Mid Infrared Spectroscopic Standards: Observations and Models

Abstract

We present high precision N-band spectroscopy of a subsample of ESO mid infrared (MIR) calibration standard stars. The spectra were taken with the TIMMI2 instrument at the ESO/La Silla observatory. The low resolution spectra (R ≈ 160) were analyzed with an optimal extraction procedure specifically designed for TIMMI2 spectroscopy. The wavelength calibration was done using atmospheric lines. Our analysis package is based on IDL and will be made available to the community. We compare the spectro-photometric flux of the 1d-spectra to the spectral irradiance calibration models by Cohen et al. (1999). This allows us to demonstrate that the derived absolute calibration of the spectra is accurate to better than 5% in most cases. Our subsample of MIR calibration standards presented here shall become the primary calibrators of the VISIR instrument.