|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:
(*) Not explicitly true for HEG as one of the HRMA mirror shell is
- 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:
so that the extraction region is centered around the tg_d value = 0.0 deg
(see Figure 6 below):
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.
The next section demonstrates the validity of the LSF library.
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.