ISIS is designed to facilitate the interpretation and analysis of high resolution X-ray spectra.

ISIS (Interactive Spectral Interpretation System) is designed to facilitate the interpretation and analysis of high resolution X-ray spectra. It is being developed as a programmable, interactive tool for studying the physics of X-ray spectrum formation, supporting measurement and identification of spectral features, and interaction with a database of atomic structure parameters and plasma emission models.

Here are some key features of "ISIS":

· Efficiently generate multi-component spectral models using the APEC/APED spectroscopy database for collisionally ionized plasmas, including user-defined line profiles.
· Automatically generate custom, multi-component APEC/APED fit-functions for specialized applications.
· Examine ionization balance tables plus data on individual emission lines and continua.
· (optional) Use new ISIS functionality with familiar XSPEC models. All XSPEC additive, multiplicative and convolution models are available, including table models and local models.
· Analyze data formatted as ASCII files or FITS Type I or Type II PHA files.
· Fit scatter data.
· Read arbitrary FITS files and columnar ASCII tables.
· Rebin your data interactively, with direct control over how uncertainties are propagated.
· Factor an RSP matrix into an ARF and a normalized RMF.
· Fit spectral models to your data either directly, or by folding models through the instrument response.
· Generate fake data for Monte-Carlo analysis of model uncertainties and for proposal planning.
· Analyze piled-up CCD spectra using the model developed by John Davis (MIT).
· Do multi-order spectral analysis (e.g. using the Chandra/LETGS) by assigning multiple instrument responses to a single dataset.
· Fit multiple data sets simultaneously, including an optional instrumental background component.
· Easily combine multiple datasets, fitting a model to the summed data.
· Define fit-parameters as arbitrary functions of other fit-parameters (including inequality constraints).
· Impose arbitrary fit-constraints by introducing user-defined penalty functions.
· Compute single-parameter confidence limits
· Generate confidence contour maps; save and re-read as FITS images; plot and overplot contours.
· Fit user-defined models coded in S-Lang, C or Fortran
· Apply user-defined fit-statistics coded in S-Lang, C or Fortran
· Apply user-defined fit-methods coded in C or Fortran
· Apply user-defined RMFs defined in software (rather than as a FITS file)
· Dynamically load C, C , and FORTRAN code from external modules
· With the PVM module, distribute computationally expensive tasks across a network of workstations.

What's New in This Release:

· Loading of xspec12 local models was enabled.
· Support for the S-Lang debugger and profiler was added.
· The create_aped_line_modifier now supports modifiers that take additional user-defined arguments.
· xspec table models now load parameter defaults from the table file.
· Support for the analysis of INTEGRAL data was added.
· The performance of APED spectral models that use a line modifier was improved.
· The code was cleaned up and bugs were fixed.