At higher redshift, only Simba and OBELISK produce galaxies as massive as are found in JADES. The galaxy number density implied by the JADES galaxies at z ~ 10 is consistent with both the simulations and past observations. The most massive JADES galaxies have somewhat lower SFRs than simulated galaxies at z ~ 10, but lie within the scatter of the simulations. "In general, we find that each of these simulations produces galaxies with comparable stellar masses to the JADES galaxies by z ~ 10. I note here the conclusion of the paper. But the exaggerated claims made from the early Webb data aren't enough to worry about yet. In science, it's always important to keep an open mind. Astronomers may yet confirm the distance to a very large galaxy in the early universe that may force us to rethink our understanding of galaxy formation, and maybe even the ΛCDM cosmological model. The appearance of galaxies with 10^8 solar masses in the early universe was no sweat for ΛCDM, the team explained in their research paper, which has been submitted to The Astrophysical Journal Letters and is available as a preprint via arXiv.Īs usual, this isn't the final answer. If no models could generate galaxies of that mass at that age, then ΛCDM would be in trouble. The simulations allowed the researchers to play around with many kinds of models. 12 amazing James Webb Space Telescope discoveries of 2022 8 ways the James Webb Space Telescope is already revolutionizing astronomy The James Webb Space Telescope is revealing the earliest galaxies of the universe like never before, scientists say So the question then became, does ΛCDM allow for these smaller galaxies to exist at such a young age in the history of the universe, or does the tension remain? However, these galaxies had much smaller masses: around 10^8 and 10^9 solar masses. All those galaxies were just as distant as the previously identified galaxies, but they had confirmed, reliable distances. Using this more accurate technique, the team found a sample of four galaxies. This technique identifies the spectral lines of known elements emitted by the galaxies and uses them to measure the redshift, and thereby the distance, to the galaxies. To accurately judge if the Big Bang is in trouble, a new team of researchers used Webb to identify galaxies with a much more precise and reliable method of determining distance, known as spectroscopic redshift. That method is notoriously unreliable, with simple effects - like excess dust surrounding the galaxies - making them appear more distant than they really are. For the record-breaking galaxies that could be tension with cosmological models, the researchers relied on something called a photometric redshift, which fits a rough light spectrum of a galaxy to a model to estimate a distance. At the extreme end, the researchers claimed that it might even be possible for no galaxy formation model within the ΛCDM framework to create such large galaxies so quickly.īut those claims hinged on measuring a precise distance to those galaxies - an incredibly difficult task at these extreme distances. The researchers who discovered these galaxies estimated that their large masses put them in tension with many models of galactic formation and evolution. That is still much smaller than the Milky Way, but for the early universe, they are quite gigantic. Several were quite large - well over 10^10 solar masses. So what's the conflict, then? The apparent tension came about because of the estimated masses of those galaxies. In fact, one of the main goals of the Webb telescope was to discover and characterize those first galaxies, so finding galaxies in the incredibly young universe is a point in favor of the Big Bang theory, not against it. Over hundreds of millions of years, those pockets formed into the first stars, and eventually grew to become the first galaxies. But over time, those density differences grew, with the slightly denser pockets pulling more material onto them.
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