News

Physics students competing for prizes at the House of Commons

(10 March 2005)

Two Durham University students have been selected to present posters of their work at the Annual Presentations by Britain’s Top Younger Scientists Engineers and Technologists at the House of Commons on Monday 14th March 2005.

Anthony Brown and Noam Libeskind, two physics research students, are attending the lunch-time reception as part of National Science Week. They will be competing for the 2005 Westminster Medal and a £1000 prize.

The event, led by British scientist Dr Eric Wharton, is designed to encourage, support and promote Britain's and Europe's younger researchers, who are the "engine-room" of continued advancement and progress in research and R&D in science, engineering, medicine and technology.

Anthony’s research project has to do with Very High Energy (VHE) gamma ray astronomy research, of which Durham is at the fore-front as a member of the High Energy Stereoscopic System collaboration (H.E.S.S.). The H.E.S.S. telescopes are in Namibia, and Anthony will be presenting some of the interesting results from the first year of its operation.

Noam Libeskind presents work, entitled The Satellites of the Milky Way: The Great Pancake, in conjunction with Professor Carlos Frenk and Dr. Shaun Cole. He presents findings on why the arrangement of the Milky Way’s satellites appears in a pancake-like shape, as opposed to a spherical shape, puzzling astronomers for centuries.

The event is held in The Terrace Marquee and the Churchill Room, which encompasses fields of Science, Engineering, Medicine and Technology. As well as competing for the Westminster Medal and a £1000 prize, there will also be Runner-Up prizes.

ends

For more information contact: Dr Lowry McComb, Director of Postgraduate Training Department of Physics, Tel: (+44) 0191 334 3744, e-mail: t.j.l.mccomb@dur.ac.uk

Media contact: Joy Davis, Public Relations, Durham University Tel: (+44) 0191 334 6803, e-mail: joy.davis@durham.ac.uk

Other information: http://www.setforeurope.org/hoc05/index.html

Notes to editors:

H.E.S.S. OPENS A NEW WINDOW TO THE HIGH ENERGY UNIVERSE

Anthony Brown Very High Energy Gamma Ray Group, Department of Physics, University of Durham

As a member of the High Energy Stereoscopic System collaboration, H.E.S.S., Durham University is at the fore-front of Very High Energy (VHE) gamma ray astronomy research. Fully commissioned in December 2003, the H.E.S.S. telescope array consists of 4 x 13 metre diameter telescopes, and is located in Namibia, Africa, free of the light pollution from big city lights. The H.E.S.S. telescope array was built with the aim of imaging the universe in the light of the highest energy gamma rays; a regime of light a billion times more energetic then hospital X-rays and about which very little is known. These VHE gamma rays allow us to explore some of the most extreme, most interesting objects in the Universe, teaching us about the laws of nature within these extreme environments. This is something that we are unable to do in a scientific laboratory on Earth.

Most of the radiation we observe, such as light from the sun, is thermal radiation, created by hot bodies. This doesn’t however apply to VHE gamma rays, as basic considerations state that no matter can be hot enough to emit VHE gamma rays. This means that VHE gamma rays are created by unusual particle accelerators in space. These conditions occur in the remnants of stellar explosions and in the space around giant black holes. Here I present some of the most interesting results from the first year of H.E.S.S. operation, the first ever VHE gamma ray image of a supernova remnant, the first ever strong detection of VHE gamma rays from the centre of our galaxy and continual results from the super-massive black hole in the distant galaxy, PKS 2155-304, which was first detected as a VHE source by Durham University during the late 90’s.

The Satellites of the Milky Way: The Great Pancake Noam I Libeskind, Carlos S Frenk, Shaun M Cole. Institute for Computational Cosmology, Durham University,

All galaxies, including the Milky Way, have smaller satellite galaxies that orbit around them. The dominant form of matter in these galaxies is known as dark matter – invisible matter whose existence is inferred by the influence it exerts on visible stars. According to the current cosmological orthodoxy, the formation of galaxies is driven by the gravity of the dark matter in a hierarchical way: small sub-galactic units are the first to form and subsequently merge together to produce the majestic objects – like the Milky Way – that we see today. Cosmological theory predicts that galaxies are imbedded in large, nearly spherical halos. If the satellite galaxies that orbit in these halos were representative of a background population of galaxies, they too should have a uniform spherical distribution, like that of the Milky Ways dark halo. Yet, for nearly a century, astronomers have been puzzled by the bizarre arrangement of the Milky Way's satellites, which appear to lie on a great circle exhibiting a flattened, pancake-like distribution. What is the origin of this distribution and does it contradict cosmological orthodoxy? To answer these questions, we have carried out sophisticated supercomputer simulations of the formation of cosmic structure. By simulating the evolution of a huge volume of the universe, we are able to focus on the birth of a galaxy and its satellites. Surprisingly, we find that the galaxies that end up as satellites are not typical objects but instead, amplify patterns in the large-scale distribution of dark matter. As a result, their final distribution is pancake-like, just like that observed in the Milky Way. Far from disproving the standard paradigm, our work provides strong support for our current view of the origin of the cosmos.