In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies, described by NASA as "the most powerful class of explosions in the universe". They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milliseconds to several hours. After an initial flash of gamma rays, a longer-lived "afterglow" is usually emitted at longer wavelengths.
A super-luminous supernova is a type of stellar explosion with a luminosity 10 or more times higher than that of standard supernovae. Like supernovae, SLSNe seem to be produced by several mechanisms, which is readily revealed by their light-curves and spectra. There are multiple models for what conditions may produce an SLSN, including core collapse in particularly massive stars, millisecond magnetars, interaction with circumstellar material, or pair-instability supernovae.
The Fermi Gamma-ray Space Telescope, formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is the Large Area Telescope (LAT), with which astronomers mostly intend to perform an all-sky survey studying astrophysical and cosmological phenomena such as active galactic nuclei, pulsars, other high-energy sources and dark matter. Another instrument aboard Fermi, the Gamma-ray Burst Monitor, is being used to study gamma-ray bursts and solar flares.
GRB 970228 was the first gamma-ray burst (GRB) for which an afterglow was observed. It was detected on 28 February 1997 at 02:58 UTC. Since 1993, physicists had predicted GRBs to be followed by a lower-energy afterglow, but until this event, GRBs had only been observed in highly luminous bursts of high-energy gamma rays ; this resulted in large positional uncertainties which left their nature very unclear.
Nial Rahil Tanvir is a British astronomer at the University of Leicester. His research specialisms are the Extragalactic distance scale, Galaxy evolution and Gamma ray bursts. Tanvir has featured in various TV programs, including The Sky at Night hosted by Sir Patrick Moore, and Horizon
The Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) is an imaging instrument used to investigate Gamma-Ray Burst afterglows and for doing follow-up observations on exoplanets using transit photometry. It is operated at the 2.2-metre MPG/ESO telescope at ESO's La Silla Observatory in the southern part of the Atacama desert, about 600 kilometres north of Santiago de Chile and at an altitude of 2,400 metres.
GRB 970508 was a gamma-ray burst (GRB) detected on May 8, 1997, at 21:42 UTC; it is historically important as the second GRB with a detected afterglow at other wavelengths, the first to have a direct redshift measurement of the afterglow, and the first to be detected at radio wavelengths.
The history of gamma-ray began with the serendipitous detection of a gamma-ray burst (GRB) on July 2, 1967, by the U.S. Vela satellites. After these satellites detected fifteen other GRBs, Ray Klebesadel of the Los Alamos National Laboratory published the first paper on the subject, Observations of Gamma-Ray Bursts of Cosmic Origin. As more and more research was done on these mysterious events, hundreds of models were developed in an attempt to explain their origins.
GRB 051221A was a gamma ray burst (GRB) that was detected by NASA's Swift Gamma-Ray Burst Mission on December 21, 2005. A gamma-ray burst is a highly luminous flash of gamma rays, the most energetic form of electromagnetic radiation. The coordinates of the burst were α=21h 54m 50.7s, δ=16° 53′ 31.9″, and it lasted about 1.4 seconds. The same satellite discovered X-ray emission from the same object, and the GMOS Instrument on the Gemini Observatory discovered an afterglow in the visible spectrum. This was observed for the next ten days, allowing a redshift of Z = 0.5464 to be determined for the host galaxy.
GRB 090423 was a gamma-ray burst (GRB) detected by the Swift Gamma-Ray Burst Mission on April 23, 2009, at 07:55:19 UTC whose afterglow was detected in the infrared and enabled astronomers to determine that its redshift is z = 8.2, making it one of the most distant objects detected at that time with a spectroscopic redshift.
GRB 011211 was a gamma-ray burst (GRB) detected on December 11, 2001. A gamma-ray burst is a highly luminous flash associated with an explosion in a distant galaxy and producing gamma rays, the most energetic form of electromagnetic radiation, and often followed by a longer-lived "afterglow" emitted at longer wavelengths.
GRB 070714B was a gamma-ray burst (GRB) that was detected on 14 July 2007 at 04:59 UTC. A gamma-ray burst is a highly luminous flash associated with an explosion in a distant galaxy and producing gamma rays, the most energetic form of electromagnetic radiation, and often followed by a longer-lived "afterglow" emitted at longer wavelengths.
GRB 090429B was a gamma-ray burst observed on 29 April 2009 by the Burst Alert Telescope aboard the Swift satellite. The burst triggered a standard burst-response observation sequence, which started 106 seconds after the burst. The X-ray telescope aboard the satellite identified an uncatalogued fading source. No optical or UV counterpart was seen in the UV–optical telescope. Around 2.5 hours after the burst trigger, a series of observations was carried out by the Gemini North telescope, which detected a bright object in the infrared part of the spectrum. No evidence of a host galaxy was found either by Gemini North or by the Hubble Space Telescope. Though this burst was detected in 2009, it was not until May 2011 that its distance estimate of 13.14 billion light-years was announced. With 90% likelihood, the burst had a photometric redshift greater than z = 9.06, which would make it the most distant GRB known, although the error bar on this estimate is large, providing a lower limit of z > 7.
GRB 101225A, also known as the "Christmas burst", was a cosmic explosion first detected by NASA's Swift observatory on Christmas Day 2010. The gamma-ray emission lasted at least 28 minutes, which is unusually long. Follow-up observations of the burst's afterglow by the Hubble Space Telescope and ground-based observatories were unable to determine the object's distance using spectroscopic methods.
GRB 111209A is the longest lasting gamma-ray burst (GRB) detected by the Swift Gamma-Ray Burst Mission, observed on December 9, 2011. Its duration is longer than 7 hours, implying this event has a different kind of progenitor than normal long GRBs. It was first proposed that the progenitor of this event was a blue supergiant star with low metallicity. Later, it was also proposed that this event is the prototype of a new class of GRBs, ultra-long GRBs.
A hypernova is a very energetic supernova which is believed to result from an extreme core-collapse scenario. In this case, a massive star collapses to form a rotating black hole emitting twin astrophysical jets and surrounded by an accretion disk. It is a type of stellar explosion that ejects material with an unusually high kinetic energy, an order of magnitude higher than most supernovae, with a luminosity at least 10 times greater. Hypernovae release so much of gamma rays they usually appear similar to a type Ic supernova, but with unusually broad spectral lines indicating an extremely high expansion velocity. Hypernovae are one of the mechanisms for producing long gamma ray bursts (GRBs), which range from 2 seconds to over a minute in duration. They have also been referred to as superluminous supernovae, though that classification also includes other types of extremely luminous stellar explosions that have different origins.
NGC 4993 is a lenticular galaxy located about 140 million light-years away in the constellation Hydra. It was discovered on 26 March 1789 by William Herschel and is a member of the NGC 4993 Group.
GRB 190114C was an extreme gamma-ray burst explosion from a galaxy 4.5 billion light years away (z=0.4245; magnitude=15.60est) near the Fornax constellation, that was initially detected in January 2019. The afterglow light emitted soon after the burst was found to be tera-electron volt radiation from inverse Compton emission, identified for the first time. According to the astronomers, "We observed a huge range of frequencies in the electromagnetic radiation afterglow of GRB 190114C. It is the most extensive to date for a gamma-ray burst." Also, according to other astronomers, "light detected from the object had the highest energy ever observed for a GRB: 1 Tera electron volt (TeV) -- about one trillion times as much energy per photon as visible light"; another source stated, "the brightest light ever seen from Earth [to date].".
GRB 221009A also known as Swift J1913.1+1946 was an extraordinarily bright and long-lasting gamma-ray burst (GRB) jointly discovered by the Neil Gehrels Swift Observatory and the Fermi Gamma-ray Space Telescope on October 9, 2022. The gamma-ray burst was around seven minutes long, but was detectable for more than ten hours following initial detection. Despite being around two billion light-years away, it was powerful enough to affect Earth's atmosphere, having the strongest effect ever recorded by a gamma-ray burst on the planet. The peak luminosity of GRB 221009A was measured by Konus-Wind to be ~ 2.1 × 1047 J/s and by Fermi Gamma-ray Burst Monitor to be ~ 1.0 × 1047 J/s over the 1.024s interval. A burst as energetic and as close to Earth as 221009A is thought to be a once-in-10,000-year event. It was the brightest and most energetic gamma-ray burst ever recorded, with some dubbing it the "BOAT", or Brightest Of All Time.
