Gamma-ray burst: Difference between revisions
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The nature of the longer-wavelength afterglow emission (ranging from [[X-ray]] through [[radio waves|radio]]) that follows gamma-ray bursts is better understood. Any energy released by the explosion not radiated away in the burst itself takes the form of matter or energy moving outward at nearly the speed of light. As this matter collides with the surrounding [[interstellar gas]], it creates a [[relativistic speed|relativistic]] [[shock wave]] that then propagates forward into interstellar space. A second shock wave, the reverse shock, may propagate back into the ejected matter. Extremely energetic electrons within the shock wave are accelerated by strong local magnetic fields and radiate as [[synchrotron]] emission across most of the [[electromagnetic spectrum]].<ref>[[#Meszaros|Meszaros 1997]]</ref><ref>[[#Sari98|Sari 1998]]</ref> This model has generally been successful in modeling the behavior of many observed afterglows at late times (generally, hours to days after the explosion), although there are difficulties explaining all features of the afterglow very shortly after the gamma-ray burst has occurred.<ref>[[#Nousek|Nousek 2006]]</ref> |
The nature of the longer-wavelength afterglow emission (ranging from [[X-ray]] through [[radio waves|radio]]) that follows gamma-ray bursts is better understood. Any energy released by the explosion not radiated away in the burst itself takes the form of matter or energy moving outward at nearly the speed of light. As this matter collides with the surrounding [[interstellar gas]], it creates a [[relativistic speed|relativistic]] [[shock wave]] that then propagates forward into interstellar space. A second shock wave, the reverse shock, may propagate back into the ejected matter. Extremely energetic electrons within the shock wave are accelerated by strong local magnetic fields and radiate as [[synchrotron]] emission across most of the [[electromagnetic spectrum]].<ref>[[#Meszaros|Meszaros 1997]]</ref><ref>[[#Sari98|Sari 1998]]</ref> This model has generally been successful in modeling the behavior of many observed afterglows at late times (generally, hours to days after the explosion), although there are difficulties explaining all features of the afterglow very shortly after the gamma-ray burst has occurred.<ref>[[#Nousek|Nousek 2006]]</ref> |
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==Rates and potential effects on life== |
==Rates and potential effects on earth life== |
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All the bursts astronomers have recorded so far have come from distant galaxies and been harmless on the ground of earh, but if one occurred within our galaxy and if aimed straight at us, the effects could be devastating.Currently orbiting satellites detect an average of about one gamma-ray burst per day.<br /> |
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Measuring the exact rate is difficult, but for a galaxy of approximately the same size as the [[Milky Way]], the expected rate (for long GRBs) is about one burst every 100,000 to 1,000,000 years.Only a small percentage of these would be beamed towards Earth. Estimates of rates of short GRBs are even more uncertain because of the unknown degree of collimation, but are probably comparable.<br /> |
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Gamma-ray bursts are thought to emerge mainly from the poles of a collapsing star. This creates two, oppositely shining beams of radiation shaped like narrow cones. Planets not lying in these cones would be comparatively safe; the chief worry is for those that do.<br /> |
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=== Potential effect comparing [[Deinococcus radiodurans]] === |
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* The first is a flash of [[gamma rays]]. The flash can damage even the most radioactive resistant organisms known, the bacterium Deinococcus radiodurans. This bacteria can take 2000 times more radiation but prove to kill humans.<br /> |
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* For a planet with a thin atmosphere, the gamma flash could kill 90 percent of D.radiodurans from distances up to three times our galaxy’s width. A thick atmosphere would protect the microbes from this, but not necessarily from a second component of the beam, [[ultraviolet radiation]]<ref>Galante and Horvath </ref>.<br /> |
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* For thick atmosphere planets, a gamma-ray burst’s ultraviolet rays would kill 90 percent of D. radiodurans at distances ranging from 13,000 to 62,000 light years.<br /> |
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* If life survived that onslaught would have to contend with a third effect, depletion of the atmosphere’s protective ozone layer by the burst. This would kill 90 percent of D. radiodurans at up to 40 percent of the distance across the Milky Way<ref>http://www.world-science.net/exclusives/070226_grb-life.htm</ref>.<br /> |
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=== Hypothetical effects of Gamma ray from past === |
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A gamma-ray burst in the Milky Way, if close enough to Earth and beamed towards it, could have significant effects on the [[biosphere]]. The absorption of radiation in the atmosphere would cause [[photodissociation]] of [[nitrogen]], generating [[nitric oxide]] that would act as a catalyst to destroy [[ozone]].<ref>[[#Thorsett|Thorsett 1995]]</ref> According to a 2004 study, a GRB at a distance of about a [[parsec|kiloparsec]] (approximately 3,000 light-years) could destroy up to half of Earth's [[ozone layer]]; the direct UV irradiation from the burst combined with additional solar UV radiation passing through the diminished ozone layer could then have potentially significant impacts on the [[food chain]] and potentially trigger a [[mass extinction]].<ref name="Melott2004"/><ref name="ancient">[[#Wanjek|Wanjek 2005]]</ref> The authors estimate that one such burst is expected per billion years, and hypothesize that the [[Ordovician–Silurian extinction event]] could have been the result of such a burst, although there is no current evidence to support this idea. |
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GRBs close enough to affect life in some way might occur once every five million years or so - around a thousand times since life began<ref>New Scientist print edition, 15 December 2001, p 10). John Scalo and Craig Wheeler of the University of Texas at Austin</ref>.<br /> |
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Ordovician Mass Extinction 450 million years ago. The Earth’s second most devastating extinction is hypothetically caused by past GRB Pattern of extinctions in the [[late Ordovician]] species of [[trilobite]] that spent some of their lives in the plankton layer near the ocean surface were much harder hit than deep-water dwellers, which tended to stay put within quite restricted areas. Usually it is the more widely spread species that fare better in extinction says this unusual pattern could be explained by a GRB, which would probably devastate creatures living on land and near the ocean surface, but leave deep-sea creatures relatively unharmed<ref>Adrian Melott of the University of Kansas in Lawrence</ref><ref>Bruce Lieberman, a specialist in fossil trilobites also at the University of Kansas, and other colleagues</ref>. |
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=== Hypothetical effects of gamma ray burst in future === |
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The real danger comes from the [[Wolf-Rayet stars]] regarded by astronomers as ticking bombs<ref>Peter Tuthill, an astronomer at the University of Sydney</ref>. When it will change to supernova it may emmit intense beam of gamma ray, if earth comes to lie in the beam zone devastating effects may happen. Gamma rays would not penetrate Earth's atmosphere well to burn the ground, but they would chemically damage the [[stratosphere]]<br /> |
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If [[WR 104]] were to hit earth with a burst 10 seconds or long, its gamma rays could deplete about 25 percent of the world's [[ozone layer]].It would create [[mass extinction]],starvation and food chain depletion. Earth side facing the GRB may face [[radiation exposure]] and humans on that side |
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will have radiation sickness cosmic rays coming from space to earth without ozone will be more [[space disasters]]<ref>Adrian Melott of the University of Kansas in Lawrence</ref>.<br /> |
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=== Events after exposure to the gamma ray burst on earth's atmosphere === |
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<gallery> |
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File:Dn4198-1 536.jpg|After effects of gamma ray burst |
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</gallery> |
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There are strong indications that long gamma-ray bursts preferentially or exclusively occur in regions of low [[metallicity]]. Because the Milky Way has been metal-rich since before the Earth formed, this effect may diminish or even eliminate the possibility that a long gamma-ray burst has occurred within the Milky Way within the past billion years.<ref name="Stanek"/> No such metallicity biases are known for short gamma-ray bursts. Thus, depending on their local rate and beaming properties, the possibility for a nearby event to have had a large impact on Earth at some point in geological time may still be significant.<ref>[[#Ejzak|Ejzak 2007]]</ref> |
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Most likely Earth may absorb and soak gamma rays but its energy may cause chemical reaction for [[oxygen]] and [[nitrogen]] [[molecules]] which may create [[nitrogen oxide]] then [[nitrogen dioxide]] gas causing [[photochemical smog]]. Burst may produce enough of the gas to cover sky and darken it. Gas will prevent sunlight to enter earth and even deplete rest of the [[ozone layer]] thus exposing whole of the earth to all types of [[cosmic radiation]]<ref>Adrian Melott of the University of Kansas in Lawrence</ref> |
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==See also== |
==See also== |
Revision as of 13:41, 3 July 2011
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/63/Gamma_ray_burst.jpg/300px-Gamma_ray_burst.jpg)
Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the most luminous electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several minutes, although a typical burst lasts 20–40 seconds. The initial burst is usually followed by a longer-lived "afterglow" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, micro and radio).
Most observed GRBs are believed to consist of a narrow beam of intense radiation released during a supernova event, as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole. A subclass of GRBs (the "short" bursts) appear to originate from a different process, possibly the merger of binary neutron stars.
The sources of most GRBs are billions of light years away from Earth, implying that the explosions are both extremely energetic (a typical burst releases as much energy in a few seconds as the Sun will in its entire 10-billion-year lifetime) and extremely rare (a few per galaxy per million years[1]). All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way. It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event.[2]
GRBs were first detected in 1967 by the Vela satellites, a series of satellites designed to detect covert nuclear weapons tests. Hundreds of theoretical models were proposed to explain these bursts in the years following their discovery, such as collisions between comets and neutron stars.[3] Little information was available to verify these models until the 1997 detection of the first X-ray and optical afterglows and direct measurement of their redshifts using optical spectroscopy. These discoveries, and subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs, definitively placing them in distant galaxies and connecting long GRBs with the deaths of massive stars.
History
Gamma-ray bursts were first observed in the late 1960s by the U.S. Vela satellites, which were built to detect gamma radiation pulses emitted by nuclear weapons tested in space. The United States suspected that the USSR might attempt to conduct secret nuclear tests after signing the Nuclear Test Ban Treaty in 1963. On July 2, 1967, at 14:19 UTC, the Vela 4 and Vela 3 satellites detected a flash of gamma radiation unlike any known nuclear weapons signature.[4] Uncertain what had happened but not considering the matter particularly urgent, the team at the Los Alamos Scientific Laboratory, led by Ray Klebesadel, filed the data away for investigation. As additional Vela satellites were launched with better instruments, the Los Alamos team continued to find inexplicable gamma-ray bursts in their data. By analyzing the different arrival times of the bursts as detected by different satellites, the team was able to determine rough estimates for the sky positions of sixteen bursts[4] and definitively rule out a terrestrial or solar origin. The discovery was declassified and published in 1973 as an Astrophysical Journal article entitled "Observations of Gamma-Ray Bursts of Cosmic Origin".[5]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/BATSE_2704.jpg/250px-BATSE_2704.jpg)
Many theories were advanced to explain these bursts, most of which posited nearby sources within the Milky Way Galaxy. Little progress was made until the 1991 launch of the Compton Gamma Ray Observatory and its Burst and Transient Source Explorer (BATSE) instrument, an extremely sensitive gamma-ray detector. This instrument provided crucial data indicating that the distribution of GRBs is isotropic—not biased towards any particular direction in space, such as toward the galactic plane or the galactic center.[6] Because of the flattened shape of the Milky Way Galaxy, sources within our own galaxy would be strongly concentrated in or near the Galactic plane. The absence of any such pattern in the case of GRBs provided strong evidence that gamma-ray bursts must come from beyond the Milky Way.[7][8][9] However, some Milky Way models are still consistent with an isotropic distribution.[10]
For decades after the discovery of GRBs, astronomers searched for a counterpart: any astronomical object in positional coincidence with a recently observed burst. Astronomers considered many distinct classes of objects, including white dwarfs, pulsars, supernovae, globular clusters, quasars, Seyfert galaxies, and BL Lac objects.[11] All such searches were unsuccessful,[nb 1] and in a few cases particularly well-localized bursts (those whose positions were determined with what was then a high degree of accuracy) could be clearly shown to have no bright objects of any nature consistent with the position derived from the detecting satellites. This suggested an origin of either very faint stars or extremely distant galaxies.[12][13] Even the most accurate positions contained numerous faint stars and galaxies, and it was widely agreed that final resolution of the origins of cosmic gamma-ray bursts would require both new satellites and faster communication.[14]
Several models for the origin of gamma-ray bursts postulated[15] that the initial burst of gamma rays should be followed by slowly fading emission at longer wavelengths created by collisions between the burst ejecta and interstellar gas. Early searches for this "afterglow" were unsuccessful, largely due to the difficulties in observing a burst's position at longer wavelengths immediately after the initial burst. The breakthrough came in February 1997 when the satellite BeppoSAX detected a gamma-ray burst (GRB 970228[nb 2]) and when the X-ray camera was pointed towards the direction from which the burst had originated, it detected fading X-ray emission. The William Herschel Telescope identified a fading optical counterpart 20 hours after the burst.[16] Once the GRB faded, deep imaging was able to identify a faint, distant host galaxy at the location of the GRB as pinpointed by the optical afterglow.[17]
Because of the very faint luminosity of this galaxy, its exact distance was not measured for several years. Well before then, another major breakthrough occurred with the next event registered by BeppoSAX, GRB 970508. This event was localized within four hours of its discovery, allowing research teams to begin making observations much sooner than any previous burst. The spectrum of the object revealed a redshift of z = 0.835, placing the burst at a distance of roughly 6 billion light years from Earth.[18] This was the first accurate determination of the distance to a GRB, and together with the discovery of the host galaxy of 970228 proved that GRBs occur in extremely distant galaxies.[19] Within a few months, the controversy about the distance scale ended: GRBs were extragalactic events originating within faint galaxies at enormous distances. The following year, GRB 980425 was followed within a day by a coincident bright supernova (SN 1998bw), indicating a clear connection between GRBs and the deaths of very massive stars. This burst provided the first strong clue about the nature of the systems that produce GRBs.[20]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/64/Swift_spacecraft.jpg/220px-Swift_spacecraft.jpg)
BeppoSAX functioned until 2002 and CGRO (with BATSE) was deorbited in 2000. However, the revolution in the study of gamma-ray bursts motivated the development of a number of additional instruments designed specifically to explore the nature of GRBs, especially in the earliest moments following the explosion. The first such mission, HETE-2,[21] launched in 2000 and functioned until 2006, providing most of the major discoveries during this period. One of the most successful space missions to date, Swift, was launched in 2004 and as of 2011 is still operational.[22][23] Swift is equipped with a very sensitive gamma ray detector as well as on-board X-ray and optical telescopes, which can be rapidly and automatically slewed to observe afterglow emission following a burst. More recently, the Fermi mission was launched carrying the Gamma-Ray Burst Monitor, which detects bursts at a rate of several hundred per year, some of which are bright enough to be observed at extremely high energies with Fermi's Large Area Telescope. Meanwhile, on the ground, numerous optical telescopes have been built or modified to incorporate robotic control software that responds immediately to signals sent through the Gamma-ray Burst Coordinates Network. This allows the telescopes to rapidly repoint towards a GRB, often within seconds of receiving the signal and while the gamma-ray emission itself is still ongoing.[24][25]
New developments over the past few years include the recognition of short gamma-ray bursts as a separate class (likely due to merging neutron stars and not associated with supernovae), the discovery of extended, erratic flaring activity at X-ray wavelengths lasting for many minutes after most GRBs, and the discovery of the most luminous (GRB 080319B) and the former most distant (GRB 090423) objects in the universe. The most distant known GRB, GRB 090429B, is not the most distant known object in the universe.
Classification
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/ef/GRB_BATSE_12lightcurves.png/200px-GRB_BATSE_12lightcurves.png)
While most astronomical transient sources have simple and consistent time structures (typically a rapid brightening followed by gradual fading, as in a nova or supernova), the light curves of gamma-ray bursts are extremely diverse and complex.[26] No two gamma-ray burst light curves are identical,[27] with large variation observed in almost every property: the duration of observable emission can vary from milliseconds to tens of minutes, there can be a single peak or several individual subpulses, and individual peaks can be symmetric or with fast brightening and very slow fading. Some bursts are preceded by a "precursor" event, a weak burst that is then followed (after seconds to minutes of no emission at all) by the much more intense "true" bursting episode.[28] The light curves of some events have extremely chaotic and complicated profiles with almost no discernible patterns.[14]
Although some light curves can be roughly reproduced using certain simplified models,[29] little progress has been made in understanding the full diversity observed. Many classification schemes have been proposed, but these are often based solely on differences in the appearance of light curves and may not always reflect a true physical difference in the progenitors of the explosions. However, plots of the distribution of the observed duration[nb 3] for a large number of gamma-ray bursts show a clear bimodality, suggesting the existence of two separate populations: a "short" population with an average duration of about 0.3 seconds and a "long" population with an average duration of about 30 seconds.[30] Both distributions are very broad with a significant overlap region in which the identity of a given event is not clear from duration alone. Additional classes beyond this two-tiered system have been proposed on both observational and theoretical grounds.[31][32][33][34]
Long gamma-ray bursts
Most observed events have a duration of greater than two seconds and are classified as long gamma-ray bursts. Because these events constitute the majority of the population and because they tend to have the brightest afterglows, they have been studied in much greater detail than their short counterparts. Almost every well-studied long gamma-ray burst has been linked to a galaxy with rapid star formation, and in many cases to a core-collapse supernova as well, unambiguously associating long GRBs with the deaths of massive stars.[35] Long GRB afterglow observations, at high redshift, are also consistent with the GRB having originated in star-forming regions.[36]
A unique gamma ray emission event, Sw 1644+57, lasting more than two and a half months was observed starting March 28, 2011, originating from the center of a small galaxy at redshift z = 0.3534. The event is interpreted as a supermassive black hole devouring a star, and emitting its beam of radiation towards Earth. It could thus be viewed as a temporarily active blazar (a type of quasar).[37][38][39]
Short gamma-ray bursts
Events with a duration of less than about two seconds are classified as short gamma-ray bursts. Until 2005, no afterglow had been successfully detected from any short event and little was known about their origins. Since then, several dozen short gamma-ray burst afterglows have been detected and localized, several of which are associated with regions of little or no star formation, such as large elliptical galaxies and the central regions of large galaxy clusters.[40][41][42] This rules out a link to massive stars, confirming that short events are physically distinct from long events. In addition, there has been no association with supernovae.[43] The true nature of these objects (or even whether the current classification scheme is accurate) remains unknown, although the leading hypothesis is that they originate from the mergers of binary neutron stars.[44] A small fraction of short gamma-ray bursts are probably produced by giant flares from soft gamma repeaters in nearby galaxies.[45][46]
Energetics and beaming
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/83/GRB080319B_illustration_NASA.jpg/250px-GRB080319B_illustration_NASA.jpg)
Gamma-ray bursts are very bright as observed from Earth despite their typically immense distances. An average long GRB has a bolometric flux comparable to a bright star of our galaxy despite a distance of billions of light years (compared to a few tens of light years for most visible stars). Most of this energy is released in gamma rays, although some GRBs have extremely luminous optical counterparts as well. GRB 080319B, for example, was accompanied by an optical counterpart that peaked at a visible magnitude of 5.8,[47] comparable to that of the dimmest naked-eye stars despite the burst's distance of 7.5 billion light years. This combination of brightness and distance requires an extremely energetic source. Assuming the gamma-ray explosion to be spherical, the energy output of GRB 080319B would be within a factor of two of the rest-mass energy of the Sun (the energy which would be released were the Sun to be converted entirely into radiation.) [48]
No known process in the Universe can produce this much energy in such a short time. However, gamma-ray bursts are thought to be highly focused explosions, with most of the explosion energy collimated into a narrow jet traveling at speeds exceeding 99.995% of the speed of light.[49][50] The approximate angular width of the jet (that is, the degree of beaming) can be estimated directly by observing the achromatic "jet breaks" in afterglow light curves: a time after which the slowly decaying afterglow abruptly begins to fade rapidly as the jet slows down and can no longer beam its radiation as effectively.[51][52] Observations suggest significant variation in the jet angle from between 2 and 20 degrees.[53]
Because their energy is strongly beamed, the gamma rays emitted by most bursts are expected to miss the Earth and never be detected. When a gamma-ray burst is pointed towards Earth, the focusing of its energy along a relatively narrow beam causes the burst to appear much brighter than it would have been were its energy emitted spherically. When this effect is taken into account, typical gamma-ray bursts are observed to have a true energy release of about 1044 J, or about 1/2000 of a Solar mass energy equivalent.[53] This is comparable to the energy released in a bright type Ib/c supernova (sometimes termed a "hypernova") and within the range of theoretical models. Very bright supernovae have been observed to accompany several of the nearest GRBs.[20] Additional support for strong beaming in GRBs has come from observations of strong asymmetries in the spectra of nearby type Ic supernova[54] and from radio observations taken long after bursts when their jets are no longer relativistic.[55]
Short GRBs appear to come from a lower-redshift (i.e. less distant) population and are less luminous than long GRBs.[56] The degree of beaming in short bursts has not been accurately measured, but as a population they are likely less collimated than long GRBs[57] or possibly not collimated at all in some cases.[58]
Progenitors
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/be/Wolf_rayet2.jpg/220px-Wolf_rayet2.jpg)
Because of the immense distances of most gamma-ray burst sources from Earth, identification of the progenitors, the systems that produce these explosions, is particularly challenging. The association of some long GRBs with supernovae and the fact that their host galaxies are rapidly star-forming offer very strong evidence that long gamma-ray bursts are associated with massive stars. The most widely accepted mechanism for the origin of long-duration GRBs is the collapsar model,[59] in which the core of an extremely massive, low-metallicity, rapidly rotating star collapses into a black hole in the final stages of its evolution. Matter near the star's core rains down towards the center and swirls into a high-density accretion disk. The infall of this material into a black hole drives a pair of relativistic jets out along the rotational axis, which pummel through the stellar envelope and eventually break through the stellar surface and radiate as gamma rays. Some alternative models replace the black hole with a newly formed magnetar,[60] although most other aspects of the model (the collapse of the core of a massive star and the formation of relativistic jets) are the same.
The closest analogs within the Milky Way galaxy of the stars producing long gamma-ray bursts are likely the Wolf–Rayet stars, extremely hot and massive stars which have shed most or all of their hydrogen due to radiation pressure. Eta Carinae and WR 104 have been cited as possible future gamma-ray burst progenitors.[61] It is unclear if any star in the Milky Way has the appropriate characteristics to produce a gamma-ray burst.[62]
The massive-star model probably does not explain all types of gamma-ray burst. There is strong evidence that some short-duration gamma-ray bursts occur in systems with no star formation and where no massive stars are present, such as elliptical galaxies and galaxy halos.[56] The favored theory for the origin of most short gamma-ray bursts is the merger of a binary system consisting of two neutron stars. According to this model, the two stars in a binary slowly spiral towards each other due to the release of energy via gravitational radiation[63][64] until the neutron stars suddenly rip each other apart due to tidal forces and collapse into a single black hole. The infall of matter into the new black hole produces an accretion disk and releases a burst of energy, analogous to the collapsar model. Numerous other models have also been proposed to explain short gamma-ray bursts, including the merger of a neutron star and a black hole, the accretion-induced collapse of a neutron star, or the evaporation of primordial black holes.[65][66][67][68]
Emission mechanisms
The means by which gamma-ray bursts convert energy into radiation remains poorly understood, and as of 2010 there was still no generally accepted model for how this process occurs.[69] Any successful model of GRB emission must explain the physical process for generating gamma-ray emission that matches the observed diversity of light-curves, spectra, and other characteristics.[70] Particularly challenging is the need to explain the very high efficiencies that are inferred from some explosions: some gamma-ray bursts may convert as much as half (or more) of the explosion energy into gamma-rays.[71] Recent observations of the bright optical counterpart of GRB 080319B, whose light curve was correlated with the gamma-ray light curve,[47] has suggested that inverse Compton may be the dominant process in some events. In this model, pre-existing low-energy photons are scattered by relativistic electrons within the explosion, augmenting their energy by a large factor and transforming them into gamma-rays.[72]
The nature of the longer-wavelength afterglow emission (ranging from X-ray through radio) that follows gamma-ray bursts is better understood. Any energy released by the explosion not radiated away in the burst itself takes the form of matter or energy moving outward at nearly the speed of light. As this matter collides with the surrounding interstellar gas, it creates a relativistic shock wave that then propagates forward into interstellar space. A second shock wave, the reverse shock, may propagate back into the ejected matter. Extremely energetic electrons within the shock wave are accelerated by strong local magnetic fields and radiate as synchrotron emission across most of the electromagnetic spectrum.[73][74] This model has generally been successful in modeling the behavior of many observed afterglows at late times (generally, hours to days after the explosion), although there are difficulties explaining all features of the afterglow very shortly after the gamma-ray burst has occurred.[75]
Rates and potential effects on earth life
All the bursts astronomers have recorded so far have come from distant galaxies and been harmless on the ground of earh, but if one occurred within our galaxy and if aimed straight at us, the effects could be devastating.Currently orbiting satellites detect an average of about one gamma-ray burst per day.
Measuring the exact rate is difficult, but for a galaxy of approximately the same size as the Milky Way, the expected rate (for long GRBs) is about one burst every 100,000 to 1,000,000 years.Only a small percentage of these would be beamed towards Earth. Estimates of rates of short GRBs are even more uncertain because of the unknown degree of collimation, but are probably comparable.
Gamma-ray bursts are thought to emerge mainly from the poles of a collapsing star. This creates two, oppositely shining beams of radiation shaped like narrow cones. Planets not lying in these cones would be comparatively safe; the chief worry is for those that do.
Potential effect comparing Deinococcus radiodurans
- The first is a flash of gamma rays. The flash can damage even the most radioactive resistant organisms known, the bacterium Deinococcus radiodurans. This bacteria can take 2000 times more radiation but prove to kill humans.
- For a planet with a thin atmosphere, the gamma flash could kill 90 percent of D.radiodurans from distances up to three times our galaxy’s width. A thick atmosphere would protect the microbes from this, but not necessarily from a second component of the beam, ultraviolet radiation[76].
- For thick atmosphere planets, a gamma-ray burst’s ultraviolet rays would kill 90 percent of D. radiodurans at distances ranging from 13,000 to 62,000 light years.
- If life survived that onslaught would have to contend with a third effect, depletion of the atmosphere’s protective ozone layer by the burst. This would kill 90 percent of D. radiodurans at up to 40 percent of the distance across the Milky Way[77].
Hypothetical effects of Gamma ray from past
GRBs close enough to affect life in some way might occur once every five million years or so - around a thousand times since life began[78].
Ordovician Mass Extinction 450 million years ago. The Earth’s second most devastating extinction is hypothetically caused by past GRB Pattern of extinctions in the late Ordovician species of trilobite that spent some of their lives in the plankton layer near the ocean surface were much harder hit than deep-water dwellers, which tended to stay put within quite restricted areas. Usually it is the more widely spread species that fare better in extinction says this unusual pattern could be explained by a GRB, which would probably devastate creatures living on land and near the ocean surface, but leave deep-sea creatures relatively unharmed[79][80].
Hypothetical effects of gamma ray burst in future
The real danger comes from the Wolf-Rayet stars regarded by astronomers as ticking bombs[81]. When it will change to supernova it may emmit intense beam of gamma ray, if earth comes to lie in the beam zone devastating effects may happen. Gamma rays would not penetrate Earth's atmosphere well to burn the ground, but they would chemically damage the stratosphere
If WR 104 were to hit earth with a burst 10 seconds or long, its gamma rays could deplete about 25 percent of the world's ozone layer.It would create mass extinction,starvation and food chain depletion. Earth side facing the GRB may face radiation exposure and humans on that side
will have radiation sickness cosmic rays coming from space to earth without ozone will be more space disasters[82].
Events after exposure to the gamma ray burst on earth's atmosphere
-
After effects of gamma ray burst
Most likely Earth may absorb and soak gamma rays but its energy may cause chemical reaction for oxygen and nitrogen molecules which may create nitrogen oxide then nitrogen dioxide gas causing photochemical smog. Burst may produce enough of the gas to cover sky and darken it. Gas will prevent sunlight to enter earth and even deplete rest of the ozone layer thus exposing whole of the earth to all types of cosmic radiation[83]
See also
- Gamma-ray astronomy
- List of gamma-ray bursts
- Stellar evolution
- Terrestrial gamma-ray flashes
- GRB 020813
Footnotes
- ^ A notable exception is the 5 March event of 1979, an extremely bright burst that was successfully localized to supernova remnant N49 in the Large Magellanic Cloud. This event is now interpreted as a magnetar giant flare, more related to SGR flares than "true" gamma-ray bursts.
- ^ GRBs are named after the date on which they are discovered: the first two digits being the year, followed by the two-digit month and two-digit day. If two or more GRBs occur on a given day, the letter 'A' is appended to the name for the first burst identified, 'B' for the second, and so on.
- ^ The duration of a burst is typically measured by T90, the duration of the period which 90 percent of the burst's energy is emitted. Recently some otherwise "short" GRBs have been shown to be followed by a second, much longer emission episode that when included in the burst light curve results in T90 durations of up to several minutes: these events are only short in the literal sense when this component is excluded.
Notes
- ^ Podsiadlowski 2004
- ^ Melott 2004
- ^ Hurley 2003
- ^ a b Schilling 2002, p.12–16
- ^ Klebesadel R.W., Strong I.B., and Olson R.A. (1973). "Observations of Gamma-Ray Bursts of Cosmic Origin". Astrophysical Journal Letters. 182: L85. Bibcode:1973ApJ...182L..85K. doi:10.1086/181225.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Meegan 1992
- ^ Schilling 2002, p.36–37
- ^ Paczyński 1999, p. 6
- ^ Piran 1992
- ^ Lamb 1995
- ^ Hurley 1986, p. 33
- ^ Pedersen 1987
- ^ Hurley 1992
- ^ a b Fishman & Meegan 1995
- ^ Paczynski 1993
- ^ van Paradijs 1997
- ^ Schilling 2002, p. 102
- ^ Reichart 1995
- ^ Schilling 2002, p. 118–123
- ^ a b Galama 1998
- ^ Ricker 2003
- ^ McCray 2008
- ^ Gehrels 2004
- ^ Akerlof 2003
- ^ Akerlof 1999
- ^ Katz 2002, p. 37
- ^ Marani 1997
- ^ Lazatti 2005
- ^ Simić 2005
- ^ Kouveliotou 1994
- ^ Horvath 1998
- ^ Hakkila 2003
- ^ Chattopadhyay 2007
- ^ Virgili 2009
- ^ Woosley & Bloom 2006
- ^ Pontzen et al 2010
- ^ Science Daily 2011
- ^ Levan 2011
- ^ Bloom 2011
- ^ Bloom 2006
- ^ Hjorth 2005
- ^ Berger 2007
- ^ Zhang 2009
- ^ Nakar 2007
- ^ Frederiks 2008
- ^ Hurley 2005
- ^ a b Racusin 2008
- ^ Bloom 2009
- ^ Rykoff 2009
- ^ Abdo 2009
- ^ Sari 1999
- ^ Burrows 2006
- ^ a b Frail 2001
- ^ Mazzali 2005
- ^ Frail 2000
- ^ a b Prochaska 2006
- ^ Watson 2006
- ^ Grupe 2006
- ^ MacFadyen 1999
- ^ Metzger 2007
- ^ Plait 2008
- ^ Stanek 2006
- ^ Abbott 2007
- ^ Kochanek 1993
- ^ Vietri 1998
- ^ MacFadyen 2006
- ^ Blinnikov 1984
- ^ Cline 1996
- ^ Stern 2007
- ^ Fishman, G. 1995
- ^ Fan & Piran 2006
- ^ Wozniak 2009
- ^ Meszaros 1997
- ^ Sari 1998
- ^ Nousek 2006
- ^ Galante and Horvath
- ^ http://www.world-science.net/exclusives/070226_grb-life.htm
- ^ New Scientist print edition, 15 December 2001, p 10). John Scalo and Craig Wheeler of the University of Texas at Austin
- ^ Adrian Melott of the University of Kansas in Lawrence
- ^ Bruce Lieberman, a specialist in fossil trilobites also at the University of Kansas, and other colleagues
- ^ Peter Tuthill, an astronomer at the University of Sydney
- ^ Adrian Melott of the University of Kansas in Lawrence
- ^ Adrian Melott of the University of Kansas in Lawrence
Books
- Vedrenne, G and Atteia, J.-L. (2009). Gamma-Ray Bursts: The brightest explosions in the Universe. Springer/Praxis Books. ISBN 978-3-540-39085-5.
{{cite book}}
: CS1 maint: multiple names: authors list (link)
References
- Abbott, B.; et al. (2007). "Search for Gravitational Waves Associated with 39 Gamma-Ray Bursts Using Data from the Second, Third, and Fourth LIGO Runs". Physical Review D. 77 (6): 062004. arXiv:0709.0766. Bibcode:2008PhRvD..77f2004A. doi:10.1103/PhysRevD.77.062004.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Abdo, A.A.; et al. (2009). "Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C". Science. 323 (5922): 1688–93. Bibcode:2009Sci...323.1688A. doi:10.1126/science.1169101. PMID 19228997.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Akerlof, C.; et al. (1999). "Observation of contemporaneous optical radiation from a gamma-ray burst". Nature. 398 (3): 400–402. arXiv:astro-ph/9903271. Bibcode:1999Natur.398..400A. doi:10.1038/18837. PMID 18837.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Akerlof, C.; et al. (2003). "The ROTSE-III Robotic Telescope System". Publications of the Astronomical Society of the Pacific. 115: 132–140. arXiv:astro-ph/0210238. Bibcode:2003PASP..115..132A. doi:10.1086/345490.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Atwood, W.B. (2009). "The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission". arXiv:0902.1089 [astro-ph].
{{cite arXiv}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - Barthelmy, S.D.; et al. (2005). "The Burst Alert Telescope (BAT) on the SWIFT Midex Mission". Space Science Reviews. 120 (3–4): 143–164. arXiv:astro-ph/0507410. Bibcode:2005SSRv..120..143B. doi:10.1007/s11214-005-5096-3.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Berger, E.; et al. (2007). "Galaxy Clusters Associated with Short GRBs. I. The Fields of GRBs 050709, 050724, 050911, and 051221a". Astrophysical Journal. 660: 496–503. arXiv:astro-ph/0608498. Bibcode:2007ApJ...660..496B. doi:10.1086/512664.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Blinnikov, S.; et al. (1984). "Exploding Neutron Stars in Close Binaries". Soviet Astronomy Letters. 10: 177. Bibcode:1984SvAL...10..177B.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Bloom, J.S.; et al. (2006). "Closing in on a Short-Hard Burst Progenitor: Constraints from Early-Time Optical Imaging and Spectroscopy of a Possible Host Galaxy of GRB 050509b". Astrophysical Journal. 638: 354–368. arXiv:astro-ph/0505480. Bibcode:2006ApJ...638..354B. doi:10.1086/498107.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Bloom, J.S.; et al. (2009). "Observations of the Naked-Eye GRB 080319B: Implications of Nature's Brightest Explosion". Astrophysical Journal. 691: 723–737. Bibcode:2009ApJ...691..723B. doi:10.1088/0004-637X/691/1/723.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Bloom, J. S. (2011-06-16). "A Possible Relativistic Jetted Outburst from a Massive Black Hole Fed by a Tidally Disrupted Star". Science. 332. doi:10.1126/science.1207150. Retrieved 2011-06-19.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - Burrows, D.N.; et al. (2006). "Jet Breaks in Short Gamma-Ray Bursts. II. The Collimated Afterglow of GRB 051221A". Astrophysical Journal. 653: 468–473. arXiv:astro-ph/0604320. Bibcode:2006ApJ...653..468B. doi:10.1086/508740.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Cline, D.B. (1996). "Primordial black-hole evaporation and the quark-gluon phase transition". Nuclear Physics A. 610: 500. Bibcode:1996NuPhA.610..500C. doi:10.1016/S0375-9474(96)00383-1.
- Chattopadhyay, T.; et al. (2007). "Statistical Evidence for Three Classes of Gamma-Ray Bursts". Astrophysical Journal. 667: 1017. Bibcode:2007ApJ...667.1017C. doi:10.1086/520317.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Ejzak, L.M.; et al. (2007). "Terrestrial Consequences of Spectral and Temporal Variability in Ionizing Photon Events". Astrophysical Journal. 654: 373–384. arXiv:astro-ph/0604556. Bibcode:2007ApJ...654..373E. doi:10.1086/509106.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Fan, Y. and Piran, T. (2006). "Gamma-ray burst efficiency and possible physical processes shaping the early afterglow". Monthly Notices of the Royal Astronomical Society. 369: 197–206. arXiv:astro-ph/0601054. Bibcode:2006MNRAS.369..197F. doi:10.1111/j.1365-2966.2006.10280.x.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Fishman, C.J. and Meegan, C.A. (1995). "Gamma-Ray Bursts". Annual Review of Astronomy and Astrophysics. 33: 415–458. Bibcode:1995ARA&A..33..415F. doi:10.1146/annurev.aa.33.090195.002215.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Fishman, G.J. (1995). "Gamma-Ray Bursts: An Overview". NASA. Retrieved 2007-10-12.
- Frail, D.A.; et al. (2001). "Beaming in Gamma-Ray Bursts: Evidence for a Standard Energy Reservoir". Astrophysical Journal Letters. 562: L557–L558. arXiv:astro-ph/0102282. Bibcode:2001ApJ...562L..55F. doi:10.1086/338119.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Frail, D.A.; et al. (2000). "A 450 Day Light Curve of the Radio Afterglow of GRB 970508: Fireball Calorimetry". Astrophysical Journal. 537 (7): 191–204. arXiv:astro-ph/9910319. Bibcode:2000ApJ...537..191F. doi:10.1086/309024. PMID 309024.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Frederiks, D.; et al. (2008). "GRB 051103 and GRB 070201 as Giant Flares from SGRs in Nearby Galaxies". In Galassi, Palmer, and Fenimore (ed.). American Institute of Physics Conference Series. Vol. 1000. pp. 271–275. Bibcode:2008AIPC.1000..271F. doi:10.1063/1.2943461.
{{cite conference}}
: Explicit use of et al. in:|author=
(help); Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: editors list (link) - Frontera, F. and Piro, L. (1998). Proceedings of Gamma-Ray Bursts in the Afterglow Era. Astronomy and Astrophysics Supplement Series.
{{cite book}}
: CS1 maint: multiple names: authors list (link) - Galama, T.J.; et al. (1998). "An unusual supernova in the error box of the gamma-ray burst of 25 April 1998". Nature. 395 (1): 670–672. arXiv:astro-ph/9806175. Bibcode:1998Natur.395..670G. doi:10.1038/27150. PMID 27150.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Garner, R. (2008). "NASA's Swift Catches Farthest Ever Gamma-Ray Burst". NASA. Retrieved 2008-11-03.
- Gehrels, N.; et al. (2004). "The Swift Gamma-Ray Burst Mission". Astrophysical Journal. 611: 1005–1020. Bibcode:2004ApJ...611.1005G. doi:10.1086/422091.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Gehrels, N.; et al. (2005). "A short gamma-ray burst apparently associated with an elliptical galaxy at redshift z=0.225". Nature. 437 (7060): 851–854. arXiv:astro-ph/0505630. Bibcode:2005Natur.437..851G. doi:10.1038/nature04142. PMID 16208363.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Grupe, D.; et al. (2006). "Jet Breaks in Short Gamma-Ray Bursts. I: The Uncollimated Afterglow of GRB 050724". Astrophysical Journal. 653: 462. arXiv:astro-ph/0603773. Bibcode:2006ApJ...653..462G. doi:10.1086/508739.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Guetta, D. and Piran, T. (2006). "The BATSE-Swift luminosity and redshift distributions of short-duration GRBs". Astronomy and Astrophysics. 453: 823–828. arXiv:astro-ph/0511239. Bibcode:2006A&A...453..823G. doi:10.1051/0004-6361:20054498.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Hakkila, J.; et al. (2003). "How Sample Completeness Affects Gamma-Ray Burst Classification". Astrophysical Journal. 582: 320. arXiv:astro-ph/0209073. Bibcode:2003ApJ...582..320H. doi:10.1086/344568.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Horvath, I. (1998). "A Third Class of Gamma-Ray Bursts?". Astrophysical Journal. 508: 757. arXiv:astro-ph/9803077. Bibcode:1998ApJ...508..757H. doi:10.1086/306416.
- Hjorth, J.; et al. (2005). "GRB 050509B: Constraints on Short Gamma-Ray Burst Models". Astrophysical Journal Letters. 630 (2): L117–L120. arXiv:astro-ph/0506123. Bibcode:2005ApJ...630L.117H. doi:10.1086/491733.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Hurley, K., Cline, T. and Epstein, R. (1986). "Error Boxes and Spatial Distribution". In Liang, E.P. and Petrosian, V. (ed.). AIP Conference Proceedings. Gamma-Ray Bursts. Vol. 141. American Institute of Physics. pp. 33–38. ISBN 0-88318-340-4.
{{cite conference}}
: Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: authors list (link) - Hurley, K. (1992). "Gamma-Ray Bursts – Receding from Our Grasp". Nature. 357 (6374): 112. Bibcode:1992Natur.357..112H. doi:10.1038/357112a0.
- Hurley, K. (2003). "A Gamma-Ray Burst Bibliography, 1973–2001" (PDF). In Ricker, G.R. and Vanderspek, R.K. (ed.). Gamma-Ray Burst and Afterglow Astronomy, 2001: A Workshop Celebrating the First Year of the HETE Mission. American Institute of Physics. pp. 153–155. ISBN 0-7354-0122-5.
{{cite conference}}
: Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: editors list (link) - Hurley, K.; et al. (2005). "An exceptionally bright flare from SGR 1806-20 and the origins of short-duration gamma-ray bursts". Nature. 434 (7037): 1098–1103. arXiv:astro-ph/0502329. Bibcode:2005Natur.434.1098H. doi:10.1038/nature03519. PMID 15858565.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Katz, J.I. (2002). The Biggest Bangs. Oxford University Press. ISBN 0-19-514570-4.
- Klebesadel, R.; et al. (1973). "Observations of Gamma-Ray Bursts of Cosmic Origin". Astrophysical Journal Letters. 182: L85. Bibcode:1973ApJ...182L..85K. doi:10.1086/181225.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Kochanek, C.S. and Piran, T. (1993). "Gravitational Waves and gamma -Ray Bursts". Astrophysical Journal Letters. 417: L17–L23. arXiv:astro-ph/9305015. Bibcode:1993ApJ...417L..17K. doi:10.1086/187083.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Kouveliotou, C.; et al. (1993). "Identification of two classes of gamma-ray bursts". Astrophysical Journal Letters. 413: L101. Bibcode:1993ApJ...413L.101K. doi:10.1086/186969.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Lamb, D.Q. (1995). "The Distance Scale to Gamma-Ray Bursts". Publications of the Astronomical Society of the Pacific. 107: 1152. Bibcode:1995PASP..107.1152L. doi:10.1086/133673.
- Lazzati, D. (2005). "Precursor activity in bright, long BATSE gamma-ray bursts". Monthly Notices of the Royal Astronomical Society. 357: 722–731. arXiv:astro-ph/0411753. Bibcode:2005MNRAS.357..722L. doi:10.1111/j.1365-2966.2005.08687.x.
- Levan, A. J. (2011-06-16). "An Extremely Luminous Panchromatic Outburst from the Nucleus of a Distant Galaxy". Science. 332. doi:10.1126/science.1207143. Retrieved 2011-06-19.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - MacFadyen, A.I. and Woosley, S. (1999). "Collapsars: Gamma-Ray Bursts and Explosions in "Failed Supernovae"". Astrophysical Journal. 524: 262–289. arXiv:astro-ph/9810274. Bibcode:1999ApJ...524..262M. doi:10.1086/307790.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - MacFadyen, A.I. (2006). "Late flares from GRBs — Clues about the Central Engine". AIP Conference Proceedings. 836: 48–53. Bibcode:2006AIPC..836...48M. doi:10.1063/1.2207856.
- Marani, G.F.; et al. (1997). "On Similarities among GRBs". Bulletin of the American Astronomical Society. 29: 839. Bibcode:1997AAS...190.4311M.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Mazzali, P.A.; et al. (2005). "An Asymmetric Energetic Type Ic Supernova Viewed Off-Axis, and a Link to Gamma Ray Bursts". Science. 308 (5726): 1284–1287. arXiv:astro-ph/0505199. Bibcode:2005Sci...308.1284M. doi:10.1126/science.1111384. PMID 15919986.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Meegan, C.A.; et al. (1992). "Spatial distribution of gamma-ray bursts observed by BATSE". Nature. 355 (6356): 143. Bibcode:1992Natur.355..143M. doi:10.1038/355143a0.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Melott, A.L.; et al. (2004). "Did a gamma-ray burst initiate the late Ordovician mass extinction?". International Journal of Astrobiology. 3: 55–61. arXiv:astro-ph/0309415. Bibcode:2004IJAsB...3...55M. doi:10.1017/S1473550404001910.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Meszaros, P. and Rees, M.J. (1997). "Optical and Long-Wavelength Afterglow from Gamma-Ray Bursts". Astrophysical Journal. 476: 232. arXiv:astro-ph/9606043. Bibcode:1997ApJ...476..232M. doi:10.1086/303625.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Metzger, B.; et al. (2007). Proto-Neutron Star Winds, Magnetar Birth, and Gamma-Ray Bursts. Vol. 937. pp. 521–525. Bibcode:2007AIPC..937..521M. doi:10.1063/1.2803618.
{{cite conference}}
: Explicit use of et al. in:|author=
(help); Unknown parameter|book title=
ignored (help) - Mukherjee, S.; et al. (1998). "Three Types of Gamma-Ray Bursts". Astrophysical Journal. 508: 314. arXiv:astro-ph/9802085. Bibcode:1998ApJ...508..314M. doi:10.1086/306386.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Nakar, E. (2007). "Short-hard gamma-ray bursts". Physics Reports. 442: 166–236. arXiv:astro-ph/0701748. Bibcode:2007PhR...442..166N. doi:10.1016/j.physrep.2007.02.005.
- McCray, Richard; et al. "Report of the 2008 Senior Review of the Astrophysics Division Operating Missions" (PDF).
{{cite web}}
: Explicit use of et al. in:|author=
(help) - "Very Large Array Detects Radio Emission From Gamma-Ray Burst" (Press release). National Radio Astronomy Observatory. 15 May 1997. Retrieved 2009-04-04.
- Nousek, J.A.; et al. (2006). "Evidence for a Canonical Gamma-Ray Burst Afterglow Light Curve in the Swift XRT Data". Astrophysical Journal. 642: 389–400. arXiv:astro-ph/0508332. Bibcode:2006ApJ...642..389N. doi:10.1086/500724.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Paczyński, B. and Rhoads, J.E. (1993). "Radio Transients from Gamma-Ray Bursters". Astrophysics Journal. 418: 5. arXiv:astro-ph/9307024. Bibcode:1993ApJ...418L...5P. doi:10.1086/187102.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Paczyński, B. (1995). "How Far Away Are Gamma-Ray Bursters?". Publications of the Astronomical Society of the Pacific. 107: 1167. arXiv:astro-ph/9505096. Bibcode:1995PASP..107.1167P. doi:10.1086/133674.
- Paczyński, B. (1999). "Gamma-Ray Burst–Supernova relation". In M. Livio, N. Panagia, K. Sahu (ed.). Supernovae and Gamma-Ray Bursts: The Greatest Explosions Since the Big Bang. Space Telescope Science Institute. pp. 1–8. ISBN 0-521-79141-3.
{{cite conference}}
: Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: editors list (link) - Pedersen, H.; et al. (1986). "Deep Searches for Burster Counterparts". In Liang, Edison P.; Petrosian, Vahé (ed.). AIP Conference Proceedings. Gamma-Ray Bursts. Vol. 141. American Institute of Physics. pp. 39–46. ISBN 0-88318-340-4.
{{cite conference}}
: Explicit use of et al. in:|author=
(help); Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: editors list (link) - Plait, Phil (2 March 2008). "WR 104: A nearby gamma-ray burst?". Bad Astronomy. Retrieved 2009-01-07.
- Piran, T. (1992). "The implications of the Compton (GRO) observations for cosmological gamma-ray bursts". Astrophysical Journal Letters. 389: L45. Bibcode:1992ApJ...389L..45P. doi:10.1086/186345.
- Piran, T. (1997). "Toward understanding gamma-ray bursts". In Bahcall, J.N. and Ostriker, J. (ed.). Unsolved Problems in Astrophysics. p. 343. Bibcode:1997upa..conf..343P.
{{cite conference}}
: Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: editors list (link) - Podsiadlowski, Ph.; et al. (2004). "The Rates of Hypernovae and Gamma-Ray Bursts: Implications for Their Progenitors". Astrophysical Journal Letters. 607: L17. arXiv:astro-ph/0403399. Bibcode:2004ApJ...607L..17P. doi:10.1086/421347.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Pontzen, A.; et al. (2010). "The nature of HI absorbers in GRB afterglows: clues from hydrodynamic simulations". MNRAS. 402: 1523. Bibcode:2010MNRAS.402.1523P. doi:10.1111/j.1365-2966.2009.16017.x.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Prochaska, J.X.; et al. (2006). "The Galaxy Hosts and Large-Scale Environments of Short-Hard Gamma-Ray Bursts". Astrophysical Journal. 641: 989. arXiv:astro-ph/0510022. Bibcode:2006ApJ...642..989P. doi:10.1086/501160.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Racusin, J.L.; et al. (2008). "Broadband observations of the naked-eye gamma-ray burst GRB080319B". Nature. 455 (7210): 183–188. Bibcode:2008Natur.455..183R. doi:10.1038/nature07270. PMID 18784718.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Reddy, F. (28 April 2009). "New Gamma-Ray Burst Smashes Cosmic Distance Record" (Press release). NASA. Retrieved 2009-05-16.
- Ricker, G.R. and Vanderspek, R.K. (2003). "The High Energy Transient Explorer (HETE): Mission and Science Overview". In Ricker, G.R. and Vanderspek, R.K. (ed.). Gamma-Ray Burst and Afterglow Astronomy 2001: A Workshop Celebrating the First Year of the HETE Mission. American Institute of Physics Conference Series. Vol. 662. pp. 3–16. Bibcode:2003AIPC..662....3R. doi:10.1063/1.1579291.
{{cite conference}}
: Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: authors list (link) - Reichart, Daniel E. (1998). "The Redshift of GRB 970508". Astrophysical Journal Letters. 495: L99. arXiv:astro-ph/9712100. Bibcode:1998ApJ...495L..99R. doi:10.1086/311222.
- Rykoff, E.; et al. (2009). "Looking Into the Fireball: ROTSE-III and Swift Observations of Early GRB Afterglows". Astrophysical Journal. 702: 489. arXiv:0904.0261. Bibcode:2009ApJ...702..489R. doi:10.1088/0004-637X/702/1/489.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Polak, L.; Piran, T; Narayan, R (1998). "Spectra and Light Curves of Gamma-Ray Burst Afterglows". Astrophysical Journal Letters. 497 (5): L17. arXiv:astro-ph/9712005. Bibcode:1998ApJ...497L..17S. doi:10.1086/311269. PMID 311269.
{{cite journal}}
: More than one of|author1=
and|author=
specified (help) - Sari, R; Piran, T; Halpern, J.P (1999). "Jets in Gamma-Ray Bursts". Astrophysical Journal Letters. 519: L17–L20. arXiv:astro-ph/9903339. Bibcode:1999ApJ...519L..17S. doi:10.1086/312109.
- Schilling, Govert (2002). Flash! The hunt for the biggest explosions in the universe. Cambridge University Press. ISBN 0-521-80053-6.
- "Gamma-Ray Flash Came from Star Being Eaten by Massive Black Hole". Science Daily web site. ScienceDaily LLC. 2011-06-16. Retrieved 2011-06-19.
{{cite web}}
: Cite has empty unknown parameter:|coauthors=
(help); External link in
(help)|work=
- Simić, S.; et al. (2005). "A model for temporal variability of the GRB light curve". In Bulik, T., Rudak, B, and Madejski, G. (ed.). Astrophysical Sources of High Energy Particles and Radiation. American Institute of Physics Conference Series. Vol. 801. pp. 139–140. Bibcode:2005AIPC..801..139S. doi:10.1063/1.2141849.
{{cite conference}}
: Explicit use of et al. in:|author=
(help); Unknown parameter|booktitle=
ignored (|book-title=
suggested) (help)CS1 maint: multiple names: editors list (link) - Stanek, K.Z.; et al. (2006). "Protecting Life in the Milky Way: Metals Keep the GRBs Away" (PDF). Acta Astronomica. arXiv:astro-ph/0604113. Bibcode:2006AcA....56..333S.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Stern, Boris E. and Poutanen, Juri (2004). "Gamma-ray bursts from synchrotron self-Compton emission". Monthly Notices of the Royal Astronomical Society. 352 (3): L35–L39. arXiv:astro-ph/0405488. Bibcode:2004MNRAS.352L..35S. doi:10.1111/j.1365-2966.2004.08163.x.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Thorsett, S.E. (1995). "Terrestrial implications of cosmological gamma-ray burst models". Astrophysical Journal Letters. 444: L53. arXiv:astro-ph/9501019. Bibcode:1995ApJ...444L..53T. doi:10.1086/187858.
- "TNG caught the farthest GRB observed ever". Fundación Galileo Galilei. 24 April 2009. Retrieved 2009-04-25.
- van Paradijs, J.; et al. (1997). "Transient optical emission from the error box of the gamma-ray burst of 28 February 1997". Nature. 386 (6626): 686. Bibcode:1997Natur.386..686V. doi:10.1038/386686a0.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Vietri, M. and Stella, L. (1998). "A Gamma-Ray Burst Model with Small Baryon Contamination". Astrophysical Journal Letters. 507: L45–L48. arXiv:astro-ph/9808355. Bibcode:1998ApJ...507L..45V. doi:10.1086/311674.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Virgili, F.J., Liang, E.-W. and Zhang, B. (2009). "Low-luminosity gamma-ray bursts as a distinct GRB population: a firmer case from multiple criteria constraints". Monthly Notices of the Royal Astronomical Society. 392: 91–103. Bibcode:2009MNRAS.392...91V. doi:10.1111/j.1365-2966.2008.14063.x.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Wanjek, Christopher (4 June 2005). "Explosions in Space May Have Initiated Ancient Extinction on Earth". NASA. Retrieved 2007-09-15.
- Watson, D.; et al. (2006). "Are short γ-ray bursts collimated? GRB 050709, a flare but no break". Astronomy and Astrophysics. 454: L123–L126. arXiv:astro-ph/0604153. Bibcode:2006A&A...454L.123W. doi:10.1051/0004-6361:20065380.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - Woosley, S.E. and Bloom, J.S. (2006). "The Supernova Gamma-Ray Burst Connection". Annual Review of Astronomy and Astrophysics. 44: 507–556. arXiv:astro-ph/0609142. Bibcode:2006ARA&A..44..507W. doi:10.1146/annurev.astro.43.072103.150558.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Wozniak, P.R.; et al. (2009). "Gamma-Ray Burst at the Extreme: The Naked-Eye Burst GRB 080319B". Astrophysical Journal. 691: 495–502. Bibcode:2009ApJ...691..495W. doi:10.1088/0004-637X/691/1/495.
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: Explicit use of et al. in:|author=
(help) - Zhang, B. (2009-10-01). "Discerning the physical origins of cosmological gamma-ray bursts based on multiple observational criteria: the cases of z = 6.7 GRB 080913, z = 8.2 GRB 090423, and some short/hard GRBs". Astrophysical Journal. 703 (2): 1696–1724. doi:10.1088/0004-637X/703/2/1696. Retrieved 2011-06-19.
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External links
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/40px-Wiktionary-logo-en-v2.svg.png)
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- GRB Mission Sites
- Swift Gamma-Ray Burst Mission:
- HETE-2: High Energy Transient Explorer (Wiki entry)
- INTEGRAL: INTErnational Gamma-Ray Astrophysics Laboratory (Wiki entry)
- BATSE: Burst and Transient Source Explorer
- Fermi Gamma-ray Space Telescope (Wiki entry)
- AGILE: Astro-rivelatore Gamma a Immagini Leggero (Wiki entry)
- EXIST: Energetic X-ray Survey Telescope
- GRB Follow-up Programs
- The Gamma-ray bursts Coordinates Network (GCN) (Wiki entry)
- GROND: Gamma-Ray Burst Optical Near-infrared Detector (Wiki entry)
- PROMPT: Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (Wiki entry)
- RAPTOR: Rapid Telescopes for Optical Response
- ROTSE: Robotic Optical Transient Search Experiment (Wiki entry)
- PAIRITEL: Peters Automated Infrared Imaging Telescope
- MASTER: Mobile Astronomical System of the Telescope-Robots
- KAIT: The Katzman Automatic Imaging Telescope (Wiki entry)
- REM: Rapid Eye Mount