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Goa PIO leads Nasa’s team to find the furthest group of galaxies. Indian News


PANAJI: An international team of Nasa-linked astronomers, led by a Goa-born scientist of Indian origin, Vithal Tilvi, has discovered a never-before-seen group of galaxies, now labeled EGS77, which is the furthest group of galaxies ever seen.

In 2013, Tilvi was also part of a team that discovered the farthest galaxy ever seen by astronomers. The new group of galaxies, EGS77, is estimated to be more than 13 billion light-years from Earth. It took Tilvi and the team four years to make the findings.

This group of galaxies can now help astronomers see the Universe directly in their infancy, and see what the chemicals present when the Universe had just been born.

“As we look further and further, we are looking back in time. This is because, the stellar light carrying information about the group of galaxies, is coming to Earth now, after traveling for 13 billion years,” Tilvi told TOI.

“It’s usually difficult to see galaxies up to EGS77 because of the presence of neutral hydrogen fog in the Universe, which blocks some of the galaxy’s light,” said James Rhoads of Nasa, a member of the team.

Fortunately, the intense heat of these same galaxies removes the surrounding hydrogen fog, allowing light from the galaxy to travel freely to Earth. Galaxies and the group of galaxies like EGS77 must have cleaned up all the hydrogen fog, leading to the transition from an opaque universe to a transparent universe that we see today.

“This is a tremendous achievement and our knowledge of how the Universe evolved,” Tilvi said.

The findings of the EGS77 discovery are first presented on January 5, at the Conference of the American Astronomical Society in Hawaii.

“While this is the first group of galaxies identified as responsible for cleaning up hydrogen fog, future Nasa missions will tell us much more,” said Sangeeta Malhotra at Nasa, co-author of the article “Onset of Cosmic Reionization: Evidence of An Ionized Bubble Merely 680 Myr (millions of years) after the Big Bang”.

In 2013, Tilvi was part of a team that discovered the most distant galaxy in the Universe and, in 2017, led a team of astronomers who discovered the first black hole candidate in the Universe.

He is currently the project leader for a Nasa-funded project to study this black hole using observations taken by the Hubble Space Telescope. Tilvi is also part of Nasa’s Wide Field Infrared Reconnaissance Telescope (WFIRST) team, which will be launched in 2025.

The distance of EGS77 from Earth means that it is at the very edge of what can be observed using the best current technology on a platform such as the Hubble Space Telescope.

“The current telescopes we have, like the Hubble Space Telescope, were not meant to discover galaxies that far. But we’re pushing the boundaries. In another year and a half, the James Webb Telescope, which is much larger than the Hubble Space Telescope, will be launched, and our plan is to use this new telescope to see groups like EGS77,” Tilvi said.

Tilvi is currently a visiting researcher at the School of Earth and Space Exploration at Arizona State University, USA, and is contributing to the Goa Government’s State Council of Higher Education as a professor of research, development innovation.

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