One of the earliest galaxies known in the Universe has recently been identified as a red blob lurking in the background of a deep view of space.
The object, known as Maisie’s Galaxy, was seen by the James Webb Space Telescope when it first appeared 390 million years after the Big Bang, according to spectroscopic study. Although it is not exactly as old as researchers first believed, it is now recognized as one of the oldest confirmed galaxies in the Universe.
The findings, according to a group led by astronomer Pablo Arrabal Haro of the US National Science Foundation’s NOIRLab, not only support the notion that the early Universe was significantly more populous than anticipated, but also highlight the need for caution when interpreting the JWST discoveries.
The galaxy was named in honor of Steven Finkelstein’s daughter Maisie, on whose birthday it was discovered last year. “The exciting thing about Maisie’s galaxy is that it was one of the first distant galaxies identified by JWST, and of that set, it’s the first actually to be spectroscopically confirmed,” he says.
It takes some thinking out to pinpoint the time period during which galaxies first appeared in the early Universe.
Redshift is currently our finest tool. Most far-off objects outside of our galaxy seem to be receding because the Universe is expanding at an increasing rate. The farther away the material is from us, the faster it appears to be departing from us.
Because of this, light is stretched, or redshifted; as a result, its wavelengths lengthen and attenuate out into the redder portions of the spectrum. Astronomers identify this phenomena with the letter Z and use redshift measurements to determine when the light was released.
The JWST is an effective tool for studying the Universe at these infrared wavelengths. Because of this, researchers are utilizing it to probe the early Universe more thoroughly than ever before.
However, there are other methods for calculating z. When Finkelstein and his team first wrote about Maisie’s Galaxy, they used photometry, or the brightness of the light viewed through various filters, to determine their redshift estimate. The estimate from that work was z12. They believed the galaxy was discovered at 366 million years after the Big Bang, so to speak.
The JWST’s spectroscopic instrument, NIRSpec, which divides the light into several near-infrared wavelengths for a more in-depth investigation, was then used to further improve that conclusion. And the redshift from the NIRSpec data was z=11.4, or roughly 390 million years after the Big Bang. This indicates that it took the JWST around 13.4 billion years to detect the light from Maisie’s Galaxy.
Two additional early Universe galaxies discovered by the Cosmic Evolution Early Release Science (CEERS) Survey, which also produced Maisie’s Galaxy, were examined in the study. One of them, with a redshift of z=11.043, confirmed the photometric redshift estimate, but the other was significantly off.
Spectroscopic follow-up was required to confirm the tentative identification of CEERS-93316, which was made at redshift z16.4 and 250 million years after the Big Bang. The redshift determined by spectroscopic follow-up was a significantly different z=4.9. 1.2 billion years have passed since the Big Bang at that point.
Its three overlapping characteristics, which resembled the colors anticipated of a galaxy discovered at z=16 in photometric research, led to the misidentification.
According to the astronomers, additional galaxies may fall into this “triple overlap zone,” necessitating extreme caution for any objects that appear to have particularly high redshifts.
But as far as CEER-93316 is concerned, everything works out in the end.
Finkelstein asserts that it would have been extremely difficult to explain how the Universe could have produced such a large galaxy so quickly.
As a result, I believe that this conclusion was always more possible due to the object’s great brightness and seeming high redshift.
The research has been published in Nature.
