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 Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore

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: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Porous crystalline materials: TU Graz researcher shows method for controlled growth

07.12.2016 | Materials Sciences

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>