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Station chat with kids
Expedition 9 commander Gennedy Padalka and flight engineer Mike Fincke talk about life aboard the International Space Station during an in-flight educational event with students at the Carnegie Science Center in Pittsburgh. (19min 00sec file)
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ISS educational event
The International Space Station's Expedition 9 crew hold an educational talk with students and members of the National Guard Bureau in Charleston, West Virginia. (19min 53sec file)
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NASA chief visits KSC
NASA Administrator Sean O'Keefe tours the hurricane damage at Kennedy Space Center. (5min 50sec file)
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Shuttle news briefing
The Stafford-Covey Return to Flight Task Group's co-chairmen, former astronauts Tom Stafford and Dick Covey, hold a news conference Thursday to update reporters on NASA's efforts to prepare the next space shuttle mission. (47min 01sec file)
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Genesis crash lands
The Genesis sample return capsule tumbles through the sky and impacts the desert floor in Utah after its speed-slowing chute and parafoil failed to deploy for a mid-air recovery by a helicopter. (2min 29sec file)
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Slow-motion
This slow-motion video shows the Genesis capsule slamming into the ground. (1min 06sec file)
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Aerial views of crater
Aerial views show the Genesis capsule half buried in the Utah desert floor after its landing system suffered a failure. (1min 53sec file)
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High energy mystery lurks at the galactic centre
PARTICLE PHYSICS AND ASTRONOMY RESEARCH COUNCIL
Posted: September 22, 2004

A mystery lurking at the centre of our own Milky Way galaxy - an object radiating high-energy gamma rays - has been detected by a team of UK astronomers working with international partners. Their research, published today (September 22nd) in the Journal Astronomy and Astrophysics, was carried out using the High Energy Stereoscopic System (H.E.S.S.), an array of four telescopes, in Namibia, South-West Africa.

The Galactic Centre harbours a number of potential gamma-ray sources, including a supermassive black hole, remnants of supernova explosions and possibly an accumulation of exotic 'dark matter' particles, each of which should emit the radiation slightly differently. The radiation observed by the H.E.S.S. team comes from a region very near Sagittarius A*, the black hole at the centre of the galaxy. According to most theories of dark matter, it is too energetic to have been created by the annihilation of dark matter particles. The observed energy spectrum best fits theories of the source being a giant supernova explosion, which should produce a constant stream of radiation.

Dr. Paula Chadwick of the University of Durham said, "We know that a giant supernova exploded in this region 10,000 years ago. Such an explosion could accelerate cosmic gamma rays to the high energies we have seen - a billion times more energy than the radiation used for X-rays in hospitals. But further observations will be needed to determine the exact source."

Professor Ian Halliday, Chief Executive of the Particle Physics and Astronomy Research Council (PPARC) which funds UK involvement in H.E.S.S. said; "Science continues to throw out the unexpected as we push back the frontiers of knowledge." Halliday added "The centre of our Galaxy is a mysterious place, home to exotic phenomena such as a black hole and dark matter. Finding out which of these sources produced the gamma-rays will tell us a lot about the processes taking place in the very heart of the Milky Way."

However, the team's theory doesn't fit with earlier results obtained by the Japanese /Australian CANGAROO instrument or the US Whipple instrument. Both of these have detected high-energy gamma rays from the Galactic Centre in the past (observations from 1995-2002), though not with the same precision as H.E.S.S, and they were unable to pinpoint the exact location as H.E.S.S. has now done, making it harder to deduce the source. These previous results have different characteristics to the H.E.S.S. observations. It is possible that the gamma-ray source at the Galactic Centre varies over the timescale of a year, suggesting that the source is in fact a variable object, such as the central black hole.

The H.E.S.S. team hopes to unravel the mystery with further observations of the Galactic Centre over the next year or two. The full array of four telescopes will be inaugurated on September 29th 2004, see

The H.E.S.S. collaboration

The High Energy Stereoscopic System (H.E.S.S.) team consists of scientists from Germany, France, the UK, the Czech Republic, Ireland, Armenia, South Africa and Namibia.

The H.E.S.S. array

Over the last few years, the H.E.S.S. collaboration have been building a system of four telescopes in the Khomas Highland region of Namibia, to study very-high-energy gamma rays from cosmic particle accelerators. The telescopes, known as Cherenkov telescopes, image the light created when high-energy cosmic gamma rays are absorbed in the atmosphere, and have opened a new energy domain for astronomy. The H.E.S.S. telescopes each feature mirrors of area 107 square metres, and are equipped with highly sensitive and very fast 960-pixel light detectors in the focal planes. Construction of the telescope system started in 2001; the fourth telescope was commissioned in December 2003. Observations were being made even while the system was being built, first using a single telescope, then with two and three telescopes. While only the complete four-telescope system provides the full performance, the first H.E.S.S. telescope alone was already superior to any of the instruments operated previously in the southern hemisphere. Among the first targets to be observed with a two-telescope instrument was the Galactic Centre.

Ares 1-X Patch
The official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.
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Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
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Expedition 21
The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.
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Hubble Patch
The official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase.
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