The core science tools are:

• gtlikelihood, gtexpmap, and associated utilities – for defining a model of a region of the sky and fitting it by maximizing the likelihood function.

• gtrspgen, gtbin – for generating response matrices and counts spectra for analysis of GRBs in XSPEC, including jointly with GBM data.

• gtbary, gtpphase, gtpsearch, and associated utilitites - for pulsar timing, periodicity tests.

• gtobssim, gtorbsim – fast and flexible observation simulator using the instrument response files (IRFs), and an orbit/attitude simulator