Astronomers spot 12 new quasars that can tell rate of expansion of universe, what are quasars? Explained

A group of astronomers at the European Space Agency have discovered 12 new quasars that have been warped by a naturally occurring cosmic ‘lens’ and split into four similar images.

12 rare Einstein crosses have been discovered with @ESAGaia!

The light of these #quasars is so strongly deflected by foreground galaxies that they are each visible as four distinct images.

They can help determine the expansion rate of the Universe 👉
https://t.co/IVeDsQ7Fr7 pic.twitter.com/R3uWM5NQNS

— ESA Science (@esascience) April 7, 2021

These newly discovered quasars are a rare phenomenon in our universe, so far 50 such quasars have been spotted since 1985. The recent discovery increases the number of discovered quasars so far by about 25 per cent.

The European Space Agency’s star mapping Gaia has been instrumental in discovering these 12 new quasars as it can survey the galaxy with high spatial resolution imaging to reveal the formation, composition, and evolution of the Galaxy.

What are Quasars?

Quasars, Quasi Stellar Radio Sources, are highly luminous cores of distant galaxies that are powered by supermassive black holes. They can give insight into determining the expansion rate of the universe and discover other mysteries also.

Quadruply-imaged quasars, like those found by @ESAGaia, are unique tools to learn more about dark matter and the expansion rate of the Universe 👉https://t.co/IVeDsQ7Fr7

Image credit: R. Hurt (IPAC/Caltech)/The GraL Collaboration pic.twitter.com/ketC10OLGR

— ESA Science (@esascience) April 8, 2021

Caption: The image in the tweet above explains how quadruply imaged quasars, or quads for short, are produced on the sky.

Quasars are visible as four distinct images called quadruply-imaged quasars. This is also referred to as ‘Einstein Cross’.

As explained by the Department of Science and Technology (DST), the gravity pull of a massive galaxy in the forefront of a quasar leads to the deflection of light of a quasar thus a quasar is visible as four distinct images.

The first quadruple image was found in 1985.

There has been a study demonstrating the power of machine learning to help astronomers in discovering more quasars. The study was led by the Gaia Gravitational Lenses Working Group (GraL) of astronomers, which comprises scientists from Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, an institute of Department of Science and Technology.

The study was published in ‘The Astrophysical Journal’.

Daniel Stern, the lead author of the study and a research scientist at the Jet Propulsion Lab USA referred to quasars as gold mines to all sorts of questions relating to dark matter, quasars ‘central engines’, and other mysteries of the universe.

About ESA

ESA is the European Space Agency that was established in 1975 with headquarters in Paris.

Gaia Gravitational Lenses Working Group (GraL)is a collaborative project with members from Australia, Brazil, Belgium, France, Germany, India Portugal, Switzerland, and the USA.