Skip to main content

The NASA/GSFC network is currently experiencing intermittent issues that affect our services. We are working on it and apologize for the inconvenience.
The offline tool hark (also on github) can be used to find and download data from the cloud.

Xspec Home Page

Commands

XSPEC commands can be divided into 6 categories: Control, Data, Model, Fitting, Plotting and Setting, as follows:

  • Control commands include items such as controlling logging, obtaining help, executing scripts, and other miscellaneous items to do with the program control rather than manipulating data or theoretical models.
  • Data commands load spectral data and calibration data such as backgrounds and responses, and specify channel ranges to be fit.
  • Model commands define and manipulate theoretical models and their parameters, and compute additional information such as fluxes or line identifications.
  • Fit commands initiate the fitting routines, control the parameter set, perform statistical tests and compute confidence levels.
  • Plot commands generate about 50 different kinds of 2-dimensional plots
  • Setting commands change a variety of XSPEC internals which control details of models, statistics, and fitting methods.
These command types are summarized below. For full details see Chapter 5.