HETGS Line Profiles  

Caveats on Using the LSF Library


Caveats on using the LSF library

The users must be aware of five caveats on using the LSF library:
  • The library works the best for the point source placed on the nominal aim point for science intrument,

  • in CIAO/tg_extract tool, set the keywords:
    abs|min\_tg\_d| = max\_tg\_d,
    so that the extraction region is centered around the tg_d value = 0.0 deg (see Figure 6 below):

    Caveat on the extraction region
    Figure 6: Caveat on the extraction region. Because of the way that EEFRACS is numerically derived, the extraction region must be centered at tg_d = 0.0 deg.

  • extraction widths should be greater than 2 ACIS CCD pixels (or 0.00014deg),

  • pixel randomization in tg_resolve_events must be set to 0.5pix (defined as default),

  • the LSF library support +1 order only, though the library seems to work O.K. with -1 order as well(*) as other higher orders.
(*) Not explicitly true for HEG as one of the HRMA mirror shell is misaligned appreciably.

The next section demonstrates the validity of the LSF library.

Previous: LSFPARM library Next: Validation

This page was last updated Dec 4, 2002 by Bish K. Ishibashi. To comment on it or the material presented here, send email to bish (at) space.mit.edu.
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