__NOTOC__ GRB 080319B was a

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milli ...

(GRB) detected by the

Swift Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIFT, ...

satellite at 06:12 UTC on March 19, 2008. The burst set a new record for the farthest object that was observable with the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal ...

: it had a peak visual

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

of 5.7 and remained visible to human eyes for approximately 30 seconds. The magnitude was brighter than 9.0 for approximately 60 seconds. If viewed from 1 AU away, it would have had a peak apparent magnitude of −67.57 (21 quadrillion times brighter than the Sun seen from Earth).

Overview

The GRB's

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...

was measured to be 0.937, which means that the explosion occurred about 7.5 billion () years ago (the

lookback time Before Present (BP) years, or "years before present", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Becau ...

), and it took the light that long to reach Earth. This is roughly half the time since the

Big Bang The Big Bang event is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models of the Big Bang explain the evolution of the observable universe from the ...

. The first scientific paper submitted on the event suggested that the GRB could have easily been seen to a redshift of 16 (essentially to the time in the universe when stars were just being formed, well into the age of

reionization In the fields of Big Bang theory and cosmology, reionization is the process that caused matter in the universe to reionize after the lapse of the " dark ages". Reionization is the second of two major phase transitions of gas in the universe (t ...

) from a sub-meter sized

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...

equipped with near-

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

filters. The afterglow of the burst set a new record for the "most intrinsically bright object ever observed by humans in the universe", 2.5 million times brighter than the brightest supernova to date,

SN 2005ap SN 2005ap was an extremely energetic type Ic supernova in the galaxy SDSS J130115.12+274327.5. With a peak absolute magnitude of around −22.7, it is the second-brightest superluminous supernova yet recorded, twice as bright as the previo ...

. Evidence suggests that the afterglow was particularly bright because of its gamma jet pointing directly at Earth. This allowed an unprecedented examination of the jet structure, which appears to have consisted of a narrowly focused cone and a secondary wider one. If this is the norm for GRB jets, it follows that most GRB detections only capture the fainter wide cone, which means that most distant GRBs are too faint to detect with current telescopes. This would imply that GRBs are a far more common phenomenon than so far assumed. A record for the number of observed bursts with the same satellite on one day, four, was also set. This burst was named with the suffix B since it was the second burst detected that day. In fact, there were five GRBs detected in a 24-hour period, including GRB 080320. Until this gamma-ray burst event, the

Triangulum Galaxy The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC (''New General Catalogue)'' 598. With the D25 isophotal diameter of , the Triangulum Ga ...

, at a distance of about 2.9 million light years, was the most distant object visible to the naked eye. The galaxy remains the most distant permanent object viewable without aid. It was soon suggested that this spectacle be named the Clarke Event, as it first reached Earth just hours before the death of Arthur C. Clarke. The plot below shows the brightness in both the optical and at higher energy for the event. The first optical exposure started about 2 seconds before the source was first observed by the SWIFT telescope and lasted for 10 seconds. The emission in both curves then peaks at around 60 seconds before a long exponential decay.

References

Citations

* *

Database references

External links

Hubble Pinpoints Record-Breaking Explosion

SkyWatch Show 165: Brightest Explosion Ever Seen
-(mp3)
AAVSO Alert Notice 372 Possible naked-eye gamma-ray burst detected (GRB 080319B)

{{DEFAULTSORT:Grb 080319b 080319B Boötes 20080319

Overview

See also

References

Citations

Database references

External links