A red spot hidden in the background of a deep space image has now been confirmed as one of the earliest known galaxies in the Universe. It’s called the Maisie Galaxy, and spectral analysis has confirmed that the James Webb Space Telescope observed the object as it appeared just 390 million years after the Big Bang. It wasn’t as early as scientists thought, but it’s now officially one of the first confirmed galaxies in the Universe. According to a team led by astronomer Pablo Arrabal Haro of the US National Science Foundation’s NOIRLab, the results not only help confirm that the early Universe was more populated than expected, but the analysis of observations JWST monitoring requires special attention. The author explains: “What’s interesting about the Maisie Galaxy is that it was one of the first distant galaxies identified by JWST, and in this set, it was the first galaxy that was actually confirmed spectroscopically. “. Austin, who named the galaxy after his daughter, on the birthday of the galaxy’s discovery last year. frameborder=”0″ allow=”accelerometer; automatic reading; clipboard-write; encrypted media; gyroscope; picture in picture; web-share” allowfullscreen> Determining the period of appearance of galaxies in the early Universe takes some time. The best tool we currently have is redshift. Because the Universe is expanding at an increasingly rapid rate, most of the distant objects in our galaxy appear to be receding. The farther light must travel to reach us, the faster distant matter seems to move away from us.
This results in stretched or redshifted light; its wavelength becomes longer, attenuating in the redder parts of the spectrum. Using the letter z to describe this phenomenon, astronomers use redshift measurements to determine how long the light takes. JWST is a powerful tool for studying the Universe in these infrared wavelengths. That’s why scientists are using it to look deeper into the early universe than we were able to do before. But there is more than one way to calculate z. When Finkelstein and his team first published the Maisie Galaxy, they based their estimates on the redshift on the photometric; i.e. the brightness of visible light through multiple filters. This work gave an estimate of z~12. This means they think the galaxy was observed around 366 million years after the Big Bang. To refine this result, the team then used JWST’s spectrometer, NIRSpec, which splits the light into different near-infrared wavelengths for more detailed analysis. And the NIRSpec data returns redshift z=11.4; about 390 million years after the Big Bang. This means that light from the Maisie galaxy traveled for about 13.4 billion years before being caught by JWST. The search also looked at two other galaxies from the early universe collected as part of the Cosmic Evolutionary Early Release Science (CEERS) survey that gave us the Maisie galaxy. One of them returns a redshift that matches its photometric estimate, with a redshift of z=11,043; but the other is pretty much extinct. CEERS field. These dots represent thousands of galaxies. (F. Summers, G. Bacon, J. DePasquale, L. Hustak, J. Olmsted, A. Pagan/STScI)CEERS-93316 was tentatively identified 250 million years after the Big Bang – redshift z≃16.4 – but spectral monitoring is needed for confirmation. And spectral tracking has a very different redshift, only z=4.9. That was about 1.2 billion years after the Big Bang.
The misidentification occurs because it has three overlapping properties that mimic the expected color of a galaxy detected at z≈16 in photometric analysis. Other galaxies may also fall into this “triple overlap,” the researchers say, requiring special attention for objects that appear to have particularly high redshifts. But, all ends well, as far as CEER-93316 is concerned. “It is difficult to explain how the Universe was able to create such a large galaxy so soon,” Finkelstein said. “So I think that’s probably still the most likely outcome, because it’s very bright, very bright, at such a high redshift.” The study was published in the journal Nature.
source:
https://www.nature.com/articles/s41586-023-06521-7