Original Sherpa and CIAO code is
Copyright (c) 2004-2015 Smithsonian Astrophysical Observatory

Sherpa is released under the terms of the GNU General Public Licence (GPL)
Version 3 (or at your option any later version).

Sherpa includes, redistributes, and/or links against third party software in
its original form or modified according to its license terms.
Copyright for third party software belongs to the original authors.

The original copyright notice and license terms were included in the
appropriate source code files according to the terms of the licenses
under which they were originally released.

We include below the list of codes that Sherpa includes, redistributes,
and/or links against. If you think the information below contains any errors
please contact us at cxchelp [at] head.cfa.harvard.edu

To the best of the Sherpa authors knowledge, all the licenses for the software
listed below are compatible with the GPLv3 license, and in compliance with
their licenses Sherpa is released under the terms of the GPLv3 license.

GNU Scientific Library, various authors, released under the terms of the
GNU General Public Licence v2+

Pileup, rebin_histogram, by John E. Davis, for the
Massachusetts Institute of Technology, release under the terms of the
GNU General Public License v2+

adapt_integrate, by Steven G. Johnson, based on GNU GSL by Brian Gough
and HIntLib by Rudolf Schuerer, all distributed under the terms of the
GNU General Publice License v2+

fftn, various authors, is released under the terms of the GPL
license.

pyfits, various authors, released under the terms of the BSD license:
see http://www.stsci.edu/institute/software_hardware/pyfits

numpy, various authors, released under the terms of the 3-clause
BSD license, see http://www.numpy.org/

matplotlib, various authors, release under the terms of the
PSF license, see http://matplotlib.org/

wcssubs, by Jessica Mink for the Smithsonian Astrophysical
Observatory. The code may be derived from other authors, full
information is available in the extern/wcssubs/ directory
of this archive. wcssubs is released under the terms of the
LGPLv2.1+ license.

fftw3, various authors, released under the terms of the GPLv2+
license.

Xspec 12 was developed by Keith Arnaud, Ben Dorman, and Craig Gordon,
HEASARC Software Development, Astrophysics Science Divsion,
Code 660.1, NASA/GSFC, Greenbelt MD 20771

libgfortran, various authors, is released under the terms of the
GPLv3 license, with the GCC Runtime Library Exception.

minim.f and syminv, various authors, are released in the public domain.

cephes library, various authors, is released under the terms of the
GPLv3+ license.

minpack was developed by the University of Chicago, as Operator of
Argonne National Laboratory, under the terms described at:
http://netlib.org/minpack/disclaimer