NASA's Hubble Space Telescope and Chandra X-ray Observatory have identified a potential intermediate-mass black hole (IMBH) in the galaxy NGC 6099. This object, designated NGC 6099 HLX-1, is located on the outskirts of the galaxy, approximately 40,000 light-years from its center. The discovery was announced on July 24, 2025.
IMBHs, which are theorized to have masses between a few hundred and a few hundred thousand times that of the Sun, are challenging to detect due to their relatively low luminosity compared to stellar-mass and supermassive black holes. They are often identified when they interact with nearby stars, leading to tidal disruption events that produce significant radiation.
Observations indicate that NGC 6099 HLX-1 has exhibited X-ray emissions with temperatures around 3 million degrees Celsius, consistent with the energy expected from a tidal disruption event. Additionally, Hubble's imaging has revealed a compact star cluster surrounding the black hole, suggesting a potential source of material for accretion.
The detection of NGC 6099 HLX-1 provides valuable insights into the formation and evolution of black holes, particularly in understanding the transition between stellar-mass and supermassive black holes. Ongoing monitoring and future observations are expected to shed more light on the characteristics and behavior of this elusive class of cosmic objects.