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DR4 Baseline CMB-only Likelihood described in Aiola et al. 2020

Product Name
CMB-only Likelihood Software
Mission
ACT

Description

This is the software used by the ACT collaboration to compute the likelihood of cosmological models, using the small-scale CMB power spectrum from 350 < l < 4000 measured with the ACTPol instrument, derived from seasons 2013-2016 of temperature and polarization data. These spectra have already been marginalized over SZ and foreground emission, and calibration and beam uncertainties. An overall polarization efficiency is the only nuisance parameter required to be sampled. It is based on the WMAP and ACT team's likelihood software.

To build, modify the data path in ACTPol_dr4_like.f90 and the Makefile to reflect your system's environment. Then

> make # Compiles the likelihood software and builds a test program.
> ./test # Runs the test program.

Please reference Choi et al. 2020 and Aiola et al. 2020 if you use this code.

Modifications to include and run the ACT DR4 likelihood in Cosmomc.

1. Modify the CMB.f90 file mirroring the one attached to include all ACT DR4 modifications required -- search for ACTPol or Erminia
2. Modify the Makefile to call your favourite compiler and add the 3 blocks below (follow the same order as for e.g., WMAP)

#set ACTPOL
ACTPol ?= /users/erminia/actpol/actpollite_dr4 #change to your likelihood path

#ACTPol
ifneq ($(ACTPol),)
FFLAGS += -DACTPol
LINKFLAGS += -L$(ACTPol) -lactpol
INCLUDE += $(IFLAG)$(ACTPol)
endif

# ACTPol
$(ACTPol)/libactpol.a:
        cd $(ACTPol); make libactpol.a;


3. In the batch2 folder create an ACTPol.ini file including the following

cmb_dataset[ACTPol] = ACTPol
bmin = 1
lmax_computed_cl = 6000
param[yp] = 1.0 0.9 1.1 0.05 0.01
use_fast_slow = F
sampling_method = 1

NOTE: bmin must be 1 for ACT alone or combination with WMAP or 24 for combination with Planck.

4. In the data folder create ACTPol.paramnames with the following line

yp   y_{P}

5. After this just call the batch2/ACTPol.ini in a basexx.ini file ready to run cosmology.

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Product Name
Python CMB-only Likelihood Software
Mission
ACT

Description

Downloadable python package: https://github.com/ACTCollaboration/pyactlike/workflows/Python%20package/badge.svg

This is the **Data Release 4 (DR4)** CMB power spectrum likelihood measured by the Atacama Cosmology Telescope (ACT), from the 2013-2016 survey covering >15,000 sq. deg. This spectrum has already been marginalized over SZ and foreground emission. The polarization efficiency is the only nuisance parameter required to be sampled. It is based on the WMAP and ACT team's likelihood software.

**Cite:** Aiola et al. 2020, Choi et al. 2020. This package is based off of the Fortran implementation written by Erminia Calabrese and Jo Dunkley. Thanks to Tim Morton for helping interface with Cobaya.

## Installation
To install, clone this repository and install it using pip.
```bash
git clone https://github.com/ACTCollaboration/pyactlike
cd pyactlike
pip install . --user
```

## Usage

This package can be called standalone or with [Cobaya][1]. For experimental MontePython support,
see the `montepython3/` directory in this repository. If you are using a Cobaya version < 2.1.0 (the current stable branch), please see the example Jupyter notebook in
`notebooks/Example for Cobaya (stable).ipynb`.

If you are on Cobaya 2.1.0
(currently the devel branch), using the likelihood is as easy as including it in your YAML
or configuration dict. There's one nuisance parameter, the polarization efficiency `yp2`.

[1]: https://github.com/CobayaSampler/cobaya
[2]: https://github.com/brinckmann/montepython_public

```
likelihood:
    pyactlike.ACTPol_lite_DR4:

params:
    yp2:
        prior:
            min: 0.5
            max: 1.5
```

We provide additional likelihood configurations for common uses,
* `pyactlike.ACTPol_lite_DR4_for_combining_with_Planck` for TT,TE,EE excluding the large scale ACT temperature
* `pyactlike.ACTPol_lite_DR4_onlyTT` for restricting only to TT
* `pyactlike.ACTPol_lite_DR4_onlyTE` for restricting only to TE
* `pyactlike.ACTPol_lite_DR4_onlyEE` for restricting only to EE


## Tests
Run `pytest` in the repository base directory run the tests.

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Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Alan P. Smale
LAMBDA Director: Dr. Eric R. Switzer
NASA Official: Dr. Eric R. Switzer
Web Curator: Mr. Michael R. Greason