General Introduction

This guide is designed to aid the new user in deriving scientific results from reduced x-ray data using the SAO PROS software system which runs under IRAF as package ``xray". We give the basic instructions for running the tasks, some scientific justifications and a few details - where relevant to the task at hand - on the IRAF/PROS system. This document also contains a list of useful IRAF documents.

Each chapter contains examples on how to achieve specific scientific goals. It does not cover all the available options and tasks. Comprehensive, on-line help files are available for all tasks, and users are referred to those for details.

IRAF runs on a variety of computers and under several operating systems. This guide will not cover all the possible ways to get started. If you are using the IRAF/PROS system at SAO, you will find the siteguide, by Belinda Wilkes, a useful guide to site-specific procedures. For other sites, see the analogous documents or your local IRAF experts.

Please note that the examples in this document have been tested `live' on SUN-Unix systems. Although we have tried to make these examples as `operating system independent' as possible, there may be residual details that do not apply to other systems.

NOTE: In most cases Examples shown in this guide use the REV0 filenames of the sample data in xdata$. RDF sample data is now distributed by PROS and can be used when running PUG examples. They are available in xdata$ with a slight filename change (``n00'' added to sequence number, i.e. rh110267n00.qp).

Throughout this document, statements typed by the computer are in typewriter font, and user inputs are in regular roman fonts. Italics will be used for IRAF terminology and file names. Your computer name (and system prompt) will be printed as ``cfa#''. When two single quotes are juxtaposed, they should be interpreted as a (normal) double quote.

There are many scientific objectives that can be accomplished with the IRAF PROS package. These include:

• Image Display
  • Within Sunview (Sun computers only) (using IRAF imtool)
  • Within Xwindows (using SAOimage)
• Spatial analysis
  • Extract counts within specified regions
  • Extract a count distribution (radial and azimuthal profiles)
  • Correct images for exposure and vignetting
  • Smooth images
  • Plot isointensity contours on smoothed arrays
  • Keep track of errors

• Spectral analysis
  • Extract counts in pulse height bins for a specified region
  • Fit model spectra to the extracted data
  • Plot data and best-fit spectra
  • Plot $\chi ^{2}$ contours showing 90% confidence region, etc.
  • Determine fluxes and luminosities based on the spectral fits

• Timing analysis
  • Extract counts in specified time bins
  • Perform periodic and aperiodic timing analysis

In all cases the user has to read in the data and, if necessary, generate IRAF compatible files.