NEW DELHI: Astronomers have discovered a dozen quasars that have been broken into four identical images by a naturally occurring celestial “lens.” Quasars are supermassive black holes that fuel the incredibly bright centers of distant galaxies.
This rare find brings the total number of known quasars or quads up to around a quarter of a million, and it may help scientists figure out the universe’s expansion rate and other mysteries. Quasars with quadruple images are uncommon; the first quadruple image was discovered in 1985.
Astronomers have discovered about fifty of these “quadruply imaged quasars,” or quads, over the past four decades, which occur when the gravity of a large galaxy that sits in front of a quasar breaks its single image into four, according to the Department of Science and Technology (DST).
The analysis by the Gaia Gravitational Lenses Working Group (GraL) of astronomers, which included scientists from the DST’s Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, demonstrates the power of machine learning to aid astronomers in their quest for these celestial jewels. The study has been accepted for publication in ”The Astrophysical Journal”, the DST said. “The quads are gold mines for all sorts of questions. They can help determine the expansion rate of the universe and help address other mysteries, such as dark matter and quasar ”central engines”,” said Daniel Stern, lead author of the new study and a research scientist at the Jet Propulsion Laboratory USA.