Image of active galactic nuclei detected by MeerKAT radio telescope. Credit: MALS team

With data collected through the MeerKAT radio telescope in South Africa, astronomers have identified many active galactic nuclei (AGN), which are active supermassive black holes at the centre of galaxies, and among the brightest objects in the universe.

Scientists at Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, India, who led the MeerKAT Absorption Line Survey (MALS), published a catalogue of radio sources — the survey’s first data release.

MALS aims to map cold gas (molecular and atomic hydrogen) associated with galaxies using absorption lines, to improve the understanding of star formation from galaxies and their evolution.

AGN emit winds and jets and become active when gas falls towards it, releasing large amounts of energy. “Cold gas is a key player in AGN activity and star formation. We will analyse the spectrum of these radio sources which encode signatures of cold gas in galaxies," says Neeraj Gupta, MALS's principal investigator. The team will also look for gas that may flow out from the AGN feedback or infall to fuel the black hole.

The 2020-2021 survey generated 500 TB of data which were shipped to IUCAA in tapes. The team, including PhD student, Partha Pratim Deka, then processed the deluge of data using an automated pipeline built at IUCAA.