An article published in the journal “Nature” reports the discovery of three ultramassive galaxies in the early universe in which stars are forming with an efficiency almost twice that of galaxies of average mass by the standards of that era. A team of researchers coordinated by the University of Geneva (UNIGE) used observations conducted with the James Webb space telescope within the FRESCO program. The three galaxies (Image NASA/CSA/ESA, M. Xiao & P. A. Oesch (University of Geneva), G. Brammer (Niels Bohr Institute), Dawn JWST Archive), which were cataloged as S1, S2, and S3, are almost as massive as the Milky Way and add to others that were discovered in recent years and are difficult to explain with the most accepted cosmological models, starting with lambda-CDM.
The FRESCO (First Reionization Epoch Spectroscopically Complete Observations) program aims to study galaxies we see as they were in the first billion years of the life of the universe. They’re galaxies characterized by strong emission lines in their spectra, and this allows the James Webb Space Telescope’s NIRCam (Near Infrared Camera) instrument to be used with excellent results to obtain spectroscopic analyses. Among other things, this helps to accurately estimate the distance of those galaxies.
This study of 36 galaxies included in the FRESCO program offers for most of them a good agreement with the lambda-CDM model, which at the moment is the cosmological model that gives the best agreement with various cosmological phenomena. The problem comes from the three ultramassive galaxies S1, S2, and S3, which have an efficiency in star formation decidedly out of the ordinary. They have a high dust content that gives them a reddish color in the images, and for this reason, they were nicknamed the Red Monsters.
According to the lambda-CDM model, galaxies should form slowly within dark matter halos. Normally, up to 20% of the gas present in these new galaxies goes to form stars. In the Red Monsters, about 50% of the gas goes to form stars.
This anomaly isn’t the first found in astronomical studies in recent years and the James Webb Space Telescope is discovering several primordial galaxies more massive and evolved than those predicted by the lambda-CDM model. Other researchers are finding some confirmation of the model based on modifications to the laws of gravity and doesn’t include the presence of dark matter but these results are still too limited to replace the most accepted models.
These results indicate that at best, the current cosmological models still need refinement. The James Webb Space Telescope is bringing interesting and sometimes surprising results but something is still missing to have a consistent model that fully describes the various cosmological phenomena. Studies continue using new observations conducted with the James Webb Space Telescope and other instruments capable of detecting primordial galaxies. In the coming years, astronomers will also use new instruments that will come into service to try to solve the mysteries of the universe.
