Scivillage.com Casual Discussion Science Forum

https://www.eurekalert.org/news-releases/1055328

INTRO: When astronomers got their first glimpses of galaxies in the early universe from NASA’s James Webb Space Telescope, they were expecting to find galactic pipsqueaks, but instead they found what appeared to be a bevy of Olympic bodybuilders. Some galaxies appeared to have grown so massive, so quickly, that simulations could not account for them.

Some researchers suggested this meant that something might be wrong with the theory that explains what the universe is made of and how it has evolved since the big bang, known as the standard model of cosmology.

According to a new study in The Astrophysical Journal led by University of Texas at Austin graduate student Katherine Chworowsky, some of those early galaxies are in fact much less massive than they first appeared. Black holes in some of these galaxies make them appear much brighter and bigger than they really are.

“We are still seeing more galaxies than predicted, although none of them are so massive that they ‘break’ the universe,” Chworowsky said.

The evidence was provided by Webb’s Cosmic Evolution Early Release Science (CEERS) Survey, led by Steven Finkelstein, a professor of astronomy at UT and study co-author... (MORE - details)

Official verdict: JWST’s early galaxies didn’t break cosmology
https://bigthink.com/starts-with-a-bang/...cosmology/

EXCERPT: Today, the most massive black holes are huge, with tens of billions of solar masses inherent to them: about 0.1% of the stellar mass of those galaxies. But early on, black holes were still very massive, with tens of millions, hundreds of millions, or even a billion solar masses in just the first ~800 million years of cosmic history. Importantly, however, the galaxies that house them are much lower in mass than they are today, so that the black hole-to-stellar mass ratio of these galaxies isn’t 0.1%, but can be 1%, 10%, or even up to 100%. These are known as overmassive black holes, and when they’re active, they can shine very, very brightly.

All black holes, but especially overmassive black holes, can consume gas from their surroundings, and when they do, they heat the gas up. It can get so hot that the gas doesn’t just emit infrared (heat) light, but it can emit visible, ultraviolet, and even X-ray light. When we see a “little red dot” in the sky with JWST’s eyes, we’re seeing the sum total of all the light produced: light from the stars inside plus light from any active supermassive black hole activity occurring inside. Since they only appear as a single point, it’s very difficult to disentangle what light comes from what component of the galaxy. What’s remarkable is that — as has been done in a new study — when you account for this black hole-produced light in these “little red dots,” the remaining early galaxies are right in line with what the standard model of cosmology, or ΛCDM, predicts... (MORE - missing details)