The utils module implements a set of convenience functions that are used througout the library.

  • find_first_of: This function will find the index of the first element in an array that exceeds a given threshold value. The function is used a number of times to dissect light curve or event data into discrete blocks.
  • truncate: This function will

GTI tools

The GTI Tools subpackages offers a set of functions that manage good time intervals. Available tools are

  • durations – computes the GTI exposures
  • trunctate – truncate a list of GTIs to a lower and/or upper boundary in time.
  • good_to_bad – convert between good time and bad time
  • bad_to_good – convert between good time and bad time
  • merge – merge two GTI lists using and/or logic


The Ftools subpackage wraps around the heasoft FTOOLS and allows the user to call a number of operations on a fits file. These ftool operations are performed in a subproccess outside the python environment, but can be useful in preparing or cleaning the data for analysis.