In the Dark

Some time ago I blogged about how one can use gravitational waves to estimate the Hubble Constant, H₀. Well, about a month ago the LIGO people produced a user-friendly update on progress in that regard which you can find here.

The full paper (i.e. author list plus a small amount of text) can be found here. Here are two plots from that work.

The first shows the constraints from the six loudest gravitational wave events selected for the latest work, together with the two competing measurements from Planck and SH0ES:

As you can see the individual measurements do not constrain very much. The second plot shows the effect of combining all relevant data, including  a binary neutron star merger with an electromagnetic counterparts. The results are much stronger when the latter is included

Obviously this measurement isn’t yet able to resolve the alleged tension between “high” and “low” values described on this blog passim, but it’s early days. If LIGO reaches its planned sensitivity the next observing run should provide many more events. A few hundred should get the width of the posterior distribution shown in the second figure down to a few percent, which would be very interesting indeed!

This entry was posted on March 22, 2021 at 12:49 pm and is filed under The Universe and Stuff with tags Advanced LIGO, Binary Neutron Stars, gravitational waves, GW170817, Hubble constant. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.