act_dr6

Full Multi-Frequency primary CMB from ACT DR6 data including systematics and foregrounds.

File

likelihood/act-dr6/act_dr6_interface.py

Attribution

Xavier Garrido, Serena Giardiello, ACT Collaboration (Library)

Ian Harrison, CosmoSIS Team (Interface)

URL

https://github.com/ACTCollaboration/act_dr6_mflike

Citations

https://arxiv.org/abs/2503.14452

Important note: please see https://github.com/ACTCollaboration/ACT-DR6-parameters/blob/main/theories/camb.yaml for the default CAMB settings required for this likelihood to reproduce the published result. This also requires the use of the CosmoRec recombination module which is not supplied by default in CAMB. This repo also specifies default priors for the likelihood, including the tau prior which should be used if no large scale CMB polarisation data (e.g. from Planck SRoll2) is included.

This is the full multi-frequency MFLike primary CMB likelihood from the ACT DR6 data release. This includes a full set of foreground and instrumental systematics modelling parameters. For a lighter version of the likelihood including only two nuisance parameters, which gives the same results in Lambda-CDM cosmologies, it is suggested to use the `lite’ version also provided. What is supplied here is only the CosmoSIS interface to the official Cobaya likelihood. This should be obtainable through installing the Cobaya likelihood from the provided github repository. The required data can be downloaded with the provided shell script.

Assumptions

  • act_dr6_mflike python module

  • ACT DR6 multi multi-frequency data

Setup Parameters

None

Input values

Section

Name

Type

Default

Description

cmb_cl

tt

real 1d

Lensed CMB temperature power spectrum in ell(ell+1)/2pi units

te

real 1d

Lensed CMB temperature-E-mode polarization cross power spectrum in ell(ell+1)/2pi units

ee

real 1d

Lensed CMB E-mode polaration power spectrum in ell(ell+1)/2pi units

act_params

A_act

real

1.0

Overall ACT calibration parameter used to model residual systematics.

P_act

real

1.0

Overall ACT polarisation efficiency parameter used to model residual systematics.

Output values

Output values

Section

Name

Type

Description

likelihoods

act_dr6_lite_like

real

ACT DR6 primary CMB-only likelihood for given selection