# Recherche et étude de supernovae : mesure du taux d'explosion

Abstract : As the last stage of stellar evolution, supernovae are a fundamental tool to probe the evolution of galaxies. They are the main mecanism to release intermediate mass elements (like oxygen from gravitational supernovae --- type II/Ib/Ic) and iron peak elements (from thermonuclear supernovae also known as type Ia) in the interstellar medium. In this picture, the explosion rate, which is the number of events per unit of time and per unit of volume or per unit of galactic luminosity, is a very interesting quantity to understand chemical evolution of galaxies.
From a decade, supernova searches have taken a new turn with CCD cameras which allow to get homogeneous and bias-controled supernova samples. The search itself is done by subtracting images taken one month apart. It's in this framework that EROS experiment, which uses a 1 meter telescope in Chile with 2 wide field CCD cameras, dedicated about 15 \% of its time during 4 years to nearby supernova search. The work presented here has been done after two observation campaigns by EROS, in 1999 and 2000, within international collaborations in order to get sufficient telescope time to follow up the events discovered. Fifteen type Ia supernovae were discovered by EROS.
The measurement of the detection efficiency, using a Monte-Carlo simulation, allows to get the type Ia supernova explosion rate at a redshift around 0.13. The result is $0.23^(+0.09+0.07)_(-0.05-0.07)\ h^2$ SNu where 1 SNu = 1 SN / $10^(10)\ \text(L)_(\odot)^B$ / century. This value in compatible with the previous EROS such measurement, done with a much smaller sample, at this redshift. We can compare our result with the one got by the \textit(Supernova Cosmology Project) at a redshift of 0.55, which is $0.58^(+0.10\ +0.10)_(-0.09\ -0.09)\ h^2$ SNu. The difference between both values implies a quite large evolution between these two periods in the history of the universe.
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https://tel.archives-ouvertes.fr/tel-00002331
Contributor : Guillaume Blanc <>
Submitted on : Thursday, December 23, 2004 - 12:49:23 PM
Last modification on : Thursday, November 12, 2020 - 11:08:02 AM
Long-term archiving on: : Monday, September 20, 2010 - 11:59:41 AM

### Identifiers

• HAL Id : tel-00002331, version 2

### Citation

Guillaume Blanc. Recherche et étude de supernovae : mesure du taux d'explosion. Astrophysique [astro-ph]. Université Paris Sud - Paris XI, 2002. Français. ⟨tel-00002331v2⟩

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