Robotic Telescope unravels mystery of cosmic blasts

Mar 15, 2007
Figure showing the links between the gamma ray burst detection and follow up observations. (1) Gamma Ray Burst, GRB 060418, explodes and emits high-energy gamma rays. (2) and (3) Swift satellite detects gamma rays and sends notification of sky location to ground telescopes. (4) Liverpool Telescope (LT) on mountain top on Canary island of La Palma receives notification and immediately points to correct part of sky to begin to capture optical light from GRB afterglow. (5) Polarisation image taken with LT polarimeter, RINGO, is transmitted to the Astrophysics Institute at Liverpool John Moores University for analysis by scientists. Credit: Dr Carole Mundell, Liverpool John Moores University.

Scientists have used the world's largest robotic telescope to make the earliest-ever measurement of the optical polarisation of a Gamma Ray Burst (GRB) just 203 seconds after the start of the cosmic explosion. This finding, which provides new insight into GRB physics, is published in Science today.

The scientists from Liverpool John Moores University and colleagues in the UK, Italy, France and Slovenia used the Liverpool Telescope on the island of La Palma and its novel new polarimeter, RINGO, to perform the measurement following detection of the burst by NASA's Swift satellite.

Gamma Ray Bursts are the most instantaneously powerful explosions in the Universe and are identified as brief, intense and completely unpredictable flashes of high energy gamma rays on the sky. They are thought to be produced by the death throes of a massive star and signal the birth of a new black hole or neutron star (magnetar) and ejection of an ultra-high speed jet of plasma. Until now, the composition of the ejected material has remained a mystery and, in particular the importance of magnetic fields has been hotly debated by GRB scientists.

The Liverpool measurement was obtained nearly 100 times faster than any previously published optical polarisation measurement for a GRB afterglow and answers some fundamental questions about the presence of magnetic fields.

Principal author of the Science paper and GRB team leader Dr Carole Mundell of the Astrophysics Research Institute, Liverpool John Moores University, said "Our new measurements, made shortly after the Gamma Ray Burst, show that the level of polarisation in the afterglow is very low. Combined with our knowledge of how the light from this explosion faded, this rules-out the presence of strong magnetic fields in the emitting material flowing out from the explosion - a key element of some theories of GRBs."

The so-called optical afterglow is thought to originate from light emitted when this ejected material impacts the gas surrounding the star. In the first few minutes after the initial burst of gamma rays, the optical light carries important clues to the origin of these catastrophic explosions; capturing this light at the earliest possible opportunity and measuring its properties is ideally suited to the capabilities of large robotic telescopes like the Liverpool Telescope.

Lord Martin Rees, Astronomer Royal and President of the Royal Society said "We are still flummoxed about the underlying trigger' for gamma ray bursts, and why they sometimes emit bright flashes of light. Theorists have a lot of tentative ideas, and these observations narrow down the range of options."

Professor Keith Mason, Chief Executive of PPARC and UK lead investigator on Swift's Ultra Violet/Optical Telescope, said, "This result demonstrates well the effectiveness of Swift's rapid response alert system, allowing robotic telescopes, such as the Liverpool Telescope, to follow up gamma ray bursts within seconds, furthering our knowledge with each detection."

Source: PPARC

Explore further: 'Blockbuster' science images

add to favorites email to friend print save as pdf

Related Stories

Glimpsing the infrastructure of a gamma-ray burst jet

Dec 04, 2013

(Phys.org) —A new study using observations from a novel instrument provides the best look to date at magnetic fields at the heart of gamma-ray bursts, the most energetic explosions in the universe. An international ...

Liverpool Telescope plans double-sized successor

Jul 02, 2013

(Phys.org) —Planning is underway for a successor to the world's largest fully robotic telescope. The Liverpool Telescope (LT) is a 2-metre optical telescope located on La Palma that has been in operation ...

Magnetic Power Revealed in Gamma-Ray Burst Jet

Dec 09, 2009

(PhysOrg.com) -- A specialized camera on a telescope operated by U.K. astronomers from Liverpool has made the first measurement of magnetic fields in the afterglow of a gamma-ray burst (GRB). The result is ...

'Naked Eye' Gamma Ray Burst Was Aimed Squarely At Earth

Sep 10, 2008

(PhysOrg.com) -- The brightest explosion ever seen was observed in March this year. Now a team of astronomers from around the world, including the University of Leicester, the Mullard Space Science Laboratory ...

Death of massive star creates brightest burst ever seen

Mar 20, 2008

Gamma-Ray Bursts are the most powerful explosive events in the Universe. They occur in far-off galaxies and so are usually faint. But on the morning of March 19th 2008 the Swift satellite found a burst which ...

Recommended for you

'Blockbuster' science images

Nov 21, 2014

At this point, the blockbuster movie Interstellar has created such a stir that one would almost have to be inside a black hole not to know about it. And while the science fiction thriller may have taken some ...

Estimating the magnetic field of an exoplanet

Nov 20, 2014

Scientists developed a new method which allows to estimate the magnetic field of a distant exoplanet, i.e., a planet, which is located outside the Solar system and orbits a different star. Moreover, they ...

It's filamentary: How galaxies evolve in the cosmic web

Nov 20, 2014

How do galaxies like our Milky Way form, and just how do they evolve? Are galaxies affected by their surrounding environment? An international team of researchers, led by astronomers at the University of ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.