compute_modshift_metrics

exovetter.modshift.compute_modshift_metrics(time, flux, model, period_days, epoch_days, duration_hrs, show_plot=True)[source]

Compute Jeff Coughlin’s Modshift metrics.

This algorithm is adapted from the Modshift code used in the Kepler Robovetter and documented on https://exoplanetarchive.ipac.caltech.edu/docs/KSCI-19105-002.pdf

(see page 30, and appropriate context)

Jeff uses modshift to refer to both the transit significance tests, as well as a suite of other, related, tests. This code only measures the metrics for the transit significance measurements.

The algorithm is as follows:

  • Fold and bin the data

  • Convolve binned data with model

  • Identify the three strongest dips, and the strongest positive excursion

  • Remove some of these events, and measure scatter of the rest of the data

  • Scale the convolved data by the per-point scatter so that each point represents the statistical significance of a transit signal at that phase.

  • Record the statistical significance of the 4 events.

Parameters:
time

(1d numpy array) times of observations in units of days

flux

(1d numpy array) flux values at each time. Flux should be in fractional amplitude (with typical out-of-transit values close to zero)

model

(1d numpy array) Model transit flux based on the properties of the TCE len(model) == len(time)

period_days, epoch_days, duration_hrsfloat

Properties of the transit

show_plotbool

Display plot. This needs matplotlib to be installed.

Returns:
resultsdict
Raises:
ValueError

Invalid inputs.