CosmoCoffee

Hi there,

I am currently working on a small project in which I have obtained a constraint on the volume-averaged angular diameter distance [math]D_V = \left[ (1+z)^2 D_A^2 \frac{cz}{H(z)} \right] ^{1/3} (with the value of 1496 +20 -23) at an effective redshift [math]z_{eff} = 0.383 using the BOSS dataset.

Now I want to use Cobaya to combine this constraint on [math]D_V with the Planck data to obtain constraints on other cosmological parameters, most importantly the dark energy.

However, I have been having trouble figuring out a way to use this [math]D_V parameter in Cobaya. I have so far installed all the cosmological codes and data and used the cosmo-generator to get a yaml file for Planck input with CLASS. Do I now add [math]D_V to the list of all the parameters in the file and specify its priors? Or is it supposed to be a derived parameter? How do I then instruct Cobaya to use [math]D_V in working out the other parameters?

This is my first time using Cobaya so any help and tips would be greatly appreciated. Thank you.

Regards,
David

If you mean DV/r_s, then you just need to add your likelihood nothing else -e.g. adapt the provided sdss_dr7_mgs or sixdf_2001_bao (though you can also add DV as an output derived parameter if you want to)