Astronomers have observed a rare and unprecedented event: the sudden awakening of a massive black hole at the center of the galaxy SDSS1335+0728. This galaxy, located 300 million light-years away in the constellation Virgo, had been calm and inactive until late 2019 when it suddenly began to shine much brighter. This unexpected change led scientists to investigate using data from various space and ground-based observatories, including the European Southern Observatory’s Very Large Telescope (ESO’s VLT).
In a study published in Astronomy & Astrophysics, the research team revealed that the galaxy’s core started showing dramatic brightness changes, indicating that the massive black hole at its center had become active. This phenomenon is classified as an “active galactic nucleus” (AGN), where the black hole begins to consume surrounding material, emitting immense energy.
The brightness variations have continued for over four years, a period far more extended than typical events like supernovae or tidal disruption events, which usually last only a few dozen to a few hundred days. The team used archival data and new observations to find that SDSS1335+0728 is now emitting significantly more light across ultraviolet, optical, and infrared wavelengths and X-rays.
This event marks the first time astronomers have observed the activation of a massive black hole in real-time, providing a unique opportunity to study the processes by which black holes grow and affect their host galaxies. The findings also raise the possibility of similar awakenings occurring in other galaxies, including our own Milky Way, although it is uncertain how likely this is to happen.
The research continues with follow-up observations to confirm the nature of the phenomenon, whether it’s an unusually slow tidal disruption event or a new kind of event altogether. The data collected is invaluable for understanding black hole behaviour and galaxy evolution.
