Massive disk galaxy could change our understanding of how galaxies are born

Some additional reports on this interesting, high redshift galaxy and the difficulty fitting into the BB model. https://phys.org/news/2020-05-alma-massive-rotating-disk-early.html
"Galaxy DLA0817g, nicknamed the Wolfe Disk after the late astronomer Arthur M. Wolfe, is the most distant rotating disk galaxy ever observed. The unparalleled power of ALMA made it possible to see this galaxy spinning at 170 miles (272 kilometers) per second, similar to our Milky Way."

I note that rotating at 272 km/s is similar to older reports for measuring the Sun's Local Standard of Rest (LSR) velocity in the Milky Way, A Large Local Rotational Speed for the Galaxy Found from Proper Motions: Implications for the Mass of the Milky Way
This is interesting. The massive rotating disk challenges BB cosmology model to explain how these galaxies formed so early in the BB model. I note the redshift or z = 4.2603 according to the link cited in the phys.org report: https://www.nature.com/articles/s41586-020-2276-y
"Abstract Massive disk galaxies like the Milky Way are expected to form at late times in traditional models of galaxy formation1,2, but recent numerical simulations suggest that such galaxies could form as early as a billion years after the Big Bang through the accretion of cold material and mergers3,4. Observationally, it has been difficult to identify disk galaxies in emission at high redshift5,6 in order to discern between competing models of galaxy formation. Here we report imaging, with a resolution of about 1.3 kiloparsecs, of the 158-micrometre emission line from singly ionized carbon, the far-infrared dust continuum and the near-ultraviolet continuum emission from a galaxy at a redshift of 4.2603, identified by detecting its absorption of quasar light. These observations show that the emission arises from gas inside a cold, dusty, rotating disk with a rotational velocity of about 272 kilometres per second. The detection of emission from carbon monoxide in the galaxy yields a molecular mass that is consistent with the estimate from the ionized carbon emission of about 72 billion solar masses. 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."

Using the cosmology calculators for the BB model, z = 4.2603 is 12.276E+9 light-time distance from Earth. The comoving radial distance is much farther away, http://www.astro.ucla.edu/~wright/CosmoCalc.html

The cold gas pathway, where the gas streams along the cosmic filaments without collisions, is interesting. Tiley is correct that this result is not robust but need repetition, but the method used implies this type of galaxy should be common - they had to use background quasar galaxies to observe early non-quasar galaxies by absorbed light, and they were only up to 6 found galaxy candidates when they found the Wolfe disk.

rod said:

"Galaxy DLA0817g, nicknamed the Wolfe Disk after the late astronomer Arthur M. Wolfe, is the most distant rotating disk galaxy ever observed. The unparalleled power of ALMA made it possible to see this galaxy spinning at 170 miles (272 kilometers) per second, similar to our Milky Way."

I don't know the distribution in galaxy rotation curves, but due to their similar formation histories - gas clouds streaming along galactic filaments - galaxy peculiar velocities (when expansion is accounted for) is much the same. It is a similar phenomena to stars withing Milky Way due to the rotation, relatively few stars are accelerated by gravitational sling shots.

The rotation of the disk is decided by the rotation of the about one order of magnitude more massive dark matter halo it is embedded in, but at the same radius - Wolfe disk ~ 10^11 stars, Milky Way ~ 10^(11-12) stars - I would then expect about the same rotational speed.

Apparently galaxy histories are constrained by the cosmic filament flow, so they start out with gas rotating with rotation axis parallel to the filament "narrow" axis and the rotation decided by the filament radius at a guess. Again, with rather narrow distribution of filament width follows narrow distribution of rotation. As the galaxies stream towards the filament nodes, and the filament narrows due to that mass redistribution and due to gravitational clumping within, they collide and rotation axis tips over to become perpendicular to the filament axis. IIRC Milky Way, which is relatively calm - it has seen mergers but has a moderate star formation rate and a moderately calm super massive black hole - is in between the two states (not tipped over vs tipped over). Assuming random collisions I would expect a slight broadening of the rotational distribution.

I think the problem here is to account for the cold gas pathway. But it has been done, I take it:

"Modern simulations of structure formation make use of supercomputers to follow dark matter and gas over billions of years after the big bang. In effect, they create a virtual universe, based on the known physical laws, that allows scientists to analyze all phases of cosmic evolution.

Two recent simulations, the smaller-scale Auriga simulation of Milky-Way-like galaxies and the large-scale detailed TNG50-Simulation, opened up the possibility of an alternative mode of formation: Already cold gas flowing into galaxies, following the filaments of the dark matter network, avoiding the collisions that would heat the gas up, allows for the formation of massive disk galaxies at much earlier times than the collision-and-cooling scenario."

https://www.mpg.de/14829540/they-grow-up-so-fast-new-observations-show-that-massive-disk-galaxies-formed-exceptionally-early-in-cosmic-history ]

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 :)

rod said:

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 :)

I don't know the cosmic simulations enough to know if they have problems with statistics - they may see large disks, but maybe not so early and/or soo frequently as the observations now imply - but I note that the order of discovery was the simulations discovered the cold-mode accretion before the observation. The galaxy and star studies is after all the new research edge after inflation as well as dark energy and dark matter has become the best theory out there http://www.sciencemag.org/news/2018/05/galaxy-simulations-are-last-matching-reality-and-producing-surprising-insights-cosmic ].

Perhaps the simulations' single biggest lesson so far is not that scientists need to revise their overarching theory of cosmology, but rather that problems lurk in their understanding of astrophysics at smaller scales. In particular, their theory of star formation comes up wanting, Springel says. To produce realistic galaxies, modelers must drastically reduce the rate at which clouds of gas form stars from what astrophysicists expect, he says. "Basically, the molecular clouds form stars 100 times slower than you'd think," he says.

Most likely, star formation flags because feedbacks from supernovae and supermassive black holes drive gas out of a galaxy. Unfortunately, those processes are far too small to resolve in the simulations. When modelers deposit the energy of a supernova in a larger grid element, not much happens: Instead of generating wind, the energy just radiates away. Similarly, researchers cannot simulate the fitful way that black holes feed on gas and radiate x-rays. To capture these key bits of astrophysics, modelers must rely on the ad hoc subgrid prescriptions that they tune by hand.

Simulators hope to replace such crude assumptions with models based more solidly on physics. To do that, they're hoping to enlist the help of astrophysicists working on much more finely resolved models that simulate the birth of stars from molecular clouds just a few light-years wide and even the evolution of individual stars. Those smaller-scale models are themselves works in progress. For example, astrophysicists modeling supernova explosions still struggle to make their virtual stellar time bombs go off.

Nevertheless, Eve Ostriker, an astrophysicist at Princeton University who models interstellar gas, says she's eager to help put galaxy simulations on a sounder footing. "My interest in this is to replace the tuning with some physics and say, ‘OK, this is what it is, no tuning allowed,’" she says. The hope is to string together results from different size scales in a way that minimizes the need for fudge factors, researchers say. "What you want is a picture that's coherently stitching together across the entire range of scales," Hopkins says.

Ultimately, through observations and simulations, some researchers still hope to develop a unified narrative that can explain how any galaxy gets its shape and properties. Taking an extreme position, Faber predicts all galaxies will ultimately be sorted and explained by just two parameters: mass and radius. "There's a galaxy law that we're only now discovering that makes it simple."

But many galaxy modelers believe the recipes will always be complicated and uncertain. Galaxy formation may be like the weather, which keeps precise predictions forever out of reach because of its chaotic nature, Springel says. "I'm a little bit concerned that we'll understand the big picture but never understand the details," he says. In that case, the increasing realism of galaxy simulations may serve only to underscore a fundamental complexity in the universe.

The link you point to on satellite galaxies and the dark matter parameters we can extract from observation of Milky Way's satellites I would take as showing that we have less problems with Milky Way especially and dark matter in general. They confirm our understanding of both. And as a direct rejection of the somewhat "moon shot" continued search for scalar, axion like mass, dark matter you link to as somehow telling on dark matter in general. Those particles are natural in string theory but not seen since dark matter would be "fuzzy" and wave like, not cold and particle like https://scitechdaily.com/is-dark-matter-warm-cold-or-fuzzy-new-simulations-provide-intriguing-insights/ ].


A simulation of early galaxy formation under three dark matter scenarios. In a universe filled with cold dark matter, early galaxies would first form in bright halos (far left). If dark matter is instead warm, galaxies would form first in long, tail-like filaments (center). Fuzzy dark matter would produce similar filaments, though striated (far right), like the strings of a harp. Credit: Image courtesy of the researchers
The amount of dark matter spread out in the whole solar system averages an asteroid mass worth, much likely settled inside the Sun to boot. Why would you expect to see that gravitationally? https://www.forbes.com/sites/startswithabang/2018/03/24/ask-ethan-if-dark-matter-is-everywhere-why-havent-we-detected-it-in-our-solar-system/ ]

Because we know the mass of the Milky Way, the relative densities of normal and dark matter, and we have simulations that tell us how the dark matter density ought to behave, we can come up with some very good estimates. When you do these calculations, you find that about 10^13 kg of dark matter ought to be felt by Earth’s orbit, while around 10^17 kg would be felt by a planet like Neptune.

But these values are tiny compared to the other masses of consequence! The Sun has a mass of 2 \00d7 10^30 kg, while Earth is more like 6 \00d7 10^24 kg. Values like the one we came up with, in the 10^13 – 10^17 kg range, are the mass of a single modest asteroid. Someday, we may understand the Solar System well enough that such tiny differences will be detectable, but we’re a good factor of 100,000+ away from that right now.