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GNIRS + GCAL Arc Lamp Identifications

The following table shows a summary of GCAL emission line plots for two lamps (Ar and Xe) at near IR wavelengths. The spectra all have the same integration time. Wavelengths are in vacuum. See also the general wavelength calibration page for more line lists etc.

In general, the Argon lamp will be sufficient for wavelength calibration in most GNIRS observing modes. However, for the long camera / 111 grating case (R=18,000 mode), you may need to take supplementary Xenon lamp observations at wavelengths where the Argon lines are sparse. Check the plots below to verify this.

Note: The wavelength range in each of the plots below is equivalent to the coverage delivered by the short camera / 111 grating mode (R=6000), and 3 times the spectral window of the long/111 mode. The Argon lamp is sufficient for all arc lamp calibrations when using the 32 l/mm grating.


Waveband Wavelength Range (microns) GCAL Arc Lamp Plots
J 1.046 - 1.143 Argon Xenon
J 1.142 - 1.246 Argon Xenon
J 1.242 - 1.379 Argon Xenon
H 1.471 - 1.598 Argon Xenon
H 1.592 - 1.728 Argon Xenon
H 1.723 - 1.813 Argon Xenon
K 1.962 - 2.078 Argon Xenon
K 2.070 - 2.242 Argon Xenon
K 2.233 - 2.399 Argon Xenon

For convenience, the following plots show the observed lamps and line identifications for orders 3 through 8 of the cross-dispersed 32l/mm grating mode (XD32).


Order Approx. Wavelength Range (microns) GCAL Arc Lamp Plots
3 1.88 - 2.52 postscript
4 1.41 - 1.90 postscript
5 1.13 - 1.51 postscript
6 0.95 - 1.25 postscript
7 0.90 - 1.06 postscript
8 0.72 - 0.95 (signal very weak <  0.9) postscript

Last update June 24, 2005; Bernadette Rodgers