Pune researchers find massive, grand-design spiral galaxy existing since universe's infancy
Pune (PTI): Two researchers from an astrophysics institute in Pune have discovered one of the most distant spiral galaxies ever observed - a massive, well-formed system that existed when the universe was just 1.5 billion years old.
The finding adds to growing evidence that the early universe was more evolved than previously assumed, they said.
Named 'Alaknanda' after a Himalayan river, the grand-design spiral galaxy challenges existing theories on how early complex galactic structures formed, the researchers said.
"Finding such a well-formed spiral galaxy at this early epoch is quite unexpected. It shows that sophisticated structures were being built much earlier than we thought possible," one of the researchers said.
Despite being present when the universe was only 10 per cent of its current age, Alaknanda appears strikingly similar to the Milky Way. The findings have been published in the European journal 'Astronomy & Astrophysics'.
Using NASA's James Webb Space Telescope (JWST), researchers Rashi Jain and Yogesh Wadadekar from the Pune-based National Centre for Radio Astrophysics (NCRA-TIFR) identified the galaxy.
"Alaknanda lies at a redshift of about 4, meaning its light has travelled more than 12 billion years to reach Earth," Jain said.
"We are seeing this galaxy as it appeared just 1.5 billion years after the Big Bang. Finding such a well-formed spiral galaxy at this early epoch is quite unexpected. It shows that sophisticated structures were being built much earlier than we thought possible," she said.
Using JWST's infrared sensitivity and resolution, the team found that Alaknanda contains roughly "10 billion times the mass of the sun in stars" and is forming new stars at about 63 solar masses per year, nearly 20 to 30 times the Milky Way's current rate, the researchers said in a release.
Before JWST, astronomers believed early galaxies were chaotic and clumpy, with stable spiral structures emerging only after several billion years, they said.
Dominant models suggested that early galaxies were too "hot" and turbulent to form ordered disks capable of sustaining spiral arms, the release said.
"Alaknanda tells a different story," Wadadekar said. "This galaxy had to assemble 10 billion solar masses of stars and build a large disk with spiral arms in just a few hundred million years. That's incredibly rapid by cosmic standards," he said.
The discovery adds to growing JWST evidence that the early universe was more evolved than previously assumed. "While other disk galaxies have been spotted at similar distances, Alaknanda is among the clearest examples of a spiral galaxy with well-defined arms at such a high redshift," the release said.
Jain said the team chose the name Alaknanda - one of the two main headstreams of the river Ganga - because of its connection to the Milky Way.
"Just as the Alaknanda is the sister river of the Mandakini, which is the Hindi name for our own Milky Way, we thought it fitting to name this distant spiral galaxy after the Alaknanda river," she said.
Although Alaknanda's photometric redshift is well-established, follow-up observations with JWST's NIRSpec instrument or the Atacama Large Millimeter/submillimeter Array (ALMA) are needed to measure its disk rotation, the researchers said.
"These measurements will reveal whether the galaxy's disk is 'cold' and orderly or 'hot' and turbulent, helping scientists understand how its spiral arms formed," they added.
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T20 WC star Samson named ICC Men's Player of the Month for March
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Dubai (PTI): India opener Sanju Samson was on Tuesday named ICC Men's Player of the Month for March, capping a stellar run that saw him play a defining role in the team's triumphant T20 World Cup campaign.
Samson did not get to play in the early part of the tournament but was the standout performer in the big games towards the end and helped India retain the title.
His latest honour also extends a unique streak, with players from different countries winning the award over the past five months including South Africa's Simon Harmer, Australia's Mitchell Starc, New Zealand's Daryl Mitchell and Pakistan's Sahibzada Farhan.
"Winning the ICC Player of the Month award is an incredible feeling, especially as it comes during what has been the most unforgettable phase of my cricketing journey. Playing a part in India's triumph at the Men's T20 World Cup was truly a dream realised, and it took some time for the magnitude of that moment to fully sink in," Samson said.
"This is an exciting era for Indian cricket, with immense talent across the board. I feel grateful for the opportunities I've received, and for the trust and support from my team-mates and coaching staff that have allowed me to perform at my best."
Not a regular part of the playing XI in the initial stages of the tournament, Samson was eventually called up for India's must-win Super 8 fixtures. After starting off with 24 against Zimbabwe, he picked form and didn't look back.
The opener missed out on a century against the West Indies by just three runs, but his attacking 97 not out set up India's spot in the semifinal.
A blistering 89 against England at the Wankhede helped India to 253 for 7, and the target proved elusive for the English who missed out by seven runs on March 5.
An equally amazing 89 was churned out during India's successful title defence in Ahmedabad, securing a 96-run win.
In the three crucial T20Is he was a part of in March, Samson notched up 275 runs at an astonishing average of 137.50 and a stunning strike rate of 199.27.
This is the first time that Samson has secured an ICC Men's Player of the Month honour.
New Zealand captain Melie Kerr won the women's honour for the third time, after an outstanding series against Zimbabwe and South Africa.
Taking over the white-ball teams from Sophie Devine, Kerr's captaincy seemed to have brought out the best in her with both the ball and the bat. In the Zimbabwe ODI series, she managed to snap 16 wickets in just three matches, including her career-best figures of 7/34.
Additionally, she also contributed with the bat, being the third highest run-scorer in the ODIs, scoring 140 runs across three games with an average of 46.67 in the counting month.
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