  RadVel is an open source Python package for modeling Keplerian orbits in
radial velocity (RV) time series. RadVel provides a convenient framework to fit
RVs using maximum a posteriori optimization and to compute robust confidence
intervals by sampling the posterior probability density via Markov Chain Monte
Carlo (MCMC). RadVel allows users to float or fix parameters, impose priors,
and perform Bayesian model comparison. We have implemented realtime MCMC
convergence tests to ensure adequate sampling of the posterior. RadVel can
output a number of publication-quality plots and tables. Users may interface
with RadVel through a convenient command-line interface or directly from
Python. The code is object-oriented and thus naturally extensible. We encourage
contributions from the community. Documentation is available at
http://radvel.readthedocs.io.
