PRESS RELEASE Monday 4th October 2004
Astronomers Demonstrate a Global Internet Telescope
Using cutting-edge technology, the researchers have managed to observe both a distant star and the "monster in the middle" of a galaxy far away from our Milky Way. For this, they have used the world's research computer networks to create a giant virtual telescope. This allows imaging of the objects with unprecedented detail, and in real-time, which would have been impossible only a few years ago.
The star chosen for this remarkable demonstration, IRC+10420, is one of the most unusual in the sky. Surrounded by clouds of dusty gas and emitting strongly in radio waves, the object is poised at the end of its life, heading toward a cataclysmic explosion known as a 'supernova'. In contrast, the active galactic nucleus studied is that of the galaxy 3C166, situated 3.2 billion light years from the Earth.
These new observations give an exciting glimpse of the future of radio astronomy. Using research networks, astronomers will be able to see deeper into the distant Universe and capture unpredictable, transient events as they happen. Astronomers always seek to improve the resolving power of their telescopes, maximising the detail that can be seen; the bigger the telescope, the better the resolution. VLBI (or Very Long Baseline Interferometry) is used by radio astronomers to image the sky in supreme detail. Instead of using a single radio dish, arrays of telescopes are linked together across whole countries or even continents. When the signals are combined in a specialised computer, the resulting image has a resolution equal to that of a telescope as big as the maximum antenna separation.
Until now, VLBI has been severely hampered because the data had to be recorded onto tape and then shipped to a central processing facility for analysis. Consequently, radio astronomers were unable to judge the success of their endeavours until weeks or months after the observations were made. The solution, to link the telescopes electronically in real-time, now enables them to analyse the data as it arrives. This technique, naturally called e-VLBI, is now possible as high-bandwidth network connectivity has become a reality.
On 22nd September, 20-hour long observations
the European VLBI Network (EVN) involved radio telescopes in the
Each telescope was connected to its country's
National Research and Education Network , and the data routed at
Mbits/second per telescope through GEANT, the pan-European research
SURFnet, the Dutch network. The data were then delivered to the Joint
for VLBI in Europe (JIVE) in the
Although the scientific goals of this
experiment were modest, the e-VLBI observations of IRC+10420 open up
possibility of watching the structures of astrophysical objects as they
IRC+10420 is a supergiant star in the constellation of
It is believed that IRC+10420 is rapidly evolving toward the end of its life. At some point, maybe thousands of years from now, maybe tomorrow, the star is expected to blow itself apart in one of the most energetic phenomena known in the Universe - a 'supernova'. The resulting cloud of material will eventually form a new generation of stars and planetary systems. With the incredible power of e-VLBI, radio astronomers are now poised, to catch the details as they happen and study these physical processes that are so important to the structure of our Galaxy and to life itself.
More distant, and on a larger scale, the galaxy 3C166 contains an active nucleus which is feeding material from the center of the galaxy, through narrow "jets", to huge emission lobes situated far outside of the galaxy itself. The active nucleus, or "central engine" as it is often known, is believed to contain a super-massive black hole providing the energy to power the out-flowing jets. In the accompanying figure, the very center of the galaxy is imaged, and the majority of the radio emission is found to originate in a region that is smaller than 88 light years, emphasising the presence of a highly compact object, believed to be the black hole.
The emergent technology of e-VLBI is set to revolutionise radio astronomy. As network bandwidths increase, so too will the sensitivity of e-VLBI arrays, allowing clearer views of the furthest and faintest regions of space. Dr Mike Garrett, JIVE Director, commented, "These results provide a glimpse of the enormous potential of e-VLBI. The rapid progress in global communications networks should permit us to connect together the largest radio telescopes in the world at speeds exceeding tens of Gigabits per second over the next few years. The death throes of the first massive stars in the Universe, the emerging jets of matter from the central black-holes of the first galaxies, will be revealed in exquisite detail."
Figure 1: (left) A low-resolution image of
IRC+10420 taken with the
The spectrum of IRC+10420 (a plot of
signal strength as it changes with frequency of the radio waves), as
during the EVN e-VLBI observations of 22nd September. The total
of the emission shows that the shell of IRC+10420 is expanding at about
Figure 3: A transatlantic e-VLBI image of the
nuclear region of the radio galaxy 3C166. The distance of this object
billion light years, and its size is less than 88 light years. A super
black hole is believed to reside in the center of this strong radio
Pictures taken at the Arecibo Observatory during the e-VLBI run on September 22, 2004 (click to enlarge).
Left frame: back: Tapasi Ghosh, José Cruz, Bill Genter, Arun Venkataraman; front: Chris Salter, Emmanuel Momjian.
Right frame: Arun Venkataraman, Bill Genter, Chris Salter, Tapasi Ghosh and Emmanuel Momjian
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