Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Swift Observes An Unusual Bang In The Far Universe

05.04.2006


Almost 40 years have passed since top secret nuclear weapon warning satellites accidentally discovered bursts of high energy gamma rays coming from space. Although many thousands of gamma ray bursts (GRBs) have since been detected, the origin and nature of these bursts is still not well understood.



One example of an unusual gamma ray burst occurred on 1 August 2005, when instruments on board the NASA-UK-Italy Swift spacecraft detected a bizarre GRB, which displayed unprecedented behaviour. Results based on the Swift data are being presented today (Wednesday) at the RAS National Astronomy Meeting in Leicester by Massimiliano De Pasquale from Mullard Space Laboratory-UCL.

Gamma ray bursts take the form of a brilliant burst of radiation, followed by a slowly fading afterglow. This shallow decay in the X-ray and optical light curve usually lasts for several days after the high energy explosion.


Swift data have shown that, whatever the ‘central engine’ that powers the GRB may be, it does not switch off after a few seconds, but often produces fast flares of radiation and injects energy into the outflow for hours.

Scientists believe that most GRBs are thought to be the result of a black hole swallowing a large star. This process might take long enough to explain both the prompt emission of X-rays and gamma rays, the late flares and energy injection.

The remaining matter is launched outwards at a huge velocity, but the interstellar medium around the burst acts like a “brake” to this outflow, being heated in the process and producing the afterglow emission.

In the case of the August 2005 gamma ray burst, known as GRB050801 after its date of detection, there was a bright afterglow with a steady emission both in X-ray and optical wavelengths, without any initial, brilliant flare. This behaviour lasted for only 250 seconds after the end of the prompt emission, before the afterglow began the typical decline in brightness. This behaviour has never been observed before.

The flat emission both in X-ray and optical wavelengths gives some hints about the ‘central engine’ of this GRB.

“This feature might be explained if we assume that, rather than a black hole, the core of the star has shrunk its mass and its magnetic field into an object known as a magnetar,” said Massimiliano De Pasquale.

A magnetar is a form of neutron star, the remains of a collapsed star that was originally about 10 times more massive than the Sun. This extremely dense object typically has a radius of only 10 km but the same mass of the Sun.

Magnetars are thousands of times more magnetic than ordinary neutron stars, with a magnetic field 1,000 million million times stronger than the Earth’s. Only a few of these exotic objects are known.

“Such an object initially rotates very quickly, typically hundreds of times every second, but it slows down by irradiating its energy at the magnetic poles, like a lighthouse,” said De Pasquale. “This would keep the afterglow emission steady for a time scale similar to that observed for GRB 050801.

The joint analysis of data from the XRT and UVOT instruments on Swift has also allowed the team to determine the distance of GRB050801, which was previously unknown, by measuring the amount of light absorbed during its intergalactic travel en route to the Earth.

It turns out that the burst took place 9 billion light-years away, which means that the gamma rays, X-rays and light from the gamma ray burst were created and began their journey across the universe 4,500 million years before the Earth was born.

“The explosion produced the same amount of energy as the Sun produces during its entire lifetime of 10 billion years,” said Massimiliano De Pasquale.

Massimiliano De Pasquale | alfa
Further information:
http://www.nam2006.le.ac.uk/index.shtml
http://www.ras.org.uk

More articles from Physics and Astronomy:

nachricht Protecting the power grid: Advanced plasma switch for more efficient transmission
17.08.2018 | DOE/Princeton Plasma Physics Laboratory

nachricht Unraveling the nature of 'whistlers' from space in the lab
15.08.2018 | American Institute of Physics

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: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Quantum material is promising 'ion conductor' for research, new technologies

17.08.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>