Pin-pointing Black Holes: Upgraded European Network Of Radio Telescopes Has Sharper Vision Than Hubble of Distant Galaxies

Dr Michael Garrett

Joint Institute for Very Long Baseline Interferometry in Europe

+31 (0)521 596511

garrett@jive.nl

The most detailed images ever made of faint, distant radio galaxies, located billions of light years from Earth,
reveal that many of them harbour central massive black holes, adding 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 those from the Hubble Space Telescope, the new pictures (see
www.nfra.nl/’mag/hdf/evn/pr/) give a fresh insight into what is happening in the centre of some of these galaxies.
The images, generated by the recently upgraded European VLBI Network (EVN) 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 25000 Gigabytes of data in total. By means of a special, purpose-built
super-computer (operated by the National Radio Astronomy Observatory in Socorro, USA), the magnetic tapes
were later played back and combined together to form a super-sensitive, giant radio telescope of continental
dimensions. For this experiment, the network was focussed 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.

Peer reviewed publication and references
Astronomy & Astrophysics (Springer-verlag)
February 1, vol. 366 number 2.

Reference URL : www.jive.nl/~mag/hdf/evn/pr/