NASA satellite records early stage of gamma-ray burst

March 3rd, 2009 - 1:44 pm ICT by ANI  

Washington, March 3 (ANI): A team of astronomers, using a telescope aboard the NASA Swift satellite, have captured information from the early stages of a gamma-ray burst, the most violent and luminous explosions occurring in the Universe since the Big Bang.

By using Swifts Ultraviolet/Optical Telescope (UVOT), the astronomers were able to obtain an ultraviolet spectrum of a GRB just 251 seconds after its onset, the earliest ever captured.

The gamma-ray burst observed on this occasion originated in a galaxy 8 billion light years from Earth

Further use of the instrument in this way will allow them to calculate the distance and brightness of GRBs within a few hundred seconds of their initial outburst, and gather new information about the causes of bursts and the galaxies they originate from.

It is currently thought that some GRBs are caused by immense explosions following the collapse of the core of a rapidly rotating, high-mass star into a black hole, but there are still many mysteries surrounding them.

The UVOTs wavelength range, coupled with the fact that Swift is a space observatory with a speedy response rate, unconstrained by time of day or weather, has allowed us to collect this early ultraviolet spectrum, said Martin Still from the Mullard Space Science Laboratory (MSSL) at University College London (UCL).

Paul Kuin, also from MSSL, who works on the calibration of the UVOT instrument, explained that, By looking at these earlier moments of gamma-ray bursts, we will not only be able to better calculate things such as the luminosity and distance of a burst, but to find out more about the galaxies that play host to them and the impact these explosions have on their environments.

Once this new technique is applied to much brighter bursts, well have a wealth of new data, he added.

According to Massimiliano De Pasquale, a GRB scientist of the UVOT team from MSSL, The UVOT instrument is particularly suited to study bursts with an average to high redshift - a part of the ultraviolet spectrum that is difficult for even the very big ground-based telescopes to study.

Using UVOT with Swift, we can now find redshifts for bursts that were difficult to capture in the past and find out more about their distant host galaxies, about ten billion light years away, he added.

The new spectrum has not only allowed us to determine the distance of the gamma-ray bursts host galaxy but has revealed the density of its hydrogen clouds. Learning more about these far-away galaxies helps us to understand how they formed during the early universe, said Kuin. (ANI)

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