Awakening of Ansky: Mysterious X‑ray bursts from Virgo's heart
At approximately 580 million miles from Earth, in the centre of the galaxy SDSS1335+0728 in the constellation Virgo, an event surprised scientists worldwide. A supermassive black hole, inactive for years, suddenly began to emit intense bursts of X-ray radiation.
Although almost every galaxy has a black hole at its centre, most remain invisible to our instruments - dormant, silent, hidden. That was the case with the black hole in SDSS1335+0728 until 2019, when the first signs of its "awakening" were recorded.
According to National Geographic, observations from the XMM-Newton, Swift, NICER, and Chandra telescopes have confirmed the emission of strong, recurring X-ray pulses since February 2024.
What was recorded are so-called quasiperiodic eruptions (QPE), which are highly intense but short-lived radiation bursts that appear at almost regular intervals.
And this is the first time we have observed such an event in a black hole that seems to be waking up – says Lorena Hernández-García, an astronomer from the University of Valparaíso in Chile, who leads the team studying the phenomenon.
Ansky – the mysterious core of activity
The newly awakened centre of the galaxy has been nicknamed Ansky. The bursts from this object are significantly different from previously known QPEs—they are ten times brighter and last ten times longer than similar phenomena observed earlier.
The bursts of X-rays from Ansky are ten times longer and ten times more luminous than what we see from a typical QPE – emphasizes Joheen Chakraborty from MIT.
Riddles of the cosmic mechanism
As reported by National Geographic, scientists are trying to answer the question: What exactly causes these eruptions? One theory suggests a small object—perhaps a neutron star or smaller black hole—that regularly disrupts the matter in the accretion disk surrounding the supermassive black hole.
Another hypothesis suggests that the gas gathering around is rapidly heated and releases bursts of energy.
X-ray observations and the future of research
The XMM-Newton telescope, operated by the European Space Agency (ESA), played a key role in studying this phenomenon. Its exceptional sensitivity allowed it to capture even the weakest signals between the bursts, enabling precise calculation of the energy released by Ansky.
The new data may also impact future observations of gravitational waves.
These repetitive bursts are also likely associated with gravitational waves that ESA’s future mission LISA might be able to catch – added Chakraborty.
A step towards understanding black holes
Although black holes have fascinated scientists and the public for decades, many mysteries remain unexplored. The team of Hernández-García emphasises that the case of SDSS1335+0728 might completely change our understanding of how black holes "awaken" and how their accretion disks function.
Research continues, and the team hopes that further observations will shed more light on the QPE phenomenon, perhaps bringing us closer to understanding the most extreme objects in the Universe.
