Colloq Abstract - Alessandro Paduano
October 28, 2022
11:00am Mountain
Alessandro Paduano (Curtin/ICRAR)
In search of faintly accreting black holes: The deepest radio survey of 47 Tucanae
Abstract
Globular clusters contain hundreds of thousands of stars and stellar remnants and have been observed to host large populations of millisecond pulsars and accreting white dwarfs, in addition to a handful of black holes and other transients. Globular clusters have also been suggested to be the birthplace of the compact binaries that merge to create gravitational wave events and may also host intermediate-mass black holes. This rich collection of different source classes makes globular clusters ideal targets for deep observational campaigns. In this talk, I will present the initial results of a 480-hr radio survey with the Australia Telescope Compact Array (ATCA) of the nearby, dynamically active globular cluster 47 Tucanae (47 Tuc). These data have allowed us to produce the deepest image ever made with ATCA, reaching an RMS noise level of ~790 nano-Jy, comparable to what is expected from the Square Kilometre Array. I will discuss the detected radio sources in this cluster, mainly focusing on a compact radio source at the cluster centre, and discuss the implications that this source has for the existence of a central intermediate-mass black hole in 47 Tuc. I will also discuss the prospects of deep radio studies with the next generation of radio facilities such as the Square Kilometre Array and the Next-Generation Very Large Array.
