Astronomers have used superior devices to calculate a extra correct age of Maisie’s galaxy, found by the James Webb Area Telescope (JWST) in June 2022. Though the star system isn’t fairly as previous as initially estimated, it’s nonetheless one of many oldest recorded, from 390 million years after the Massive Bang — making it about 13.4 billion years previous. That’s a mere 70 million years youthful than JADES-GS-z13-0, the (present) oldest-known system.
A workforce led by the College of Texas at Austin astronomer Steven Finkelstein found the system final summer time. (The title “Maisie’s galaxy” is an ode to his daughter as a result of they noticed it on her birthday.) The group initially estimated that it was solely 290 million years after the Massive Bang, however analyzing the galaxy with extra superior tools revealed it’s about 100 million years older than that. “The thrilling factor about Maisie’s galaxy is that it was one of many first distant galaxies recognized by JWST, and of that set, it’s the primary to really be spectroscopically confirmed,” mentioned Finkelstein.
The spectroscopic affirmation got here courtesy of the JWST’s Close to InfraRed Spectrograph (NIRSpec) performed by the Cosmic Evolution Early Launch Science Survey (CEERS). The NIRSpec “splits an object’s mild into many alternative slim frequencies to extra precisely determine its chemical make-up, warmth output, intrinsic brightness and relative movement.” Redshift — the motion of sunshine in direction of longer (redder) wavelengths to point movement away from the observer — held the important thing to extra correct courting than the unique photometry-based estimate. The superior instruments assigned a redshift of z=11.4 to Maisie’s galaxy, serving to the researchers decide on the revised estimate of 390 million years after the Massive Bang.
The astronomers additionally examined CEERS-93316, a galaxy initially estimated at 235 million years pre-Massive Bang — which might have made it astonishingly previous. After learning this technique, it revealed a redshift of z=4.9, which locations it at a mere one billion years after the Massive Bang. The primary defective estimate about CEERS-93316 was comprehensible: The galaxy emitted an uncommon quantity of sunshine in slim frequency bands related to oxygen and hydrogen, making it seem bluer than it was.
Finkelstein chalks up the miss to dangerous luck. “This was a form of bizarre case,” he mentioned. “Of the numerous tens of excessive redshift candidates which were noticed spectroscopically, that is the one occasion of the true redshift being a lot lower than our preliminary guess.” Finkelstein added, “It might have been actually difficult to clarify how the universe might create such a large galaxy so quickly. So, I believe this was in all probability all the time the almost definitely consequence, as a result of it was so excessive, so vivid, at such an obvious excessive redshift.”
The CEERS workforce is now evaluating about 10 extra programs that might be older than Maisie’s galaxy.
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