A few notes from me to help clear up what I see in the report. https://www.nature.com/articles/s41586-020-2276-y
, "...The existence of such a massive, rotationally supported, cold disk galaxy when the Universe was only 1.5 billion years old favours formation through either cold-mode accretion or mergers, although its large rotational velocity and large content of cold gas remain challenging to reproduce with most numerical simulations7,8."
There are still problems in the computer simulations to explain such large, rotation velocities reported for a galaxy with z=4.2603 spinning at some 270 km/s. We have reports showing dark matter has problems with the Milky Way, dwarf galaxy counts in the computer simulations. 'Groupie' galaxies orbiting Milky Way tell us about dark matter, how galaxy formed
, "...Scientists have also extracted information about the halos of dark matter that surround these galaxies, as well as a prediction that our home galaxy should host an additional 100 or so very faint satellite galaxies awaiting discovery..."
My comment - *awaiting discovery*. We have another report out on DM too showing DM is entering a crisis phase now apparently. Milky Way Dark Matter Signals in Doubt after Controversial New Papers
, 'Existential Crisis' "We know it’s there, but we don’t know what it is: this invisible stuff is dark matter. Scientists are fairly certain it dominates the cosmos, yet its ingredients are unclear." Now there is the scalar DM model under review, Searching for scalar dark matter using compact mechanical resonators
"Researchers hypothesize that ultralight dark matter is extremely light, lighter even than neutrinos. If such dark matter particles existed, their density would be so large that they would be better viewed as a fluid that permeates the galaxy, producing a wavelike disturbance on normal matter. "The ultralight dark matter hypothesis is motivated by string-theory scenarios, and moreover, might explain some puzzling discrepancies between the predictions of more prosaic dark molecules and the distribution of dark matter on galactic scales," Daniel Grin, another researcher involved in the study, told Phys.org... Overall, the recent study carried out by Singh, Manley, Grin, Wilson and their colleagues highlights the potential of state-of-the-art mechanical systems at the cm-scale for detecting dark matter in previously unexplored regimes, with individual particle masses ranging from 10^-48 kg to 10^-42 kg. In the future, these resonators could thus play a crucial role in the search for dark matter, particularly that in the ultra-light regime."
My observation. It should be pointed out that without DM, the BB model fails to create structure in the universe as it expands, thus no galaxies, no stars, no planets. Computer simulations using any form of DM, are model dependent upon this critical input parameter to make the simulations work. Presently, clearly identifying what DM is (assuming it exists), remains challenging in cosmology. When I use my telescopes to study the Galilean moons moving around Jupiter, DM is not visible or altering their orbits at Jupiter