The Parkes Radio Telescope looks into the heart of the Galaxy – Alan Plummer reports
The Parkes Radio Telescope. Astronomy can be done in many ways: Gamma rays, X-rays, ultraviolet, visual light, infra-red and radio waves all carry information about the universe. Photograph by John Sarkissian, ATNF.
Astronomer Fred Watson calls the Parkes Observatory ‘the most beautiful radio telescope in the world’. On his recommendation, we – me, wife, kids, etc – made the trip. I can easily believe that Fred is right. The site is beautiful, the Visitors Center is second to none, and the whole family was educated and entertained.
Much of the telescope’s public image stems from the movie ‘The Dish’, which features its communications role in the NASA moon missions. But the primary work of the Observatory lies elsewhere. It is not possible to describe here all that the facility does, but the Visitors Center provide information on what it is doing when you are there. For us, that was Pulsar timing (Pulsars are a specialty of the Observatory) and the helping with two satellite observatory missions, GLAST & AGILE.
A direct feed from the astronomer’s instruments into the public area showed the telescope pointing at 17h 46’ 00.0” -30° 00’ 00.0”. That was straight up, and not far from the Sun. So radio telescopes work in the day! Below is an optical photograph (taken at night!) from the Aladin Sky Atlas showing those coordinates: visually. There is nothing there.
The sky at 17h 46’ 00.0” -30° 00’ 00.0”. Picture from the Aladin Sky Atlas
The indicated direction is right in the plane of the Galaxy where all the dust is, and into the central Hub. Radio frequency waves go through this dust where visible light does not, and there are many ‘radio loud’ objects near the center of the Galaxy.
The invisible target at the above coordinates was in fact the radio source GAL 359.1-00.54. This turns out to be a tight wrapped and strong magnetic tube-like structure, or filament, generating, obviously, radio waves. Turbulence from massive star forming areas, ‘windy’ mass-loss from giant stars, supernova explosions, strong radiation, etc, can ‘wind up’ the weak magnetic field of the Galaxy into stronger filaments. Then, interactions with giant molecular clouds can send them waving around the Hub of the Galaxy like ultra slow motion Medusa’s Hair. Some have names like ‘The Snake’ and ‘The Mouse’ after the patterns they make when they are plotted.
GAL 359.1-00.54 is not a Pulsar, which is a single stellar object rather than a structure as described above. So my guess is that this target was to do with either the GLAST or AGILE satellite observatory missions. Anyone who has not been to Parkes, I urge you to go. You won’t regret it.
Alan Plummer
Linden Observatory
