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Daily University Science News
The
most detailed images ever made of faint, distant radio galaxies
located billions of light years from Earth reveal that many
of them harbor central massive black holes.
These
new images add further support to the belief that super-massive
black holes are inextricably linked with the way galaxies
formed in the early universe.
Because
the radio images are three times sharper than the optical
images from the Hubble Space Telescope, the new pictures
give a fresh insight into what's happening in the center
of some of these galaxies.
Generated
by the recently upgraded European VLBI Network (EVN), the
images are particularly valuable because they penetrate
the dust that often blocks the view of even the most powerful
optical telescopes.
The
pioneering observations were conducted by an international
team of radio astronomers from Europe and the USA. The radio
signals were received by the giant 100-m telescope in Effelsberg,
Germany; the 76-m Lovell Telescope in the UK; the 70-m NASA/DSN
antenna near Madrid in Spain and six other large radio telescopes
located across Europe.
Data
at each of the radio telescopes were archived on high speed
magnetic tape recorders, generating almost 25,000 Gigabytes
of data in total. By means of a special purpose-built supercomputer
(operated by the National Radio Astronomy Observatory in
Socorro, USA), the magnetic tapes were later played back
and combined to form a super-sensitive giant radio telescope
of continental dimensions.
For
this experiment, the network focused on a small region of
sky devoid of bright nearby stars or local galaxies, a sort
of window on the distant universe. Since the Hubble Space
Telescope peered at this same region, this otherwise unremarkable
patch of sky has become famous as the "Hubble Deep
Field" and is now known to contain thousands of galaxies.
The
scientific team that initiated the new radio observations
is led by Dr. Michael Garrett of the Joint Institute for
VLBI in Europe, Dwingeloo, the Netherlands (JIVE), together
with Drs. Simon Garrington and Tom Muxlow of the MERLIN
National Facility, Jodrell Bank Observatory, UK.
Three
radio sources were detected in an area of sky no bigger
than that covered by a grain of sand held up to the night
sky. The results appear in the latest issue of the European
journal, Astronomy and Astrophysics.
According
to Garrett, the team had not expected to detect this many
radio sources.
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