Galaxies give up their secrets (Forwarded)

News & Events Service
University of Durham
Durham, U.K.

Contact:
Professor Carlos Frenk FRS
Institute for Computational Cosmology, Durham University
Tel: Direct line: 0191 334 3641 Secretary: 0191 334 3635

Tue, 19 July 2005

Galaxies give up their secrets

Astronomers at Durham University are trail-blazing across the galaxies,
using enormous computer power to understand how the universe developed
and explain more about what it contains.

And one of their techniques is to "cook" galaxies from the ingredients
of the universe and the laws of physics in the form of a computer
simulation. They then compare the results with the known universe to
test theories about how the universe grew.

The dramatic images figure in the latest news release from Research-tv: see
http://www.research-tv.com/stories/t...osmic_cookery/

The Durham work, seen both in flat-screen and in 3-D, are among the
latest results that put the Institute of Computational Cosmology, of
Durham's Physics Department, at the heart of internationally significant
space research.

Professor Carlos Frenk, Director of the Institute of Computational
Cosmology, Department of Physics, Durham University, said: "This is a
task that had challenged cosmologists for about a decade and we were the
first to be able to successfully reproduce the Milky Way Galaxy. It
turns out that what our colleagues had been missing were some very
intricate detail that we call feedback processes whereby the galaxy
forming interacts with galaxies cooling down to make the stars in a
fairly complicated way. This is the first time however that anybody has
been able to make a galaxy that for all intents and purposes could just
be the Milky Way."

The ICC's latest output includes:

* the largest simulation ever of the growth of the cosmos
* discovery of 'superwinds' spreading the dust from a vast galactic
explosion 11.5 billion light years away
* identifying a new source of very high energy gamma rays

As members of the Virgo consortium, an international group of
astrophysicists from the UK, Germany, Canada and the USA, the ICC has
have run the largest and most realistic simulation ever of the growth of
cosmic structure and the formation of galaxies and quasars. It employed
more than 10 billion particles of matter to trace the evolution of the
matter distribution in a section of the Universe.

In another set of observations, a Durham-led team provided the most
direct evidence yet of a galaxy being almost torn apart by explosions
that produce a stream of high-speed material known as "Superwinds". The
observations were made using the 4.2 metre William Herschel Telescope on
La Palma in which the UK is a major stakeholder. Superwinds are vital to
the theory of galaxy formation. It is thought that with Superwinds
galaxies blast a significant part of their gas into intergalactic space
at speeds of up to several hundred miles per second. They carry heavy
elements -- star dust -- far from their production sites providing raw
material for planets and life across the Universe.

And in another research stream, results have produced a new
understanding of the universe as viewed in gamma rays, producing the
first-ever gamma ray images of astronomical objects and the first scan
of a large region around the centre of the galaxy. The object that is
producing the high energy radiation is thought to be a 'microquasar'.
These objects consist of two stars in orbit around each other. One star
is an ordinary star, but the other has used up all its nuclear fuel,
leaving behind a compact corpse. Depending on the mass of the star that
produced it, this compact object is either a neutron star or a black
hole, but either way its strong gravitational pull draws in matter from
its companion star. This matter spirals down towards the neutron star or
the black hole, in a similar way to water spiralling down a plughole.

Further information:
http://icc.dur.ac.uk/