Black hole activities suppress the birth of new stars around it, shows a new study that can help in a deeper understanding of how galaxies evolve and may provide answers to why some have very low star-formation rates.
Supermassive black holes at the centres of galaxies are known to drive outflows of gas, and astronomers have long studied how feedback processes from these outflows can in turn determine the evolution of these galaxies. However, a key puzzle has been to understand the relative influence of this gas outflow versus radiation from the central regions on the behaviour and evolution of the host galaxy.
A new study led by astronomers at the Indian Institute of Astrophysics (IIA), an autonomous institute of Department of Science and Technology (DST) has uncovered key insights into these powerful forces shaping our Universe. Their study reveals that both the intense radiation from around the black holes, as well as the high-speed jets they emit, can work together to eject gas from the centers of galaxies, potentially shutting down star formation in their central regions and regulating galactic growth.
Using cutting-edge archival data from international astronomical facilities like the Sloan Digital Sky Survey (SDSS) Telescope at optical wavelengths and the Very Large Array (VLA) at radio wavelengths, both located in the United States, the researchers studied over 500 relatively nearby galaxies hosting active galactic nuclei (AGN). AGN are energetic galaxy centers that emit copious radiation and gas, powered by matter falling onto their supermassive black holes, many millions of times more massive than our Sun.
Payel Nandi, a Ph.D. student at IIA and the lead author of the study explains, “We found that outflows of warm ionized gas are widespread in AGN, and while radiation from the black hole is the main driver, galaxies with radio jets show significantly faster and more energetic outflows”.