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.<\/p>\n
The finding adds to growing evidence that the early universe was more evolved than previously assumed, they said.<\/p>\n
Named \u2018Alaknanda\u2019 after a Himalayan river, the grand-design spiral galaxy challenges existing theories on how early complex galactic structures formed, the researchers said.<\/p>\n
\u201cFinding 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,\u201d one of the researchers said.<\/p>\n
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 \u2018Astronomy & Astrophysics\u2019.<\/p>\n
Using NASA\u2019s 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.<\/p>\n
\u201cAlaknanda lies at a redshift of about 4, meaning its light has travelled more than 12 billion years to reach Earth,\u201d Jain said.<\/p>\n
\u201cWe 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,\u201d she said.<\/p>\n
Using JWST\u2019s infrared sensitivity and resolution, the team found that Alaknanda contains roughly \u201c10 billion times the mass of the sun in stars\u201d and is forming new stars at about 63 solar masses per year, nearly 20 to 30 times the Milky Way\u2019s current rate, the researchers said in a release.<\/p>\n
Before JWST, astronomers believed early galaxies were chaotic and clumpy, with stable spiral structures emerging only after several billion years, they said.<\/p>\n
Dominant models suggested that early galaxies were too \u201chot\u201d and turbulent to form ordered disks capable of sustaining spiral arms, the release said.<\/p>\n
\u201cAlaknanda tells a different story,\u201d Wadadekar said. \u201cThis 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\u2019s incredibly rapid by cosmic standards,\u201d he said.<\/p>\n
The discovery adds to growing JWST evidence that the early universe was more evolved than previously assumed.<\/p>\n
\u201cWhile 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,\u201d the release said.<\/p>\n
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.<\/p>\n
\u201cJust 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,\u201d she said.<\/p>\n
Although Alaknanda\u2019s photometric redshift is well-established, follow-up observations with JWST\u2019s NIRSpec instrument or the Atacama Large Millimeter\/submillimeter Array (ALMA) are required to measure its disk rotation, the researchers said.<\/p>\n
\u201cThese measurements will reveal whether the galaxy\u2019s disk is \u2018cold\u2019 and orderly or \u2018hot\u2019 and turbulent, helping scientists understand how its spiral arms formed,\u201d they added.<\/p>\n","protected":false},"excerpt":{"rendered":"Two researchers from an astrophysics institute in Pune have discovered one of the most distant spiral galaxies ever…\n","protected":false},"author":2,"featured_media":165501,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[108147,111,139,69,147],"class_list":{"0":"post-165500","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-alaknanda","9":"tag-new-zealand","10":"tag-newzealand","11":"tag-nz","12":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/165500","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=165500"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/165500\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/165501"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=165500"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=165500"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=165500"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}