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To find and download HEASARC data in the cloud, you can use astroquery.heasarc or download our new tool, hark.

The HEASARC and NuSTAR teams are greatly saddened by the sudden passing of Katja Pottschmidt. Most recently Katja was the lead scientist for the NuSTAR Guest Observer Facility (GOF), a role she had supported for many years. During her science career she worked on many other high energy astrophysics missions and played an integral role in advancing our knowledge of the universe. She was a wonderful colleague and friend and will be keenly missed by all who knew her.

Special Characters

XPI recognizes the following special characters:


! - indicates the rest of the line is a comment
@ - starts reading commands from a command file
$ - spawn to the system
" - protects other special characters
= - seperate parameter-value pairs


As a result, you should observe the following rules when entering expressions on the command line.


  • An argument with imbedded spaces must be delimited by double quotes.
  • An argument containing an @ or a ! must be surrounded by double quotes.
  • = signs are trapped by XPI, so use .eq. in selection expressions, or surround your expressions with double quotes. In fact, to be safe it is always best to do this anyway.