GRB 080319B

The very bright afterglow of the gamma-ray flash GRB 080319B, recorded by the XRT X-ray telescope (left) and the UVOT optical / ultraviolet telescope (right) of the Swift satellite. This was by far the brightest afterglow of a gamma-ray flash ever observed.

GRB 080319B is the name of a gamma-ray burst ( English gamma-ray burst , short GRB ), which on March 19, 2008 at 6:12:49 pm UTC by NASA satellites Swift was discovered. It was the second of a total of four gamma-ray flashes discovered that day (within 24 hours there were even five, GRB 080320 was added).

The gamma-ray flash occurred at a distance of about 7.5 billion light years ( z = 0.937) and was in the constellation Bear Guardian about 5 ′ from the star γ Bootis (Seginus) at the J2000.0 position RA = 14h 31m 41s / Dec = + 36 ° 18 ′ 09 ″ to be observed. The optical afterglow of the gamma-ray flash had a maximum apparent brightness of 5.76 mag and an absolute brightness of −36 mag and is therefore more luminous than all previously observed supernovae and GRB afterglow. It is the most distant object that has ever been seen with the naked eye.

The reason why an energy burst was observed that did not destroy its immediate (cosmic) environment at the same time is believed to be that these gamma-ray bursts propagate within a pointed cone-shaped jet. With GRB 080319B it was observed that within this radiation cone there was another, even more pointed cone in which the energy was concentrated even more. In fact, the diameter of the beam from GRB 080319B was only about 0.4 arc degrees, which is on the order of the visible diameter of the sun.

Superlatives

Brightest afterglow

Gamma-ray bursts are among the most powerful known bursts of energy in the universe. With an absolute brightness of −36 mag, the observed afterglow of the gamma-ray flash was more than 2.5 million times brighter than the previously brightest supernovae SN 2005ap and SN 2006gy .

visibility

The majority of the energy in a gamma-ray burst is emitted in the form of gamma radiation. When the material ejections (plasma jets) that are emitted at almost the speed of light collide with the surrounding gas, shock fronts and afterglow arise, which can also be observed in the visible spectrum. With this GRB, this afterglow of around 5.8 mag was so bright for the first time that it could be seen with the naked eye. The afterglow was measured for 30 seconds at a corresponding strength.

Prior to March 19, 2008, the Triangular Nebula (M33, the Triangulum Galaxy) was the most distant object visible to the naked eye. The distance of the Triangle Nebula is 2.8 million light years. The gamma-ray explosion GRB 080319B is more than 2500 times farther from Earth.

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. ↑ Helmut Dannerbauer: WANTED - Who has seen GRB 080319B? In: SciLogs , March 22, 2008.
2. ↑ ^{a b} "Pi of the sky" observation of GRB080319B. ( Memento of the original from July 27, 2012 on WebCite ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. In: π of the Sky (English). 
3. ↑ GCN Circular: GRB 080319B: TORTORA light curve (Correction) April 1, 2008 (English).
4. ↑ JS Bloom et al .: Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion. In: arXiv , March 24, 2008 (English).
5. ↑ www.nasa.gov: NASA Satellite Detects Record Gamma Ray Burst Explosion Halfway Across Universe . March 20, 2008
6. ↑ David Palmer: GCN CIRCULAR - GRB 080319B: Swift detection of an intense burst with a bright optical counterpart . March 19, 2008, accessed March 21, 2008.
7. ^ Naked-eye 'gamma-ray burst was aimed squarely at Earth. In: e! Science News , September 11, 2008.
8. ^ Govert Schilling: Universe's most powerful blast visible to the naked eye. In: New Scientist , March 21, 2008 (English).
9. ^ "Pi of the Sky" observation of GRB080319B - the brightest ever gamma ray burst. ( Memento of the original from July 27, 2012 on WebCite ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. In: π of the Sky (English). 
10. ↑ TORTORA data: Corrected TORTORA light curve April 1, 2008