November 2024

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 taikonauts Ye Guangfu, Li Cong, and Li Guangsu after the end of the Shenzhou 18 mission (Photo courtesy Xinhua/Li Xin)

It was night in China when the three Chinese taikonauts of the Shenzhou 18 mission returned to Earth after spending a little more than six months on the Chinese space station Tiangong, where they arrived on April 25. The three taikonauts Ye Guangfu, Li Cong, and Li Guangsu had left the station about nine hours earlier to land at a site called Dongfeng in China’s Inner Mongolia Autonomous Region. It’s a procedure that significantly reduces the time to return to Earth and now has become routine.