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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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