Relativistic Jet May Provide Missing Link for Intermediate-Mass Black Holes

• Astronomers detected AT2019ijn, a rare transient event in a dwarf galaxy 3.4 billion light-years away, caused by an intermediate-mass black hole (IMBH) consuming a star.
• The discovery helps address the "missing link" in black hole classifications by providing evidence for IMBHs, which range from 100 to 100,000 Solar masses.
• Research indicates the event produced a relativistic jet, offering a new observational method for locating hidden black holes.

The Discovery and Process

• The event was initially identified as a fast-evolving blue optical transient (FBOT), appearing as a bright blue flash.
• Radio emissions continued to increase for two years before fading over four years, suggesting a jet moving at a significant fraction of the speed of light.
• The jet's orientation, perpendicular to Earth's line of sight, caused the delayed detection of the powerful radio flare.

Methodological Approach

• The research team utilized data from multiple international facilities:
  • NSF’s Karl G. Jansky Very Large Array (VLA).
  • The Very Large Array Sky Survey (VLASS).
  • Australian Square Kilometer Array Pathfinder (ASKAP).
  • Upgraded Giant Metrewave Radio Telescope (GMRT) in India.

Implications for Astronomy

• Identifying similar events may reveal how IMBHs form, evolve, and consume stellar matter.
• Many unusual optical transients may be members of this broader class of black-hole-powered events, previously overlooked due to delayed radio peaks.
• Future high-cadence sky surveys combining optical and radio data are expected to uncover additional candidates for study.