A previously dormant black hole located in the galaxy SDSS1335+0728, situated in the Virgo constellation around 300 million light years from Earth, is now emitting regular X-ray flares, according to a new study published in Nature Astronomy.
Astronomers began focusing on the galaxy after it started to exhibit unusual brightness in 2019. This change drew the attention of various observatories, though the significance was not immediately understood.
In February 2023, astronomers in Chile reported observing frequent X-ray bursts from the galaxy, which they interpreted as indications of the central black hole becoming active again after a long dormant period.
The central region of SDSS1335+0728 has been reclassified as an active galactic nucleus and has been nicknamed “Ansky” by researchers. It is now being closely studied using several X-ray telescopes.
The observed X-ray bursts—known as quasiperiodic eruptions (QPEs)—are significantly more intense and longer in duration than typically seen. These eruptions occur every 4.5 days, with each one lasting longer and being more luminous than standard QPEs.
While QPEs are often linked to black holes absorbing material from nearby stars, no evidence suggests a recent stellar disruption near Ansky. This has led scientists to explore alternative explanations, such as interactions between the black hole's accretion disk and passing objects.
Researchers, including those from the European Space Agency and MIT, emphasise that more data is necessary to refine models explaining these flares. Current theories remain speculative due to limited observations.