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The TAROT telescope recorded the explosion of a star located at 13.4 billion of light years

Thursday, June 6, 2013 at 9:04 p.m. the U.S. Swift satellite detected a gamma ray burst that lasted nearly five minutes. The satellite sent the position of the gamma-ray burst to the dedicated NASA center which distributed the position to point telescopes placed in ground-based observatories. Among them, telescopes of CADOR network observed the gamma-ray burst called GRB 130606A.
Astronomers of IRAP are involved in the operation of the CADOR network. The network includes three telescopes: TAROT Calern in France (Observatoire de la Côte d'Azur),TAROT La Silla in Chile (European Southern Observatory) and Zadko located in Australia (University of Western Australia). It was the night over TAROT Calern when the burst occurred. The telescope began observations seven minutes after the start of the burst. The first images of TAROT show a new star whose brightness decreases rapidly.

grb130606a_2

Figure above : Sequence of images taken by telescopes TAROT and Zadko. The optical emission of the gamma-ray burst GRB 130606A is visible as a star (at the intersection of lines on the left image). The brightness of the star decreases rapidly within hours to be no longer detectable in the right image.

One hour and thirty minutes after the start of GRB the Spanish astronomers pointed the giant telescope Gran Tecan located in the Canary Islands and they obtained the spectrum of the new star. The spectrum analysis has soon revealed that the star shows a redshift of 5.913. Considering the model of the universe proposed by the results of the Planck mission, we deduce that the gamma-ray burst occurred when the universe was only a billion years old. This early stage of the evolution of the Universe is almost unknown and the sporadic presence of a brilliant object such a gamma-ray burst acts as a lighthouse that illuminates for a few hours the 13.4 billion light years that separate us to it. The information gathered by the telescopes that have observed GRB 130606A are now finely analyzed by cosmologists.

Theories associate the phenomenon of gamma burst GRB 130606A with the explosion of a high mass star (several tens of times the mass of the Sun). The gamma-ray burst theory predicts the formation of a black hole from the original star. The TAROT images show the creation of a black hole that was formed 13.4 billion years ago.

GRB 130606A is one of the brightest astrophysical objects in the Universe. For comparison TAROT observed it four times brighter than the brightest of all known quasars. The number of such gamma-ray bursts can be counted on the fingers of one hand! Many mysteries remain to be clarified including why the most distant gamma-ray bursts can be so powerful.
Telescopes TAROT of the CADOR network were designed in IRAP with the help of funds from CNRS. They were commissioned in 1998 (Calern) and 2006 (La Silla). TAROT telescopes have observed more than 120 gamma-ray bursts that gave16 publications. Other programs also conducts observations with the telescopes of the CADOR network (supernovae, pulsating stars, asteroids). For further details, consult the paper on TAROT Messenger published in the journal edited by the European Southern Observatory:

Article : "Six Years of Science with the TAROT Telescope at La Silla" by Alain Klotz, Michel Boer, Jean-Luc Atteia, Bruce Gendre, Jean-François Le Borgne, Eric Frappa, Frederic Vachier, Jerome Berthier, http://www.eso.org/sci/publications/messenger/archive/no.151-mar13/messenger-no151-6-9.pdf

Contact IRAP : Alain KLOTZ, alain.klotz@irap.omp.eu

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