FUV Grating G130M

Description

The G130M grating samples wavelengths between about 1150 and 1450 Å. (Its use at shorter wavelengths is discussed below.) It offers higher resolution and effective area than the G140L grating, but less spectral coverage.

Special Considerations

The gap between segments A and B spans 14.3 Å. To fill this gap requires exposures separated by two central-wavelength settings.

Grating	Resolving Power R = λ/Δλ	Dispersion (mÅ pixel–1)	Plate Scale (milliarcsec pixel-1)		FP-POS Step (Å step-1)
			Disp. Axis	Cross-Disp. Axis
G130M	16,000 - 21,000	9.97	22.9	100	2.5

Figure 13.1: Wavelength Ranges for the G130M Grating

G130M Point-Source Sensitivity

Table 13.3: G130M Point-Source Sensitivity for PSA

Wavelength (Å)	Throughput	Sensitivity (counts pixel-1 sec-1 per erg cm-2 sec-1 Å-1)	Effective Area (cm2)
1150	3.230E-02	8.4E+11	1.46E+03
1200	4.530E-02	1.2E+12	2.05E+03
1250	5.643E-02	1.6E+12	2.55E+03
1300	5.235E-02	1.5E+12	2.37E+03
1350	4.406E-02	1.3E+12	1.99E+03
1400	3.814E-02	1.2E+12	1.73E+03
1450	2.917E-02	9.6E+11	1.32E+03

Figure 13.2: G130M Point-Source Sensitivity for PSA and BOA

The throughput of the BOA is poorly characterized below 1200 Å and close to zero below 1150 Å.

G130M Signal-to-Noise Ratio

Figure 13.3: Point-Source Signal-to-Noise as a Function of STMAG for G130M at
1310 Å

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 Å-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.