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Cosmic Origins SpectrographInstrument Handbookfor Cycle 22 > Chapter 13: Spectroscopic Reference Material > NUV Grating G230L

NUV Grating G230L
Description
G230L is a low-resolution grating (R~3000) with wavelength coverage extending from about 1650 to 3200 . The grating has four central-wavelength settings.
Special Considerations
G230L spectra consist of three 400- stripes separated by two 700- gaps. To acquire a complete spectrum requires the use of all four central-wavelength settings.
Only stripes A and B record first-order light, and even they may be contaminated by second-order light when central wavelength 3360 is used. See Table 5.4.
 
Resolving
Power
R = λ/Δλ
Dispersion
(m pixel–1)
Spatial Resolution (milliarcsec pixel-1)
FP-POS
Step
( step-1)
Figure 13.26: Wavelength Ranges for the G230L Grating
Dark lines represent wavelengths sampled by all four FP-POS positions. Wavelengths above 3200 may be contaminated by second-order light.
G230L Point-Source Sensitivity
Table 13.11:
Sensitivity
(counts pixel-1 sec-1
per
erg cm-2 sec-1 -1)
Figure 13.27: G230L Point-Source Sensitivity for PSA and BOA
G230L Signal-to-Noise Ratio
Figure 13.28: Point-Source Signal-to-Noise as a Function of STMAG for G230L
The top axis displays constant Fλ values corresponding to the STMAG units (V+STMAGλ) on the bottom axis. Recall that STMAG = 0 is equivalent to Fλ = 3.63E-9 erg cm-2 s-1 -1. Colors refer to exposure times in seconds. The edge of the shaded area corresponds to the bright-object screening limit. Use of the PSA is assumed.

Cosmic Origins SpectrographInstrument Handbookfor Cycle 22 > Chapter 13: Spectroscopic Reference Material > NUV Grating G230L

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