Information about Compton Gamma Ray Observatory
Gamma-ray astronomy is the astronomical study of the cosmos with gamma rays.
Gamma-rays coming from space are mostly absorbed by the Earth's atmosphere. So gamma-ray astronomy could not develop until it was possible to get our detectors above all or most of the atmosphere, using balloons or spacecraft. The first gamma-ray telescope carried into orbit, on the Explorer-XI satellite in 1961, picked up fewer than 100 cosmic gamma-ray photons. These appeared to come from all directions in the Universe, implying some sort of uniform "gamma-ray background". Such a background would be expected from the interaction of cosmic rays (very energetic charged particles in space) with gas found between the stars.
The first true astrophysical gamma-ray sources were solar flares, which revealed the strong 2.223 MeV line predicted by Morrison. This line results from the formation of deuterium via the union of a neutron and proton; in a solar flare the neutrons appear as secondaries from interactions of high-energy ions accelerated in the flare process. These first gamma-ray line observations were from OSO-3, OSO-7, and the Solar Maximum Mission, the latter spacecraft launched in 1980. The solar observations inspired theoretical work by Reuven Ramaty and others.
Significant gamma-ray emission from our galaxy was first detected in 1967 by the gamma-ray detector aboard the OSO-3 satellite. It detected 621 events attributable to cosmic gamma-rays. However, the field of gamma-ray astronomy took great leaps forward with the SAS-2 (1972) and the COS-B (1975-1982) satellites. These two satellites provided an exciting view into the high-energy universe (sometimes called the 'violent' universe, because the kinds of events in space that produce gamma-rays tend to be explosions, high-speed collisions, and such). They confirmed the earlier findings of the gamma-ray background, produced the first detailed map of the sky at gamma-ray wavelengths, and detected a number of point sources. However, the poor resolution of the instruments made it impossible to identify most of these point sources with individual stars or stellar systems.
Currently, the main space-based gamma ray observatory is the INTErnational Gamma-Ray Astrophysics Laboratory, (INTEGRAL). INTEGRAL is an ESA mission with contributions from Czech, Poland, USA and Russia. It was launched on 17 October 2002.
Very energetic gamma-rays can also be detected by ground based experiments. The Imaging Atmospheric Cherenkov Telescope technique currently achieves the highest sensitivity. The Crab Nebula, a steady source of so called TeV gamma-rays was first detected in 1989 by the Whipple Observatory (Az, USA). Modern Cherenkov telescope experiments like H.E.S.S., VERITAS, MAGIC, and CANGAROO III can detect the Crab Nebula in a few minutes. The most energetic photons (up to 16 TeV) observed from an extragalactic object originate from the blazar Markarian 501 (Mrk 501). These measurements were done by the High-Energy-Gamma-Ray Astronomy (HEGRA) air Cherenkov telescopes.
Gamma-ray astronomy is mostly dominated by the number of photons that can be detected. Larger area detectors and better background suppression are essential for progress in the field.
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Early history
Long before experiments could detect gamma rays emitted by cosmic sources, scientists had known that the universe should be producing these photons. Work by Feenberg and Primakoff in 1948, Hayakawa and Hutchinson in 1952, and, especially, Morrison in 1958 had led scientists to believe that a number of different processes which were occurring in the universe would result in gamma-ray emission. These processes included cosmic ray interactions with interstellar gas, supernova explosions, and interactions of energetic electrons with magnetic fields. However, it was not until the 1960s that our ability to actually detect these emissions came to pass.Gamma-rays coming from space are mostly absorbed by the Earth's atmosphere. So gamma-ray astronomy could not develop until it was possible to get our detectors above all or most of the atmosphere, using balloons or spacecraft. The first gamma-ray telescope carried into orbit, on the Explorer-XI satellite in 1961, picked up fewer than 100 cosmic gamma-ray photons. These appeared to come from all directions in the Universe, implying some sort of uniform "gamma-ray background". Such a background would be expected from the interaction of cosmic rays (very energetic charged particles in space) with gas found between the stars.
The first true astrophysical gamma-ray sources were solar flares, which revealed the strong 2.223 MeV line predicted by Morrison. This line results from the formation of deuterium via the union of a neutron and proton; in a solar flare the neutrons appear as secondaries from interactions of high-energy ions accelerated in the flare process. These first gamma-ray line observations were from OSO-3, OSO-7, and the Solar Maximum Mission, the latter spacecraft launched in 1980. The solar observations inspired theoretical work by Reuven Ramaty and others.
Significant gamma-ray emission from our galaxy was first detected in 1967 by the gamma-ray detector aboard the OSO-3 satellite. It detected 621 events attributable to cosmic gamma-rays. However, the field of gamma-ray astronomy took great leaps forward with the SAS-2 (1972) and the COS-B (1975-1982) satellites. These two satellites provided an exciting view into the high-energy universe (sometimes called the 'violent' universe, because the kinds of events in space that produce gamma-rays tend to be explosions, high-speed collisions, and such). They confirmed the earlier findings of the gamma-ray background, produced the first detailed map of the sky at gamma-ray wavelengths, and detected a number of point sources. However, the poor resolution of the instruments made it impossible to identify most of these point sources with individual stars or stellar systems.
Early discoveries
Perhaps the most spectacular discovery in gamma-ray astronomy came in the late 1960s and early 1970s from a constellation of defense satellites which were put into orbit for a completely different reason. Detectors on board the Vela satellite series, designed to detect flashes of gamma-rays from nuclear bomb blasts, began to record bursts of gamma-rays -- not from the vicinity of the Earth, but from deep space! Today, these gamma-ray bursts are seen to last for fractions of a second to minutes, popping off like cosmic flashbulbs from unexpected directions, flickering, and then fading after briefly dominating the gamma-ray sky. Studied for over 25 years now with instruments on board a variety of satellites and space probes, including Soviet Venera spacecraft and the Pioneer Venus Orbiter, the sources of these enigmatic high-energy flashes remain a mystery. They appear to come from far away in the Universe, and currently the most likely theory seems to be that at least some of them come from so-called hypernova explosions - supernovas creating black holes rather than neutron stars. The Swift spacecraft was launched in November, 2004. It is designed to provide rapid location and follow-up for a large sample of gamma-ray bursts.Recent observatories
In 1977, NASA announced plans to build a "great observatory" for gamma-ray astronomy. The Compton Gamma-Ray Observatory (CGRO) was designed to take advantage of the major advances in detector technology during the 1980s, and was launched in 1991. The satellite carried four major instruments which have greatly improved the spatial and temporal resolution of gamma-ray observations. The CGRO provided large amounts of data which are being used to improve our understanding of the high-energy processes in our Universe. CGRO was de-orbited in June 2000 as a result of the failure of one of its stabilizing gyroscopes.Currently, the main space-based gamma ray observatory is the INTErnational Gamma-Ray Astrophysics Laboratory, (INTEGRAL). INTEGRAL is an ESA mission with contributions from Czech, Poland, USA and Russia. It was launched on 17 October 2002.
Very energetic gamma-rays can also be detected by ground based experiments. The Imaging Atmospheric Cherenkov Telescope technique currently achieves the highest sensitivity. The Crab Nebula, a steady source of so called TeV gamma-rays was first detected in 1989 by the Whipple Observatory (Az, USA). Modern Cherenkov telescope experiments like H.E.S.S., VERITAS, MAGIC, and CANGAROO III can detect the Crab Nebula in a few minutes. The most energetic photons (up to 16 TeV) observed from an extragalactic object originate from the blazar Markarian 501 (Mrk 501). These measurements were done by the High-Energy-Gamma-Ray Astronomy (HEGRA) air Cherenkov telescopes.
Gamma-ray astronomy is mostly dominated by the number of photons that can be detected. Larger area detectors and better background suppression are essential for progress in the field.
See also
External links
- The HEGRA Atmospheric Cherenkov Telescope System
- The HESS Ground Based Gamma-Ray Experiment
- The MAGIC Telescope Project
- The VERITAS Ground Based Gamma-Ray Experiment
- The space-borne INTEGRAL observatory
- NASA's Swift gamma-ray burst mission
- The CACTUS Ground Based Air Cherenkov Telescope
- TACTIC(TeV Gamma-Ray Telescope)
Astronomy is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation).
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cosmos is an orderly or harmonious system. It originates from a Greek term κόσμος meaning "order, orderly arrangement, ornaments," and is the antithetical concept of chaos.
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For the music band, see .
Gamma rays or gamma-ray (denoted as γ) are forms of electromagnetic radiation (EMR) or light emissions of a specific frequency produced from sub-atomic particle interaction, such as electron-positron annihilation and..... Click the link for more information.
For the music band, see .
Gamma rays or gamma-ray (denoted as γ) are forms of electromagnetic radiation (EMR) or light emissions of a specific frequency produced from sub-atomic particle interaction, such as electron-positron annihilation and..... Click the link for more information.
Photon
Photons emitted in a coherent beam from a laser
Composition: Elementary particle
Family: Boson
Group: Gauge boson
Interaction: Electromagnetic
Theorized: Albert Einstein (1905–17)
Symbol: or
Mass: 0[1]
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Photons emitted in a coherent beam from a laser
Composition: Elementary particle
Family: Boson
Group: Gauge boson
Interaction: Electromagnetic
Theorized: Albert Einstein (1905–17)
Symbol: or
Mass: 0[1]
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Cosmic rays are energetic particles originating from space that impinge on Earth's atmosphere. Almost 90% of all the incoming cosmic ray particles are protons, about 9% are helium nuclei (alpha particles) and about 1% are electrons.
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interstellar medium (or ISM) is the name astronomers give to the gas and dust that pervade interstellar space. While the interstellar medium refers to the matter that exists between the stars within a galaxy, the energy, in the form of electromagnetic radiation, that
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supernova (plural: supernovae or supernovas) is a stellar explosion that creates an extremely luminous object. A supernova causes a burst of radiation that may briefly outshine its entire host galaxy before fading from view over several weeks or months.
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Electron
Theoretical estimates of the electron density for the first few hydrogen atom electron orbitals shown as cross-sections with color-coded probability density
Composition: Elementary particle
Family: Fermion
Group: Lepton
Generation: First
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Theoretical estimates of the electron density for the first few hydrogen atom electron orbitals shown as cross-sections with color-coded probability density
Composition: Elementary particle
Family: Fermion
Group: Lepton
Generation: First
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magnetic field is a field that permeates space and which exerts a magnetic force on moving electric charges and magnetic dipoles. Magnetic fields surround electric currents, magnetic dipoles, and changing electric fields.
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Centuries: 19th century - 20th century - 21st century
1930s 1940s 1950s - 1960s - 1970s 1980s 1990s
1960 1961 1962 1963 1964
1965 1966 1967 1968 1969
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Their 1960s decade refers to the years from 1960 to 1969, inclusive.
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1930s 1940s 1950s - 1960s - 1970s 1980s 1990s
1960 1961 1962 1963 1964
1965 1966 1967 1968 1969
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Their 1960s decade refers to the years from 1960 to 1969, inclusive.
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balloon is a flexible bag normally filled with a gas, such as helium, hydrogen, nitrous oxide or air. Early balloons were made of dried animal bladders. Modern balloons can be made from materials such as rubber, latex, polychloroprene or a nylon fabric.
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Explorer 11, also known as S15, was the orbital spacecraft that carried the first gamma ray telescope. This was the earliest beginnings of gamma-ray astronomy. Launched on 27 April 1961 by a Juno II rocket the satellite returned data until early September, when power supply
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Solar Maximum Mission satellite (or SolarMax) was designed to investigate solar phenomenon, particularly solar flares. It was launched on February 14, 1980.
Whilst not unique in this endeavour, the SMM was notable in that its useful life compared with similar spacecraft was
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Whilst not unique in this endeavour, the SMM was notable in that its useful life compared with similar spacecraft was
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Reuven Ramaty (1937 - 2001) was a pioneer in the fields of solar physics, gamma-ray astronomy, nuclear astrophysics, and cosmic rays. He was a HESSI Co-Investigator and one of the founding members of the HESSI team.
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Cos-B was the first European Space Agency mission to study gamma-ray sources. The mission consisted of a satellite containing X-ray and gamma-ray detectors, which was launched by NASA on behalf of the ESA on August 9, 1975.
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Vela was the name of a group of satellites developed as the Vela Hotel element of Project Vela by the United States to monitor compliance with the 1963 Partial Test Ban Treaty by the Soviet Union, and other nuclear-capable states.
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Gamma-ray bursts (GRBs) are probably the most luminous events in the universe since the Big Bang. They are flashes of gamma rays coming from seemingly random places in deep space at random times.
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Venera (Russian: Венера;) series of probes was developed by the USSR between 1961 and 1984 to gather data from Venus. As with some of the USSR's other planetary probes, the later versions were launched in pairs with a second vehicle being
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The Pioneer mission to Venus consisted of two components, launched separately. Pioneer Venus 1 or Pioneer Venus Orbiter was launched in 1978 and studied the planet for more than a decade after orbital insertion in 1978.
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Hypernova (pl. hypernovae) refers to an exceptionally large star that collapses at the end of its lifespan—for example, a collapsar, or a large supernova. Up until the 1990s, it had a more specific meaning to refer to an explosion with an energy of over
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black hole is a region of space in which the gravitational field is so powerful that nothing can escape after having fallen past the event horizon. The name comes from the fact that even electromagnetic radiation (e.g. light) is unable to escape, rendering the interior invisible.
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129: 312.
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19th century - 20th century - 21st century
1940s 1950s 1960s - 1970s - 1980s 1990s 2000s
1974 1975 1976 - 1977 - 1978 1979 1980
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1940s 1950s 1960s - 1970s - 1980s 1990s 2000s
1974 1975 1976 - 1977 - 1978 1979 1980
- Also: 1977 (album) by Ash.
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National Aeronautics and Space Administration
NASA logo
Motto: For the Benefit of All[1]
NASA seal
Agency overview
Formed 29 July 1958
Headquarters Washington D.C.
Annual Budget $16.
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NASA logo
Motto: For the Benefit of All[1]
NASA seal
Agency overview
Formed 29 July 1958
Headquarters Washington D.C.
Annual Budget $16.
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The Compton Gamma Ray Observatory (CGRO) was the second of the NASA "Great Observatories" to be launched to space, following the Hubble Space Telescope. CGRO was named after Dr. Arthur Holly Compton (Washington University in St.
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A gyroscope is a device for measuring or maintaining orientation, based on the principle of conservation of angular momentum. The device is a spinning wheel whose axle is free to take any orientation.
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INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) is detecting some of the most energetic radiation that comes from space. It is the most sensitive gamma ray observatory ever launched.
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October 17 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.
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Events
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