I want to learn more about 'little red dots'. In March last year, astronomers were shocked to find these objects in the very early universe, just 600 million years after the Big Bang. That seemed too soon for galaxies to form.

Now Avi Loeb has a theory to explain them.

Aliens!

Just kidding. It's amazing how he's managed to discredit himself so thoroughly. But he's had some good ideas and may continue to do so. This new work was done with Fabio Pacucci at Harvard.

Their theory is that little red dots formed from the collapse of dark matter clouds that happened to have low angular momentum. Most of the dark matter clouds spin around too fast to collapse quickly. They collapse more slowly - and pull visible matter along with them, creating the galaxies we see.

(That at least is the standard theory. We need dark matter to explain galaxy formation and many other things.)

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https://media.mathstodon.xyz/media_attachments/files/115/179/389/073/966/794/original/e92ff9f1d3afcbd5.webp

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Discussion

Fabio Pacucci and Abraham Loeb claim that the most common little red dots, found at redshift z = 5, are explained as galaxies formed in the lowest ∼1% of the halo spin distribution. This naturally reproduces both their observed abundance (∼1% of standard galaxies) and their compact sizes (effective radius < 300 parsecs).

They aren't making any claims about the precise structure of little red dots. They may be black holes, they may not, etc.

They claim this theory fits some of the statistics of little red dots.

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https://iopscience.iop.org/article/10.3847/2041-8213/ade871