About Iris

---

Iris is a downloadable Graphical User Interface (GUI) application which allows the astronomer to build and analyze wide-band Spectral Energy Distributions (SEDs). SED data may be loaded into Iris from a file on the user's local disk, from a remote URL, or imported directly from the NASA Extragalactic Database (NED) for analysis.

The components of Iris have been contributed by members of the Virtual Astronomical Observatory (VAO). Specview, contributed by STScI, provides a GUI for reading, editing, and displaying SEDs, as well as defining model expressions and setting initial model parameter values for spectral fitting. Sherpa, contributed by the Chandra project at the Smithsonian Astrophysical Observatory (SAO), provides a library of models, fit statistics, and optimization methods for analyzing SEDs; the underlying i/o library (SEDlib), also contributed by SAO, is written to the IVOA Spectrum Data Model 1.03 standard. NED is a service provided by IPAC at Caltech for easy location of the data available for a given extragalactic astronomical source, including SEDs. The SED Builder which is bundled with Iris, and contributed by SAO, is a tool for converting non-standard SED data files into a format supported by Iris, so that the file output by the tool may be loaded into Iris for analysis.

Communication between Specview and Sherpa is managed by a Simple Application Messaging Protocol (SAMP) connection. Specview packages SED data, model definitions and starting parameter values, and sends them to Sherpa whenever a fit to a SED is done. The goal is to seamlessly combine the power of Specview's GUI and data manipulation functions with Sherpa's robust modeling and fitting functions, as well as provide easy access to NED's extensive database of extragalactic SEDs. We have named this combined software package "Iris".

Bugs and caveats associated with the v1.2 release of the Iris software are documented on the Iris Bugs & Caveats page.

The VAO is being jointly funded by NSF and NASA, and is being managed by the VAO, LLC, a collaborative effort of the Association of Universities for Research in Astronomy (AURA), and the Associated Universities, Inc. (AUI).