Indian scientists have successfully detected and studied an Intermediate-Mass Black Hole (IMBH) located in the faint galaxy NGC 4395, about 4.3 million light-years away.

Key Highlights of Discovery

• The discovery was made by Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute of the Department of Science and Technology (DST).
• Features of the Black Hole
• • The intermediate-mass black hole (IMBH) discovered has a mass of approximately 22,000 times that of the Sun, making it one of the most precisely measured IMBHs.
  • Gas clouds were found orbiting the IMBH at a distance of 125 light-minutes (2.25 billion km) with a velocity dispersion of 545 km/s.
  • The black hole is accreting matter at just 6% of its theoretical maximum rate, indicating a faint but active galactic nucleus.
• Instruments Used: Observations were conducted using the 3.6-metre Devasthal Optical Telescope (DOT) and the 1.3-metre Devasthal Fast Optical Telescope (DFOT), equipped with the Aryabhatta Devasthal Faint Object Spectrograph and Camera (ADFOSC), an indigenously developed system for photometry and spectroscopy.
• Technique Applied: The team employed spectrophotometric reverberation mapping to calculate the time delay between emissions, helping determine the black hole’s mass.

What are IMBHs?

• Intermediate-Mass Black Holes are black holes that lie between stellar-mass black holes (a few solar masses) and supermassive black holes (millions to billions of solar masses).
• IMBHs are expected to have masses ranging from 100 to 100,000 times the mass of the Sun.

Why IMBHs are Difficult to Observe

• IMBHs are often found in faint, low-luminosity galaxies, making them hard to detect.
• Unlike supermassive black holes, IMBHs typically do not emit bright radiation unless they are actively accreting matter, which further complicates their observation.

Significance of Studying IMBHs

• IMBHs are believed to be the seeds of supermassive black holes, playing a crucial role in the evolution of galaxies and black hole formation.
• Finding and measuring more IMBHs is vital for filling the missing link in the black hole mass spectrum and for understanding how massive black holes grow over cosmic time.