GRB 050904

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Image taken by the Southern Observatory for Astrophysical Research (SOAR) 4.1 m telescope showing the afterglow of GRB 050904 in the infrared range.

GRB 050904 is the name of a gamma-ray flash that was observed on September 4, 2005 at 01:51:44 UTC with the help of NASA's Swift satellite .

Since the afterglow of the event (in the near infrared) was also optically recorded by the terrestrial telescope SOAR, the position and redshift are known. The gamma-ray flash occurred at a distance of 12.7 billion light years (z = 6.29) and could be observed in the constellation Pisces at the position RA = 00h54m41s Dec = N14 ° 08′17 ″. The gamma-ray flash lasted about 200 seconds and is one of the long GRBs associated with supernovae . Until the discovery of the gamma-ray burst GRB 080913 in 2008, it was the most distant GRB from Earth, and thus one of the oldest documented events in the universe . The duration of 200 seconds is a result of the cosmological expansion. For a close observer, the event would have been a factor faster, i.e. in less than half a minute.

observation

Counting rate based on data from NASA's Swift satellite. The graphic above is for the strongly redshifted eruption on September 4, 2005 (GRB 050904). The graphic below shows a typical outbreak as a comparison (GRB 050326).

Forerunner star

The cause of the gamma-ray flash was presumably a giant star whose existence was ended with a huge explosion ancient times. This is what researchers report in an issue of the British journal "Nature". In the explosion, 300 times more energy was released within a few minutes than the sun would give off in its entire life of 10 billion years. In general, scientists suspect that long gamma-ray bursts can be traced back to extremely massive, collapsing stars, so-called hypernovae . The scientists hope that the data will provide new insights into the formation of the first stars and galaxies in the young universe.

distance

The gamma-ray burst set a new distance record for GRBs at a distance of around 12.7 billion light years and is the fourth oldest documented event in the universe to date. In terms of distance, it is only exceeded by the GRB 080913 registered on September 13, 2008 and the GRB 090423 discovered on April 23, 2009. The gigantic collapse occurred less than 900 million years after the Big Bang , a point in time when the universe had just reached about 6% of its present age and the first stars and galaxies had just formed.

The distance record for a cosmic explosion surpassed the previous one by nearly 500 million light years. The previous record holder was 12.3 billion light years away (z = 4.5).

RHESSI Counting rate as a function of time

Afterglow

The first indication of its removal brought the knowledge that the afterglow could not be measured in the optical range , but wavelengths in the infrared range were recorded. The large distance to the GRB means that the radiation is shifted to wavelengths of lower energy due to the redshift . Because of the absorption caused by matter between the gamma-ray burst and the earth , the emitted UV and gamma radiation do not reach us .

literature

  • David Alexander Kann, Steve Schulze and Sylvio Klose: Cosmic gamma ray bursts. New discoveries and new puzzles in the era of the Swift gamma satellite . Stars and Space 12/2007, p. 42

Individual evidence

  1. ↑ NASA: Most distant GRB December 9, 2005
  2. ^ Paul Scherrer Institute (PSI), Laboratory for Astrophysics: - GRBs 2005
  3. ↑ Swift: Gamma ray burst Real-time Sky Map - based on data from NASA's Swift satellite
  4. ↑ NASA: NASA's Swift Catches Farthest Ever Gamma-Ray Burst - September 13, 2008