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2. The Problem

The SWS and the IDC have been contacted by the STARTYPE group (S.D. Price, G. Sloan and K. Kraemer) at the Air Force Research Laboratory about systematic problems with their spectra based on OLP10 data. The problems they describe are emission features of $\sim$ 4-6% in SWS AOT bands 2A and 2C and a systematic slope of $\sim$ 2% across band 2B in stars where such features are non-physical. Furthermore, the shape of the features are suggestive of the CO fundamental at 4.3-5.5 $\mu$ m and the SiO fundamental at 8-11 $\mu$ m. Figure 1 shows the mean ratio from 2.3 to 11.5 $\mu$ m of stars processed with the STARTYPE post AAR processing and the Cohen et al. absolutely calibrated composite spectra [1,2,3] of a sample of stars in the SWS database [6]. The STARTYPE group interprets the systematic differences between composite spectra by Cohen and the result of their processing of SWS spectra as deficiencies in the late-type star synthetic spectra by Decin ([5]) used for the OLP 10 RSRF calibration [8] and absolute photometric calibration [7]. However the problem is not so transparent. It should be noted, that the original validation report of L. Decin for OLP 10 also discusses some of the same RSRF problems as described in this note. It is unfortunate that these earlier warnings went unheeded.

**Figure 1:** A sample of stars processed with OLP10 calibration and STARTYPE post processing ratioed to Cohen absolutely calibrated spectra of same the stars [6].
$\resizebox {\hsize}{!}{\includegraphics{sloanfig5.ps}}$

Next: 3. Analysis Up: olp101sws Previous: 1. Introduction

Improvements in the OLP 10 RSRF and Flux Calibration of ISO-SWS Bands 2A and 2C

ISO Explanatory Library: SWS

2. The Problem