struct ARF {
long NumberEnergyBins; /* Number of response energies */
float* LowEnergy; /*NumberEnergyBins*/ /* Start energy of bin */
float* HighEnergy; /*NumberEnergyBins*/ /* End energy of bin */
float* EffArea; /*NumberEnergyBins*/ /* Effective areas */
char EnergyUnits[FLEN_KEYWORD]; /* Units for energies */
char arfUnits[FLEN_KEYWORD]; /* Units for effective areas */
char Telescope[FLEN_KEYWORD];
char Instrument[FLEN_KEYWORD];
char Detector[FLEN_KEYWORD];
char Filter[FLEN_KEYWORD];
char ARFExtensionName[FLEN_VALUE]; /* EXTNAME keyword in SPECRESP */
};