5

So far my understanding of BAOs is that they are a relic of the old universe formed by the freezing of acoustic density waves in baryonic matter as the universe entered the recombination epoch. These oscillations can be used as a "standard ruler" for length scale, providing means to calculate Hubbles Constant.

I don't understand how this then links to evidence for dark matter.

Any help on this would be very much appreciated. Thanks :)

anna v
  • 236,935
user333276
  • 61
  • 1

1 Answers1

3

I don't think there is a direct connection to dark matter. Take this figure from the first observation paper:

BAO

The top three fits (green, red, blue) are models with baryonic matter and dark matter, the bottom fit (magenta) is dark matter only. So, no baryons, no BAO; or if you measure BAO, you can infer the baryonic density.

The connection to dark matter comes only indirectly, in that a consistent picture requires both dark matter and baryonic matter to fit all available data (including the CMB, etc).

rfl
  • 6,545