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Defining the spectral model

Model expression are built using the various functions listed in the spf documentation and summarised in table 7, and the arithmetic operators +, -, * and /, using parenthesis as appropriate. For example,

qcl>SPF_MODEL = '(PLAW(1,2) + BBOD(3,4)) * ABSO(5)

The model expression can be expanded to two input lines by termainating the string expression for SPF_MODEL by an & at an appropriate position (i.e. before or after a complete model term) and by setting the parameter SPF_MODEL_& to the remaining terms. For example,

qcl>SPF_MODEL = '(PLAW(1,2) + BBOD(3,4)) & 
qcl>SPF_MODEL_& = ' * ABSO(5)

Note that all energies are in the rest frame of the source except for grain scattering. If the parameter SPF_REDSHIFT > 0 then the source spectrum will be appropriately shifted including the intrinsic absorption profile set by the function ABSI. The absorption profile imposed by the function ABSO is used on the redshifted result and therefore is appropriate for the column density in our galaxy.


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