Oldest Supernovae of the Universe
They are the dinosaurs of supernovae. Far from being extinct, they were very common in the early Universe. SNLS 06D4eu and SNLS 07D2bv, discovered between 2006 and 2007, are two super bright supernovae with a serious shortage of hydrogen. Much older than the Sun, they are 100 times brighter than a normal supernova. The study belongs of the Astrophysical Journal.
Pair of supernovae discovered between 2006 and 2007 is now considered two of the brightest objects ever sighted. It is a result obtained under the program Supernova Legacy Survey (SNLS) by a group of astronomers who spotted two supernovae at a distance of 10 billion light years from Earth and hundreds of times brighter than a normal supernova. The question facing scientists is how the two stellar explosions can emit as much light? The mechanism that leads to the explosion of a star (the collapse of a massive star into a black hole or a neutron star) cannot explain, in fact, this intense brightness.
At the time of the discovery, said Andrew Howell, the Observatory Global Telescope Network (LCOGT), “we did not know how to classify these objects and did not understand if they were in our galaxy or in a more distant one. I showed the results of observations during a conference and nobody have thought then that it was just two very distant supernovae and so bright. We thought it was impossible.”
SNLS – 06D4eu is the most distant and most likely the brightest of an entire class of similar objects called super bright supernovae. Specifically, the two objects discovered by this group of researchers are even more special and rare because they have no hydrogen. The other is called supernova SNLS 07D2bv.
From the study, it is shown that supernovae are probably fed by the creation of a magnetar, i.e. a neutron star that has a huge magnetic field and that runs hundreds of times per second. When a massive star collapses into a neutron star, its magnetic field grows in power. The magnetars have the mass of the Sun in size and have magnetic fields a hundred billion times that of the Earth. While some of these super-luminous supernovae have been seen since it was first announced their existence in 2009, and the creation of a magnetar years ago has been hypothesized as a possible source of energy, the results of the team led by Howell is the first to correlate the two phenomena, the explosion of a supernova and the birth of a magnetar.
Astronomers have arrived at their conclusions by using the models of supernovae. Daniel Kasen, Lawrence Berkeley National Lab, found that the star was initially much larger before losing its outer layers and then explode leaving a small bare nucleus. From that moment on, the “small” star began to rotate rapidly before finally dying. It is at this point that the core would have collapsed by created the magnetar: the energy generated by the speed would be transformed into huge magnetic energy.
Discoveries thanks to the combined work of the Canada -France -Hawaii Telescope, the Very Large Telescope (VLT) of the Keck and Gemini telescopes, it took years and years of observations to determine their exact location and the amount of energy they produce. Born when the universe was “only” 4 billion years, are much older than our Sun,” At the same moment there was another star who then died and where they were born gas clouds and the sun and the system solar,” added Howell. “Now the photons of these supernovae hit the Earth 10 billion years later.”