Kepler: Photometric Transit Modeling & Analysis Suite

Source code for NASA's Kepler Mission photometric transit modeling, light curve detrending, transit discovery, and Markov Chain Monte Carlo (MCMC) parameter estimation.

Author: Jason F. Rowe (jasonfrowe@gmail.com)

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Prerequisites

• Fortran Compiler: GFortran (GCC 10+) or Intel Fortran (ifort/ifx) with OpenMP support.
• C Compiler: GCC or Clang (gcc).
• Graphics: X11 / XQuartz (for interactive PGPLOT plotting).
• Libraries:
  • CFITSIO: For reading MAST FITS light curve files.
  • PGPLOT: For interactive light curve, model, and posterior distribution plots.

1. Installing Dependencies on macOS (Homebrew)

Install CFITSIO and XQuartz via Homebrew:

brew install cfitsio
brew install --cask xquartz

Building PGPLOT from Source on macOS

PGPLOT is compiled locally (e.g. into ~/Software/pgplot/build):

mkdir -p ~/Software/pgplot/build
cd ~/Software/pgplot/build
cp ../drivers.list .

1. Enable the desired drivers in drivers.list (e.g., /NULL, /PNG, /TPNG, /PS, /VPS, /CPS, /VCPS, /XWINDOW, /XSERVE).
2. Generate the Makefile with makemake using the Darwin GFortran configuration:

   ~/Software/pgplot/makemake ~/Software/pgplot darwin gfortran_gcc

3. Build the library:

   make libpgplot.a

PGPLOT Environment Setup

Add the following to your ~/.zshrc or ~/.bashrc:

export PGPLOT_DIR=$HOME/Software/pgplot/build/
export PGPLOT_DEV=/xserve   # Preferred interactive output device

2. Installing Dependencies on Linux

Install required packages via your distribution's package manager:

# Debian / Ubuntu
sudo apt install gfortran libcfitsio-dev pgplot5 libpng-dev

# Fedora / RHEL / CentOS
sudo dnf install gcc-gfortran cfitsio-devel pgplot-devel libpng-devel

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Quick Installation

Option A: Standard Build (Autoconf) — Recommended

./autogen.sh
./configure
make -j4

Option B: Direct Build (Make)

make -j4

Notes:

• ./autogen.sh generates ./configure from configure.ac using autoreconf.
• Compiled binaries are automatically placed in the centralized ./bin/ directory.

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Overview of Modules & Executables

1. TRANSITFIT5

Photometric transit modeling, radial velocities, transit timing variations (TTVs), and Differential Evolution MCMC (deMCMC) posteriors.

Executable	Description
transitfit51	Modern Fortran 90 Levenberg-Marquardt optimizer for multi-planet transit models.
transitfit5	Levenberg-Marquardt photometric transit model fitter.
transitmcmc5	Parallelized Differential Evolution MCMC (deMCMC) posterior sampler.
transitcut5	Trims light curve photometry beyond $\pm$ transit durations.
sigclip	Outlier rejection routine via iterative $\sigma$-clipping.
transitsn5	Estimates transit signal-to-noise ratios (S/N) based on transit models.
transittiming5	Fits individual center-of-transit times for TTV analysis.
transitdepth5	Computes transit depths from model parameters.
transitplot5	Interactive PGPLOT visualization of phase-folded light curves and transit models.

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2. DATATEST

MAST FITS light curve reading, data processing, and polynomial detrending routines.

Executable	Description
detrend51	Parallelized out-of-transit running polynomial baseline detrending filter.
detrend5	Detrends light curves while preserving transit signals via input transit models.
kfitsread	Reads MAST Kepler FITS light curve files (CFITSIO).
sigclip	Outlier clipping utility.

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3. TRANSITFIND

Exoplanet transit discovery and search algorithms.

Executable	Description
transitfind5	Optimized Box-fitting Least Squares (BLS) transit search algorithm.
transitfind2	Standard BLS transit search.
pdmsearch	Phase Dispersion Minimization (PDM) periodic signal search.

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Citation & References

If you make use of this codebase in your research, please cite:

• Rowe et al. (2014), Validation of Kepler's Multiple Planet Candidates. III. Light Curve Analysis & Performance ...., ApJ, 784, 45. [DOI:10.1088/0004-637X/784/1/45]
• Rowe et al. (2015), Planetary Candidates Observed by Kepler. V. Planet Sample from Q1–Q16 (47 Months), ApJS, 217, 16. [DOI:10.1088/0067-0049/217/1/16]
• Jason Rowe (2016), Kepler: Kepler Transit Model Codebase Release [Data set]. Zenodo. [DOI:10.5281/zenodo.60297]