Introduction

This document provides Argon and Xenon line lists and plots for wavelength calibration of ISAAC data.

It is reminded that due to non perfect reproducibility of the ISAAC grating, it is recommended to use the OH lines for wavelength calibration of the science data in the SW domain. In the LW domain, half cycle frames also provide an intrinsic way of calibrating science data with the atmospheric absorption lines seen in emission against the thermal background, but no detailed atlas of these lines is available yet. Therefore, in the LW domain, wavelength calibration has to resort to arc frames, with the material provided below. Only in the L band (SL filter) are arc lines detectable. In part of the L band, and in the M band, there are no observable lines, and wavelength calibration has to be done with higher orders in the SW domain, and linearly scaling the wavelength dispersion solution according to:

$$\lambda_{lw} = k_{sw} \times \lambda_{sw}$$

using the following table:

 

Table 1: SW order versus wavelength for higher order wavelength calibration in the M band.

$\lambda_{sw}$ range (microns)	ksw
[0.83-0.97]	6
[0.98-1.10]	5
[1.10-1.40]	4
[1.40-1.82]	3
[1.82-2.50]	2