skip to content
 
ROSAT Guest Observer Facility

XSELECT/PCARF warning

There is a bug in the xselect extractor which causes some incorrect keyword values to be written to the header of ROSAT PSPC spectra extracted via xselect. The CDELT1 and CDELT2 keywords are affected and these are used by the task PCARF. The incorrect values result in the following error message:

** US Rev0 data may have wrong value in PHA file. Standard value is DELTX=2. 595021E -4. ** GT_WMAP 1.2.0 WARNING: X pixel size of wmap is 1.3888890000000D- 04 degrees. Are you sure about this? **

This message falsely indicates the spectrum was from USrev0 data, this is because an older (fixed) problem also used to give result in a wrong keyword value-and this warning was written for that case. However, the warning is valid in that it does indicate a keyword problem. To work around this problem, please invoke PCARF thus:

pcarf deltx=2.595021E-4 delty=2.595021E-4

This over-rides the bad values in the header. The extractor bug has been fixed and the fixed code will be available in the next release of ftools.

If you need more detail, please contact us via the Feedback form


Curator: Michael Arida (SP Sys); arida@milkyway.gsfc.nasa.gov
HEASARC Guest Observer Facility
Please use the Feedback link if you have questions on ROSAT.

This file was last modified on Friday, 19-Jul-2002 11:56:44 EDT

NASA Astrophysics

  • FAQ/Comments/Feedback
  • Education Resources
  • Download Adobe Acrobat
  • A service of the Astrophysics Science Division (ASD) at NASA/ GSFC

    ROSAT Project Scientist: Dr. Robert Petre

    Responsible NASA Official: Phil Newman

    Privacy Policy and Important Notices.