Simple Spectral Access use cases

[Tom McGlynn]

> Simple Spectral Access Use Cases
> 
> Data Providers (e.g., data centers, archives)
> 
>     - Data provider name
            HEASARC

> 
>     - Spectral data collections from this source
            Variety of spectral data sources from X-ray and gamma-ray
            missions, including both relatively high and low resolution
	   spectral data.

> 
>     - Characteristics of data (number of spectra, size, irregularly sampled,
>       nonsampled (as in HE/UV) multiple flux arrays, variance arrays, etc.)
            Typically thousands of sources per mission.
            Many distinct spectral types, e.g.,
                Event lists (Einstein, ROSAT, ASCA, XMM) (individual photon events
                with energy information.  These can be the basis of spatial/spectral
	       data sets.)
                PHA files (Einstein, ROSAT, EXOSAT, XMM?) (these are most
                similar to conventional 1-d spectra)
                Time resolved spectral information (XTE, BATSE, Swift, HETE) (There
                are very complex formats here to deal with bright brief transients
                while XTE has a variety of modes to select between temporal and
                spectral resolution).
            Complex formats for calibration information
            Coded aperture mask data (INTEGRAL)

> 
>     - Current data storage format

                All data are stored in FITS formats

> 
>     - Is the data available online?

                Yes

> 
>     - Other comments

		Even at this leve of detail it may be inappropriate
		to discuss the HEASARC monolithically.  The characteristics
  		of individual missions/instruments varies enormously.