pychell API reference

Computing RVs

pychell.rvs.rvcalc.cc_wrapper(forward_model, n_spec_tot, iter_num)

Cross correlation wrapper for a single spectrum.

Parameters:
  • forward_model (ForwardModel) – A single forward model object.
  • n_spec_tot (int) – The total number of spectra.
  • iter_num (int) – The iteration to use.
pychell.rvs.rvcalc.compute_bisector_span(cc_vels, ccf, n_bs=1000)

Computes the bisector span of a given cross-correlation (RMS brute force) function.

Parameters:
  • cc_vels (np.ndarray) – The velocities used for cross-correlation.
  • ccf (int) – The corresponding 1-dimensional RMS curve.
  • n_bs (int) – The number of depths to use in calculating the BIS, defaults to 1000
Returns:

The line bisectors of the ccf. bisector_span (float): The bisecor span of the line bisector (commonly referred to as the BIS).
Return type:

line_bisectors (np.ndarray)
pychell.rvs.rvcalc.cross_correlate_all(forward_models, iter_num)

Cross correlation wrapper for all spectra.

Parameters:
  • forward_models (ForwardModels) – The list of forward model objects.
  • iter_num (int) – The iteration to use.
pychell.rvs.rvcalc.cross_correlate_star(forward_model, iter_num)

Performs a cross-correlation via brute force RMS minimization and estimating the minumum with a quadratic.

Parameters:
  • forward_model (ForwardModel) – A single forward model object.
  • iter_num (int) – The iteration to use.
Returns:

The forward model object with cross-correlation results stored in place.
Return type:

forward_model (ForwardModel)
pychell.rvs.rvcalc.generate_rvs(forward_models, iter_num)

Genreates individual and nightly (co-added) RVs after forward modeling all spectra and stores them in the ForwardModels object. If do_xcorr is True, nightly cross-correlation RVs are also computed along with the line bisector and BIS.

Parameters:
  • forward_models (ForwardModels) – The list of forward model objects.
  • iter_num (int) – The iteration to generate RVs from.
pychell.rvs.rvcalc.get_nightly_jds(jds, sep=0.5)

Computes nightly (average) JDs (or BJDs) for a time-series observation over several nights.

Parameters:
  • jds (np.ndarray) – An array of sorted JDs (or BJDs).
  • sep (float) – The minimum separation in days between two different nights of data, defaults to 0.5.
pychell.rvs.rvcalc.plot_rvs(forward_models, iter_num)

Plots all RVs and cross-correlation analysis after forward modeling all spectra.

Parameters:
  • forward_models (ForwardModels) – The list of forward model objects.
  • iter_num (int) – The iteration to use.