WARNING to those of you using the tool dmarfadd!
If the keywords TG_SCRID or TG_PART are missing from your ARF's (which they
are from mine -- who knows why), then dmarfadd will print error messages, but
will still produce an output file. It turns out that the output file is
simply a copy of the first ARF in your list of ones to add up. Thus one gets
incorrect output, instead of the preferred no output at all.
I intend to stick to the well-behaved FTOOL addarf for the time being. Addarf
is also more flexible, allowing you to average ARFs instead of adding them --
something very useful if you care to worry about the fact that real sources
are extracted over a finite region of the detector (which might include a chip
gap where the effective area is changing on scales of 10's of pixels), whereas
mkarf computes an ARF for a single point on the sky.
Regards,
Patrick Broos
-- ==================================================================== Patrick S. Broos, Systems Analyst/Programmer patb@astro.psu.eduDepartment of Astronomy and Astrophysics My office 814-863-7947 Penn State University 525 Davey Lab FAX 814-863-8686 University Park, PA 16802-6305 http://www.astro.psu.edu Group office 863-9550 ====================================================================
This archive was generated by hypermail 2b29 : Wed May 15 2013 - 01:00:03 EDT