY CLUSTERS; GAUSSIAN PROCESSES; HUBBLE EFFECT; INFLATIONARY UNIVERSE; LUMINOSITY; SPECTROPHOTOMETRY; TYPE I SUPERNOVAE
- Descriptors DEC
- BINARY STARS; COSMOLOGICAL MODELS; ERUPTIVE VARIABLE STARS; MATHEMATICAL MODELS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; SPECTRA; STARS; SUPERNOVAE; VARIABLE STARS
Optional Information
- Notes
- 185 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses