Processing data for MeerKAT’s image of the galactic centre

Processing data for MeerKAT’s image of the Galactic Centre


MeerKAT conducted a wide area imaging survey of the galactic centre region as part of its commissioning phase. Radio waves pass through the large amounts of dust that obscure the region at optical wavelengths, allowing a unique view of the environment that surrounds the 4 million solar mass black hole at the heart of the Milky Way. The field is notoriously difficult to image with radio interferometers due to the bright emission on all scales, and the variability of the strong, compact radio source named Sagitarrius A* (Sgr A*) coincident with the black hole at the centre of the Milky Way.

The observations consisted of 26 individual pointings, typically of ten hours each. These were observed almost daily for a month, with the data being pushed to the storage area at IDIA as soon as the observations were complete. IDIA hardware was then used to process these data, with the typical steps being the removal of radio interference, generation of calibration solutions, and then imaging. The data processing kept up with the intense observing schedule, with processing for one day of observations typically taking place as the next observation was being carried out. At the end of the observing campaign the MeerKAT data were combing with single dish data from the Green Bank Telescope in West Virginia, in the United States, resulting in the mosaic that formed the centrepiece of the MeerKAT inauguration in July 2018.

The large storage area, and the fast link to the MeerKAT archive at IDIA were key to processing these observations effectively and timeously.