Tricolour image of the monster black hole galaxy system RAD12, newly discovered by RAD@home Citizen scientists, spewing fire at another galaxy. Credit: Ananda Hota, telescopes GMRT (red), CFHT(yellow), MeerKAT (blue)
A unique black hole has been discovered in a galaxy around one billion light years away from Earth1. The black hole is spewing electron-rich radio jets at another galaxy.
The galaxy that hosts the black hole is named RAD12, an elliptical galaxy which has been caught merging with a gas-poor, bigger and brighter elliptical galaxy.
It is a rare system that helps us understand how radio jets from supermassive black holes induce star formation in merging galaxies, says a team of astronomers at the UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai.
Previous observations have shown that supermassive black holes eject gigantic jets that deplete fuel for star formation in elliptical galaxies.
To learn more about this, astronomers and citizen scientists, led by Ananda Hota, monitored radio emissions from RAD12 using the Giant Metrewave Radio Telescope (GMRT) near Pune in India and the South African MeerKAT radio telescope.
They found that the black hole fires jets only in pairs, which move in opposite directions at relativistic speeds, reaching far beyond the visible stars of its host galaxy. After hitting the neighbouring galaxy, named RAD-12-B, each jet is reflected back and forms a mushroom-shaped bubble. A jet is 440,000 light years long, which is much larger than RAD12.
Jet-galaxy interaction triggers young star formation that shows up in ultraviolet-optical colours, but RAD12 does not seem to show any. This is possibly because the companion galaxy is too big or gas-poor for the jets to initiate visible galaxy-wide young star formation, the astronomers say.
