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Cosmic Origins SpectrographInstrument Handbookfor Cycle 22 > Chapter 13: Spectroscopic Reference Material > NUV Grating G225M

NUV Grating G225M
Description
The G225M grating samples wavelengths between about 2100 and 2500 . The grating has 13 central wavelength settings.
Special Considerations
G225M spectra consist of three 35 stripes separated by two 64 gaps. To acquire a complete spectrum requires the use of six central-wavelength settings.
 
Resolving
Power
R = λ/Δλ
Dispersion
(m pixel–1)
Spatial Resolution (milliarcsec pixel-1)
FP-POS
Step
( step-1)
Figure 13.20: Wavelength Ranges for the G225M Grating
Dark lines represent wavelengths sampled by all four FP-POS positions.
G225M Point-Source Sensitivity
Table 13.9: G225M Point-Source Sensitivity for PSA
Sensitivity
(counts pixel-1 sec-1 per
erg cm-2 sec-1 -1)
Figure 13.21: G225M Point-Source Sensitivity for PSA and BOA
G225M Signal-to-Noise Ratio
Figure 13.22: Point-Source Signal-to-Noise as a Function of STMAG for G225M
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 G225M

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