Scientists studying the early Universe have uncovered an intriguing mystery and as a closet Sherlock Holmes fan I cannot resist a mystery. Our mystery begins during the period of reionization when neutral hydrogen fog pervading the Universe gradually cleared to allow light to travel freely. A galaxy called JADES-GS-z13-1, observed just 330 million years after the Big Bang, has challenged existing theories by showing bright hydrogen emissions that should have been absorbed by the cosmic fog. This suggests that the cosmic fog may have cleared earlier than first thought.
James Webb Space Telescope NIRSpec spectra of four high-redshift galaxies including JADES-GS-z13-0 (Credit : NASA/ESA)
The team led by Joris Witstok published their findings in Nature where the James Webb Space Telescope (JWST) has been instrumental in their study. Using its advanced infrared capabilities, the telescope detected bright hydrogen emissions from this ancient galaxy, a galaxy whose redshift study not only revealed its extreme distance but some other properties where observed that have lead the team to review theories about the transmission of light and galaxy formation in the early Universe.
Determining the age of galaxy JADES-GS-z13-1 was key to their study and, by utilising JWST’s NIRCam imaging and NIRSpec instrument, they were able to verify the galaxy’s redshift at 13.0, putting its existence just 330 million years after the Big Bang. During their study however, an extraordinary bright Lyman-alpha hydrogen emission was observed that was far more intense than had previously believed possible during such an early stage of the evolution of the Universe.
.jpg)
NIRCam being installed in 2014 (Credit : NASA/Goddard/Chris Gunn)
During the era of reionization, the early universe was thought to be enveloped in a dense neutral hydrogen fog that effectively blocked the transmission of energetic ultraviolet radiation from galaxies. The unexpected detection of Lyman-alpha radiation from a galaxy at such an early stage was a surprise to the team; Kevin Hainline from the University of Arizona described it “We could think of the early universe as shrouded with a thick fog that would make it exceedingly difficult to find even powerful lighthouses peeking through, yet here we see the beam of light from this galaxy piercing the veil. This fascinating emission line has huge ramifications for how and when the universe reionized.”
The discovery has the team rather perplexed but there are two primary theories emerging. Witstok suggests the radiation could originate from a unique population of early stars – extraordinarily massive, hot, and luminous compared to later stellar generations, potentially representing the first stars in the Universe. Alternatively, the team proposes that a powerful active galactic nucleus driven by one of the first supermassive black holes might be responsible for creating the large bubble of ionized hydrogen surrounding the galaxy. For now, additional studies and observations are required before the mystery can be revealed.
Source : NASA’s Webb Sees Galaxy Mysteriously Clearing Fog of Early Universe