Radio Telescope

Malta now has a radio telescope. This is a great step forward for the University of Malta as it helps speed up research.

The Department of Physics, Faculty of Science and the Institute of Space Sciences & Astronomy (ISSA; both at the University of Malta) have just acquired a 5.3m dual-reflector parabolic dish, as part of a European Regional Development Fund (ERDF) project to extend postgraduate research lab facilities. The radio telescope will now allow students and researchers to study celestial objects such as the sun or the centre of the galaxy through the radio waves they emit.

Quick Specs
Dish diameter: 5.3m

Feed horns: L-Band and K-band

Gain: 44 dBi @ 4GHz

Observing modes: Continuum and line observation

Total weight (including pedestal): 1900 kg

Surface accuracy: 0.5mm

PC-based automated control unit

toolkit03

toolkit02When pointed to a radio-loud celestial object (an object which emits large amounts of radio waves, such as the sun), the telescope will receive radio waves from these sources and convert them to voltage readings in the feed. The converted signal is then transmitted to a digitiser that converts these signals into bits and bytes.

The digitised signals are then processed and broken down into the different frequency counterparts (similar to what a car radio does with the radio waves it receives from its antenna), which allows for continuum observation of the skies above. The telescope provides a test-bed for several research initiatives being undertaken at ISSA.

Some of its specialisations include improving the hardware and software processing back-ends for radio telescopes. The on-site telescope can speed up this sort of research immensely. ISSA is part of the largest radio telescope project in the world: the SKA (Square Kilometre Array).

Galactic rotation dynamics in modified gravity

In the last 100 years, Einstein’s theory of general relativity has proven invaluable to explain the nature of the universe. That being said, Einstein’s model of gravity does at times fail to comply with what we actually observe when looking up at the night sky.

Galaxies offer one of the most impressive laboratories where general relativity just does not work. Stellar objects in galaxies tend to orbit the galactic centre of mass. General relativity predicts that as one goes further from the centre of the galaxy, these orbital speeds drop off. Observational data shows that these velocities tend to stay constant along the radius of a galaxy. However, dark matter can be artificially introduced to account for this. The other argument is that such failures indicate the inability of general relativity to fully explain how the universe works. If this is so, it seems necessary to construct what are called alternative or modified theories of gravity. Such theories would have to be capable of correctly explaining all observed phenomena including those that general relativity fails to produce.

Andrew Finch (supervised by Dr Jackson Levi Said) is looking into the new concept of treating gravity as a torsional dominated system instead of a curvature dominated one, which is the concept explained by general relativity. The new models are being developed with the intention of agreeing with galactic rotation curves while managing to explain everything that general relativity already does. It is only possible to vigorously test such models because of the large amount of freely available data which has been gathered on galaxies. As models are obtained, the cluster in the ISSA (Institute of Space Science and Astronomy) laboratory is being used in order to determine model parameters. Using this data, Finch aims to compare Einstein’s theory with the new model being developed. Will it improve on Einstein’s ideas? Only Finch will tell…

This research is being performed as part of a Masters Degree in Astrophysics being read at the Institute of Space Sciences and Astronomy, University of Malta.

Andrew Finch