Press Release
PRESS RELEASE
Monica Sperandio:
Prof. Chincarini, the Swift satellite detected a gamma ray burst that following optical observations by your group resulted to be the most distant cosmic object ever observed, located at a distance of about 13 billion light years at a time when the Universe was only 630 million years old. What is this unique detection telling us:
Guido Chincarini:
We are discovering that GRBs, and their progenitors, exist in these early epoch of the Universe and that the formation of metals was already in place. This is an observational milestone and we need to insist on this line to get even more detailed data to measure the characteristics of stars, galaxies and IGM at a time when the Universe was very young. Amazingly, as shown by the X ray analysis done by Margutti, the X-ray light curve does not differ from those observed at lower redshift.
As Galileo Galilei taught us 400 years ago we need to understand the language of Nature and transform our readings in theory and models. But let me add that this observation is a very good example of how communication and coordination works: Internationally the results were build up step by step by various groups and within our group it was a real team work coordinated by the Swift group with the collaboration of the Telescopio Nazionale Galileo (TNG). Be always ready and get there as soon as possible.
Monica Sperandio:
Yes, I understand that at that distance the spectrum is all shifted toward the near infrared and that special instrumentation and fast reaction is required to beat the rapid fading of these objects. You mentioned metals: Dr. Della Valle could they form that early and how?
Massimo DellaValle:
During the Big Bang only the lightest elements were formed mostly hydrogen and helium. Lithium and Beryllium were only made in trace quantities. The other 90 elements found on the Earth were created through nuclear reactions occurring in the stellar interiors and spread over in the space through huge stellar explosions that we call Supernovae. The Gamma-ray Burst that we have observed, originated in one of this event. By observing at such distant objects we will be able to track early star formation and witness the formation of the heavy elements. The observation may finally guide the refinement of the theoretical models.
Monica Sperandio:
This means that the burst gives us information about the exploded star and its environs at various epoch, but what kind of information, Dr. Salvaterra, do they give us about the Cosmo as a whole:
Ruben Salvaterra:
With the formation of the first stars in the Universe, lights and photons impact the primordial hydrogen. The very bright early stars emit very energetic photons that begin to ionize the Intergalactic Medium separating the electrons from the protons in the hydrogen atom. The Universe in such a way becomes ionized and fully transparent the way it is nowadays. Clearly the study of the re-ionization epoch, via these bright GRBs used as far beacons, is fundamental to Cosmology.
Monica Sperandio
It is really a fantastic event and hopefully Swift, who has been designed also to catch these very distant bursts, will marvel us again.