Galaxies

The ultramassive galaxies S1, S2, and S3

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.

Protogalaxies as seen by the James Webb Space Telescope (Image NASA)

An article published in “The Astrophysical Journal” reports some predictions offered by MOND (Modified Newtonian Dynamics), a theory based on modifications to Newton and Einstein’s gravitational laws that doesn’t include the existence of dark matter. Stacy S. McGaugh, James M. Schombert, Federico Lelli, and Jay Franck have applied this model to primordial galaxies studied with the James Webb Space Telescope obtaining a better agreement than the lambda-CDM model, the best cosmological model based on the existence of dark matter. This is one of the studies, often based on Webb’s observations, that are testing cosmological models that weren’t considered very much due to the lack of confirmation.

Artist's concept of a primordial dwarf galaxy with a fast growing supermassive black hole (Image NOIRLab/NSF/AURA/J. da Silva/M. Zamani)

An article published in the journal “Nature Astronomy” reports the results of the study of the dwarf galaxy cataloged as LID-568, which has at its center a supermassive black hole that is devouring materials at a rate that is more than 40 times faster than its theoretical limits. A team of researchers led by astronomer Hyewon Suh of the International Gemini Observatory/NSF NOIRLab combined observations conducted with the Chandra and James Webb space telescopes to obtain precise data on this voracious supermassive black hole. We see it as it was about 1.5 billion years after the Big Bang and its discovery indicates a way in which these very extreme objects manage to grow so quickly.

The galaxy NGC 1386

An article published in the journal “Monthly Notices of the Royal Astronomical Society” reports a study of the galaxy NGC 1386 that shows that star formation processes are taking place in its central regions despite the fact that it contains mostly old stars. A team of researchers led by astronomer Almudena Prieto of the Instituto de Astrofísica de Canarias in Spain combined observations conducted in visible light and near-infrared with ESO’s VST and in radio waves with the ALMA radio telescope to study those processes that are bringing about a sort of rejuvenation within NGC 1386.

The star cluster NGC 602 (Image ESA/Webb, NASA & CSA, P. Zeidler, E. Sabbi, A. Nota, M. Zamani (ESA/Webb))

An article published in “The Astrophysical Journal” reports the identification of 64 brown dwarf candidates in the star cluster NGC 602 in the Small Magellanic Cloud, one of the Milky Way’s satellite galaxies. A team of researchers used the James Webb Space Telescope to obtain the sensitivity and resolution needed to detect possible objects halfway between the planet and the star about 200,000 light-years away. Follow-up studies are needed to verify these candidates, the first brown dwarfs to be verified outside the Milky Way. NGC 602 is poor in elements heavier than hydrogen and helium, a condition that was normal when the universe was young, further reason for interest in studying the processes within the cluster.