Re-calibration of IRAS flux measurements at 25, 60 and 100 μm using stellar atmosphere models

Abstract

Beam profiles from the Infrared Astronomical Satellite (IRAS) at 60 and 100μm and for both hot and cold sources are analyzed using Fourier techniques to check the efficiency of the short wavelength blockage in the 60 and 100μm filters. Comparison of these power spectra with the expected passbands and an estimate of the noise supports the hypothesis that the 100μm filters have a short wavelength leak of 14.3 ± 3.6%, but that there is no detectable leak in the 60μm filters. Following decrement of the 100μm flux by 14.3%, stellar atmosphere models are anchored at 12μm to the IRAS flux measurements for 33 chosen stars and predicted flux measurements at 25, 60 and 100μm are computed. Comparison of these predictions with those measured by IRAS shows that the IRAS measurements are overestimated at 25 and 60μm and underestimated at 100μm with regard to atmospheric models.