I can see clearly now the Quasar’s home…

The new Low Frequency Array has had a test run. Its target was the well known and previous imaged quasar (quasi stellar object – a bright jet and set of radiation sources around a feeding supermassive black hole in the centre of a galaxy) 3C 196. 3C 196 had already been identified and had its structures mapped in shorter wavelengths, so the test was for the new interferometer to be able to see the same structures at longer wavelengths.

Interferometry, in this case, is the adding together of signals from distant receivers. The resolution of an interferometer then depends on this separation rather than the aperture size (referred to as aperture synthesis) and the sensitivity of the combined instrument is equivalent to the combined sensitivities of the individual instruments (a function of active surface area).

As expected, when the bits contained just in the Netherlands were switched on, 3C 196 appeared as a fuzzy blob. When the signals from the German stations were added to these, the blob resolved to show the intricate structures expected. There are further stations to be added to the present lot before the full array is commissioned, so resolution is expected to increase, now they know the thing works. More details at Astronomy Now.


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