Indian researchers Rashi Jain and Yogesh Wadadekar at NCRA-TIFR, Pune, discovered Alaknanda—a mature spiral galaxy resembling the Milky Way—using JWST data. Formed just 1.5 billion years after the Big Bang, 12 billion light-years away, it challenges theories on early galaxy formation with its grand spiral arms.
Discovery Details
Alaknanda, named after the Himalayan river feeding the Ganga, spans 30,000 light-years with about 10 billion solar masses and clear "grand design" spiral arms visible via gravitational lensing from Abell 2744 cluster. JWST's infrared imaging across 21 filters revealed its stellar mass, dust, and star-formation rate, showing surprising maturity when the universe was only 10% its current age.
This find, published in Astronomy & Astrophysics, suggests complex structures emerged far earlier than models predicted, prompting reevaluation of galaxy evolution.
Key Highlights
Ancient Timeline: Light traveled 12 billion years; galaxy active at redshift z~10, just 1.5 billion years post-Big Bang.
Milky Way Mirror: Symmetric spirals, "beads-on-a-string" star clusters; one-third Milky Way size but fully formed disk.
Tech Edge: JWST UNCOVER/MegaScience surveys amplified by lensing; GALFIT analysis confirmed structure.
Future Probes: ALMA/JWST spectroscopy to check disk dynamics—cold gas inflows or mergers?
Sources: India Today, Firstpost, Deccan Herald, BBC