Right in the centre of galaxies lie the most intriguing yet mysterious cosmic features: the supermassive black holes (SMBH)! They have masses ranging from one million to 10 billion solar masses and puzzle astronomers’ work a lot.
However, some SMBH are less scarier, especially if they reach a bright phase. That phenomenon is known as active galactic nuclei (AGN), and it means that an SMBH will soon burn out. But when exactly?
A recent discovery of a dying SMBH might shed some light on that question.
Here is what you need to know.
A Dying SMBH Could Hold Huge Secrets
For Kohei Ichikawa and his research team from Tohoku University, finding when an SMBH might actually die is no longer a secret. They found by accident a dying AGN after detecting an AGN signal from the Arp 187 galaxy.
How they did it
The team examined radio images in the Arp 187 galaxy using two significant astronomy observatories, the VLA (the Very Large Array) and ALMA (the Atacama Large Millimeter/submillimeter Array). They succeeded in detecting a jet lobe, something familiar for an AGN, but there was a catch.
Researchers couldn’t identify a signal from the nucleus. What does this mean?
The AGN activity might be dead already.
“We used the NASA NuSTAR X-ray satellite, the best tool to observe current AGN acitvity,” explains Ichikawa.
More details about the discovery
The team also discovered that all the small scale AGN indicators are actually silent. The large ones, however, were bright. The reason?
Apparently, the AGN has recently been dampened within the last 3,000 years. So, AGNs could die within a 3,000-year time scale. During such a period, the nucleus would become 1000 times fainter.
These findings are genuinely intriguing, and we’re now closer to unveiling more secrets about SMBHs. The team will continue to work, searching for more dying AGN using the same technique.