Instruments
MOIRCS
Spectrograph
MOIRCS Sky Spectra
Wavelength calibration
The straight-through wavelengths are 1.12 um for zJ500 and 1.93 um for HK500. The value for R1300 grism is 1.135 um for J, 1.502 um for H, and 2.240 um K, respectively. The following formulae are the result of the fit for the wavelength as a function of pixel (x) for the grisms (Tokoku 2007, Ph.D. thesis). In Channel 2, the dispersion direction of spectra is inversed (Please refer to the MOS page). The formula for R1300-J will be determined soon.
Note that the relation will change with the position of slits.
| zJ500 grism : | 9 × 10-8 x3 - 1 × 10-4 x2 - 5.57 x + 17216 (for Channel 1) |
| HK500 grism : | 1 × 10-7 x3 - 3 × 10-4 x2 - 7.72 x + 27710 (for Channel 1) |
| J+R1300 grism : | TBD |
| H+R1300 grism : | -1.154 × 10-10 x3 + 6.074 × 10-5 x2 + 2.448 x + 13431 (for Channel 2) |
| K+R1300 grism : | -1.091 × 10-9 x3 + 8.651 × 10-5 x2 + 3.758 x + 17461 (for Channel 2) |
Figure 6: Example of the pixel-wavelength relation (Tokoku 2007, Ph.D. Thesis) for Channel 1.
Night Sky Spectra for R500 Grating
The following figures (Figure 7a and 7b) show the night sky emission lines taken by zJ500(7a) and HK500(7b) grisms with 0.3'' slit (channel 1). These figures are from the data taken at 30 Aug, 2006 (after refurbishment for stray-light suppression: see information section). |
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Figure 7: OH Night-Sky Spectra for zJ500 (Fig.7a: upper) and HK500 (Fig.7b: lower), respectively. The bottom horizontal axis indicates the wavelengths [A] and the upper horizontal axis indicates the relative distances from the straight-through wavelenghths (slit position) in pixels. Longslit with 0."3 widths were used. Note that the sky count level will change propotional to the slit width used. Some fraction of the sky counts may come from the scattered stray-light.
Night Sky Spectra for R1300 Grating
The following figure shows the example of the night sky emission lines taken by R1300 grism with 0.8'' longslit. Note that the spectra shown here is from the data before the install of the stray-light suppression mechanism. |  |
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Figure 8: Night-sky spectra for R1300 grating for H (upper) and K (lower) bands. The bottom horizontal axis indicates wavelengths [A], and the vetical axis show the count level per seconds (per pixel) under 0.8" slit. The J-band atlas will be available in the future (TBD). Note that the low-level stray light component (~1 ADU/sec level) is still seen at the wavelength longer than 2.45um.
Please note that all data on these pages are subject to change as the evaluation of the performance of MOIRCS progresses.
Created by Yuka Katsuno Uchimoto (Mar 2006)
Updated by Ichi Tanaka (2008-02-06).