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C.1 Application of Tabulated Colour Correction Factors

The flux densities quoted in the ISOPHOT AAR results have been derived from the detector in-band powers assuming an energy distribution of the source which is constant in the flux per logarithmic frequency interval; i.e., the flux density with frequency $\nu$ goes as $f_{\rm \nu} \propto \nu^{-1}$ . This is the same convention as used for IRAS data.

In order to derive the flux density for any other spectral energy distribution (SED) a ``colour correction'' must be applied to the background subtracted source flux density in the following way:

$\begin{displaymath} F_{\rm \nu_{\rm ref}}(SED) = F_{\rm \nu_{\rm ref}}(\nu^{-1})~/~K_{\rm cc}(SED)\end{displaymath}$ (C.1)

where:


 = flux density for applied SED
 = quoted flux density in AAR
 = tabulated colour correction factor for applied SED

Tabulated colour correction factors are available for

1): power laws $F(\nu^{\alpha}), -3~\le~\alpha~\le~+3$
$\rightarrow$ cal-G file PCCPOWER
2): black bodies $F(B(\nu,T))$
$\rightarrow$ cal-G file PCCB
3): modified black bodies $F(\nu^{+1} \cdot B(\nu,T))$ and $F(\nu^{+2} \cdot B(\nu,T))$
$\rightarrow$ cal-G files PCCMBBONE and PCCMBBTWO

ISOPHOT Data Users Manual, Version 4.1, SAI/95-220/Dc