The international astronomers from the Gaia Gravitational Lenses Working Group (GraL) have discovered 12 rare quasars.
Context
The international astronomers from the Gaia Gravitational Lenses Working Group (GraL) have discovered 12 rare quasars.
About the rare quadruple quasars
- Quasars are distant galaxies with extremely luminous nuclei.
- Characteristics: They are consist of black holes.
- They measure many million times larger than our Sun.
- They are surrounded by thick gaseous matter.
- The first quadruple quasar image was captured in 1985.
- The latest finding has now increased the total confirmed Einstein’s crosses by 25 percent.
- Significance:Quasar observations are mainly used-
- to study dark matter in determining the evolution of galaxies
- to understand the rate of expansion of the universe., which is measured by using the Hubble-Lemaítre constant.
Hubble-Lemaítre constant
- It is expressed by the equation v = H0D, with H0 the constant of proportionality.
- Hubble constant is most frequently quoted in (km/s)/Mpc.
- Its value is about 70 (km/s)/Mpc.
- The SI unit of H0 is simply s−1, and the SI unit for the reciprocal of H0 is simply the second.
- The reciprocal of H0 is known as the Hubble time.
- The Hubble constant can also be interpreted as the relative rate of expansion.
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How the study is conducted for quasars?
- Each of the discovered quasars offersfour distinct quadruple images, which is commonly called Einstein’s cross.
- Gravity causes massive objects like galaxies and emissions from them to bend over time and space. Emissions from a quadruple quasar are said to bend over time and space causing ‘natural’ lenses.
- Some deflection is resultant of the presence of numerous galaxies which act as barriers located between a source and Earth, ultimately split it into four images.
- Big Data and Augmented Intelligence were applied to confirm this rare discovery.
How it is significant?
- Efforts are being conducted to confirm that the four closely packed images were not a pure chance alignment of four independent sources, but four images of a single, distant source, lensed by an intervening galaxy.
- This will help in refining the existing understanding of the universe’s rate of expansion and mysteries surrounding dark matter.
