Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

DCU astronomers measure the speed of the most powerful explosions in the Universe

15.06.2007
DCU astronomers in collaboration with a team of international researchers have measured the velocity of explosions known as Gamma-Ray Bursts (GRBs). These powerful events occur in distant galaxies and signal the death of very massive stars that collapse into black holes.

GRBs are the most powerful energy releases since the Big Bang and are so bright that they rival the whole Universe in luminosity. They last for a very short time, from less than a second to a few minutes. In order to emit such incredible power in so little time, the exploding material must be moving at a speed comparable with that of light, which is 300,000 km per second.

The initial readings for two such GRBs were recorded by a satellite gamma-ray telescope orbiting the Earth, on 18 April and on 7 June 2006. In a matter of a few seconds, their position was transmitted to the ground, and the robotic 'REM' Telescope at the European Southern Observatory (ESO; La Silla, Chile) began to observe these GRB fields, detecting near-infrared afterglows and monitoring the evolution of their luminosity as a function of time (the light curve).

The two gamma-ray bursts were located in far-away galaxies, at 9.3 and 11.5 billion light-years respectively. For both events, the light curve was initially rising, then reached a peak, and eventually started to decline, as it is expected for GRB afterglows. The peak is, however, only rarely detected. Its determination is very important and very exciting, since it allows a direct measurement of the expansion velocity of the explosion.

"The burst of 7 June 2006 exploded when we were at a GRB Conference in Venice. When we looked at the first data and saw that the light curve was rising, we were so excited that we performed the data reduction in real time. As a result, the afterglow light curve could be shown at the conference just a few hours later" recalls Susanna Vergani (postgraduate student, DCU-DIAS).

For both bursts, the velocity turns out to be very close to the speed of light, to be precise 99.9997% of this value. Astronomers use a special number, called Lorentz factor, to express these high velocities. Objects moving much slower than light have a Lorentz factor of about 1, while for these two GRBs it is about 400.

"This is an important result, which confirms the 'fireball' theory that has been put forward to explain these exceptional explosions and, interestingly, has been achieved with a small-size telescope" says Prof. Evert Meurs, Director of Dunsink Observatory and leader of the Irish team involved in this project.

Shane Kenny | alfa
Further information:
http://www.dcu.ie

More articles from Physics and Astronomy:

nachricht SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute

nachricht New survey hints at exotic origin for the Cold Spot
26.04.2017 | Royal Astronomical Society

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>