Version 1.2.7  

Epoch Folding

 

Epoch Folding Functions

The epoch folding function implements the L-statistic, as described by Davies (1990, MNRAS, vol. 244, pp. 93-95).

  1. sitar_epfold_rate( t, rate [, pstart, pstop] [; nphs=#, nsrch=#, loggrid, prds=array] )
    Epoch fold a rate lightcurve for a range of trial periods, and return the statistical value of the period.
    Run as: isis> fold = sitar_epfold_rate(t,rate,pstart,pstop;nphs=#,nsrch=#,prds=array);
    Variables in [] are optional (qualifiers after the semi-colon).
    Omitted variables take on default values.

    Inputs:
    • t : Times at which rates are measured
    • rate : Lightcurve rate
    • pstart : Starting value of periods to search
    • pstop : Stopping value of periods to search
    (Semi-)Optional Inputs (required if qualifier prds=array not set):
    • pstart : Starting value of periods to search
    • pstop : Stopping value of periods to search
    Optional Qualifier Inputs:
    • nphs : Number of phase bins in folded lightcurve Default = 20, minimum = 2 (unless prds is set)
    • nsrch : abs(nsrch) = number of periods to search.
    • loggrid : If input, the period search grid is logarithmic.
    • prds : Alternative array of periods to search
    Outputs:
    • fold.prds : Array of trial periods
    • fold.lstat : Array of L-statistic for trial period
    • fold.lsig : Array of log10 of *single trial* significance levels. Note: This requires use of the GNU Scientific Library package from the S-Lang Modules Packages. Otherwise, the array defaults to a value of 1.
    • fold.nphs : Array of number of phases (<= nphs) at a given period that had data.

This page was last updated May 2, 2017 by Michael Nowak. To comment on it or the material presented here, send email to mnowak@space.mit.edu.
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