MeerKAT’s stunning image reveals cosmic threads, ribbons and rings
Thursday, 17 June 2021
A new study using the MeerKAT radio telescope has produced a striking image showing a combination of cosmic features never before seen, revealing unexpected details of the inner workings of enormous radio galaxies.
At the center of the giant elliptical galaxy IC 4296 is a rotating black hole with a mass of a billion suns. Energy released by matter falling onto the black hole generates two opposing radio jets containing magnetic fields and relativistic electrons. After travelling through intergalactic space at the speed of light for 160 million years, these radio waves were detected by the South African Radio Astronomy Observatory’s MeerKAT telescope, located in the Karoo region of the Northern Cape province of South Africa.
The Fanaroff-Riley Type I radio galaxy IC 4296 dominates this spectacular vista, wider than the full moon on the sky. MeerKAT radio data are represented in red/orange hues in this composite view. The visible light image from the SuperCOSMOS Sky Survey shows the central giant elliptical galaxy, as well as numerous unrelated galaxies and foreground stars in the Milky Way. Credit: SARAO, SSS, S. Dagnello and W. Cotton (NRAO/AUI/NSF). Adapted from J. Condon et al., “Threads, Ribbons, and Rings in the Radio Galaxy IC 4296” (The Astrophysical Journal, in press).
The bright spines of the initially straight jets become unstable just outside the galaxy, where some of the electrons escape to create several faint radio “threads” below IC 4296. Between the bright jets and the outer lobes are smooth “ribbons” filling channels excavated from the surrounding gas by defunct jets from an earlier period of activity. The ribbons are eventually stopped by intergalactic gas, nearly a million light-years from the central galaxy (a distance equal to 10 times the diameter of our Milky Way home galaxy), and form the “smoke rings” visible in the left radio lobe.
Jim Condon of the US National Radio Astronomy Observatory – lead author of the study just accepted for publication in The Astrophysical Journal that summarizes this research done by a US-South African team – says that “only MeerKAT’s unique combination of sensitivity, angular resolution, and dynamic range allowed the discovery of these threads, ribbons, and rings” in this previously well-studied galaxy.
As noted by the anonymous reviewer of the manuscript submitted for publication, “it is clear that new results like this from MeerKAT and other SKA pathfinders are set to overhaul our understanding of extragalactic radio sources”.
For more information contact
Dr Fernando Camilo
SARAO Chief Scientist