CMB from BICEP/Keck XIII October 2021


Likelihood of BICEP/Keck, October 2021 (2018 data)


BICEP/Keck Collaboration and Antony Lewis


If you use this likelihood, please cite it as:
Keck Array and BICEP2 Collaborations, BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season (arXiv:2110.00483v1)


To use this likelihood, bicep_keck_2018, you simply need to mention it in the likelihood block, or add them using the input generator.

The corresponding nuisance parameters will be added automatically, so you don’t have to care about listing them in the params block.

The nuisance parameters and their default priors are reproduced below, in the defaults yaml file.

You shouldn’t need to modify any of the options of this simple likelihood, but if you really need to, just copy the likelihood block into your input yaml file and modify whatever options you want (you can delete the rest).

# BICEP/Keck October 2021 Data Products
# BICEP/Keck XIII: Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
# File: BK18lf.ini
# Date: 2021-10-03
# BICEP/Keck likelihood, including external data from Planck and WMAP.
# Default settings for data selection and foreground nuisance parameters from 
# the baseline analysis described in BICEP/Keck XIII.
#   * Includes BICEP2+KECK+BICEP3 95, 150, and 220 GHz maps
#   * Additional maps are: Planck 30, 44, 143, 217, and 353 GHz; 
#                          WMAP 23 GHz (K-band) and 33 GHz (Ka-band), 
#                          apodized to BICEP3 map size
#   * Maps apodized to BICEP3 map size are denoted with letter 'e', 
#     otherwise they are apodized to BICEP2/Keck map size instead.
#   * By default uses B-modes only.
#   * Uses all nine ell bins.
#   * Gaussian priors on beta_dust and beta_sync.
#   * Dust blackbody temperature fixed to 19.6 K because this parameter
#     is degenerate with A_dust for our frequency range.
#   * Dust and sync decorrelation turned off by default.
#   * EE/BB ratio for dust and sync fixed to 2 (not relevant for analysis
#     with B modes only)
#   * Band center errors turned off by default.

# Path to the BK18_cosmomc folder under the official data distribution
path: null
dataset_file: BK18_cosmomc/data/BK18lf_dust/BK18lf_dust.dataset
  maps_use: [BK18_K95_B, BK18_150_B, BK18_220_B, BK18_B95e_B, W023e_B, P030e_B, W033e_B, P044e_B, P143e_B, P217e_B, P353e_B]
  use_min: 1
  use_max: 9
map_separator: x
# Actually computed l_max (takes into account the lensing window function)
l_max: 2700
# Aliases for automatic covariance matrix
aliases: [BK15]
# Speed in evaluations/second
speed: 90
# Functional form of ell scaling for foreground decorrelation model.
lform_dust_decorr: lin
lform_sync_decorr: lin

  # dust power at ell=80, nu=353 GHz [uK^2]
      min: 0
      max: 15
      dist: norm
      loc: 3
      scale: 0.1
    proposal: 0.1
    latex: A_{B,\mathrm{dust}}
  # sync power at ell=80, nu=23 GHz [uK^2]
      min: 0.0
      max: 50.0
      dist: norm
      loc: 1.0
      scale: 1.0
    proposal: 1.0
    latex: A_{B,\mathrm{sync}}
  # dust spatial power spectrum power law index
      min: -1.0
      max: 0.0
      dist: norm
      loc: -0.42
      scale: 0.01
    proposal: 0.01
    latex: \alpha_{B,\mathrm{dust}}
  # sync spatial power spectrum power law index
      min: -1.0
      max: 0.0
      dist: norm
      loc: -0.6
      scale: 0.01
    proposal: 0.01
    latex: \alpha_{B,\mathrm{sync}}
  # dust SED power law index
  # relax beta_d prior - use flat prior on range [0.80, 2.40]
      min: 0.80
      max: 2.40
      dist: norm
      loc: 1.59
      scale: 0.02
    proposal: 0.02
    latex: \beta_{B,\mathrm{dust}}
  # sync SED power law index
      dist: norm
      loc: -3.1
      scale: 0.3
      dist: norm
      loc: -3.1
      scale: 0.02
    proposal: 0.02
    latex: \beta_{B,\mathrm{sync}}
  # correlation between dust and sync
  # NOTE: For BK15 analysis, we are allowing this parameter to range
  #       from -1 to 1 (allowed range was 0 to 1 for BK14).
      min: -1.0
      max: 1.0
      dist: norm
      loc: 0.2
      scale: 0.01
    proposal: 0.01
    latex: \epsilon_{\mathrm{dust,sync}}
  # EE/BB ratios -- fixed / only used if E-modes are turned on
  EEtoBB_dust: 2
  #   latex: 2EE_{\mathrm{dust}}/BB_{\mathrm{dust}}
  EEtoBB_sync: 2
  #   latex: 2EE_{\mathrm{sync}}/BB_{\mathrm{sync}}
  # dust blackbody temperature [K] -- fixed / very insensitive to this
  BBTdust: 19.6
  #   latex: T_{\mathrm{dust}}
  # dust correlation ratio between 217 and 353 GHz, ell=80
  delta_dust: 1.0
  # sync correlation ratio between 23 and 33 GHz, ell=80
  delta_sync: 1.0
  # Band center errors, fixed to zero
  gamma_corr: 0.0
  gamma_95: 0.0
  gamma_150: 0.0
  gamma_220: 0.0


This likelihood can be installed automatically as explained in Installing cosmological codes and data. If are following the instructions there (you should!), you don’t need to read the rest of this section.

Manual installation of the BICEP/Keck likelihood

Assuming you are installing all your likelihoods under /path/to/likelihoods, simply do

$ cd /path/to/likelihoods
$ mkdir bicep_keck_2018
$ cd bicep_keck_2018
$ wget
$ tar xvf BK18_cosmomc.tgz
$ rm BK18_cosmomc.tgz

After this, mention the path to this likelihood when you include it in an input file as

    path: /path/to/likelihoods/bicep_keck_2018