ATCA: Telescope snaps 'most sensitive' image of ancient galaxy cluster

The Australia based radio telescope spent over 450 hours capturing an exceptionally sensitive and ultra deep image of a globular cluster dubbed 47 Tucanae. 47 Tucanae, first spotted in the 1700s, is recognized as the second brightest globular cluster visible to the human eye in the night sky. This wide observation was conducted using the CSIRO's Australia Telescope Compact Array (ATCA) in Gomeroi Country, which was directed by the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) in Western Australia.

"Globular clusters are very old, giant balls of stars that we see around the Milky Way," said Arash Bahramian from ICRAR's Curtin University "Our image is of 47 Tucanae, one of the most massive globular clusters in the galaxy. It has over a million stars and a very bright, very dense core," added Bahramian in the Detection of faint radio signal While creating this highly sensitive radio image, the study team uncovered a previously unknown weak radio signal from the cluster's core.

The team is exploring two potential explanations for the origin of this signal. "The first is that 47 Tucanae could contain a black hole with a mass somewhere between the supermassive black holes found in the centers of galaxies and the stellar black holes created by collapsed stars," said Alessandro Paduano, lead author from ICRAR's Curtin University node.

"While intermediate mass black holes are thought to exist in globular clusters, there hasn't been a clear detection of one yet. If this signal turns out to be a black hole, it would be a highly significant discovery and the first ever radio detection of one inside a cluster," added Paduano.

The team postulates that the alternative origin of this radio signal might be attributed to the existence of a rapidly rotating neutron star, commonly known as a pulsar. "A pulsar this close to a cluster center is also a scientifically interesting discovery, as it could be used to search for a central black hole that is yet to be detected," mentioned Paduano.

The upcoming SKA radio telescopes, presently under construction in Australia and South Africa under the auspices of the SKA Observatory, will be capable of producing ultra sensitive images of celestial objects and star clusters. The authors highlight that these detailed radio images have the potential to broaden their understanding of the universe and solve some of the most fundamental cosmic puzzles.

"We managed to achieve close to SKA quality science with the current generation of radio telescopes, combining hundreds of hours of observations to reveal the faintest details. It gives us a glimpse of the exciting capabilities the next generation of radio telescopes will achieve when they come online," concluded Bahramian.

The study was published in on January 16 and can be found here..