15.3 RMFs and ARFs
An RMF (Response Matrix File) is logically a 2-d array which gives for each
input photon energy the probability of assigning the photon to a given PHA channel.
An ARF (Ancillary Response File) is logically a 1-d array, indexed on input photon
energy, which contains all other contributions to the effective area. This may need
to be calculated more often, since it may depend on instrument setting, position in the FOV, etc.
In practice the RMF file can be a pure RMF (contains an adimensional probability), or
can contain the product of the RMF and the ARF.
XAS users have the option of producing separately RMFs, ARFs or both. This interacts
with the choice of
matrix format as follows :
- if the OGIP format is selected
- the RMF (always a pure RMF) is produced only if rmffile is not
equal to "none"
- the ARF is produced only if arffile is not
equal to "none"
- both are produced if both filenames are given
- if the XAS format is selected
- the rmffile argument must always be specified
- no separate ARF is produced in any case
- if arffile is equal to "none", the matrix file
in XAS format contains the pure RMF.
- if arffile is any other value, its name is ignored, but
the matrix file in XAS format contains the product of the RMF, the ARF and the input
energy bin width (i.e. has a dimension of cm2 keV)
sax.iasf-milano.inaf.it/Xashelp/maccum.3.html
:: original creation 2002 Sep 04 17:48:29 CEST ::
last edit 2002 Sep 04 17:48:29 CEST