Context
Analysis of light of a gamma-ray burst,which dates back three billion years ago, has revealed the presence of a previously undetected black hole.
About the finding
- Intermediate-mass black holes: The discovered black hole is Intermediate-mass black holes which is an elusive category of black holes that was considered non-existing until a few years ago.
- In 2020, the Hubble Space Telescopeprovided a piece of evidence for an IMBH.
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Intermediate-mass black holes (IMBHs) are a class of a black hole with a mass approximately 100 to 100,000 times that of the Sun.
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The technique used
- The gravitational lensing technique was used to detect the black hole.
- Under this technique, the gravity around a massive body bends lightwhich comes from a source behind.
- It is then used to identify the intermediate-mass black hole (IMBH) which lensed the gamma-ray burst.
What is a gamma-ray burst?
- The gamma-ray burst that is known as GRB 950830 was detected in 1995.
- GRBs are the most energetic form of electromagnetic events in the universe having short bursts of gamma rays that ejected at the speed of light.
- Gamma-ray bursts are formed when a high-mass star collapses and creates a neutron star or black hole. ?
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What is Gravitational lensing?
- When the light from distant galaxies or events like gamma-ray bursts passes by massive objects in the universe such as stars or black holes then Gravitational lensing is expected to occur.
- The gravitational tug of these massive bodies can bend the light and causes the source to look distorted.
- Weak: Whengravitational lensing is weak, it distorts the distant object or galaxy to appear magnified or stretched out.
- Strong: When it is strong, it bends light to such a degree that multiple images of the same galaxy are visible.
Blackhole and its subtypes
- A black hole is a region of space-timewhere gravity is extremely strong that no object can escape from it.
- Types: There are two types of black holes which become three with the discovery:
- Stellar-mass black holes: These are the black holes witha mass of fewer than 100 times that of the Sun.
- Supermassive black holes (SMBH): These are the ones with a mass greater than 100,000 times that of the Sun.
Both stellar black holes and SMBHs are commonly found.
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Some of the discovered black holes
- The first-ever black hole detected was Cygnus X-1 in 1964.
- The closest black holeto Earth is a part of the system HR 6819 and is active just 1,000 light-years from earth
- The smallest known black hole is GRO J0422+32. It was discovered in 1992 at around 7,800 light-years from us.
- A supermassive black hole called Sgr A* and is 26,000 light-years from Earth. It holds a mass of at least 40 lakh times the Sun’s.
