25MAMA - FUV-MAMA, Clear

Description

The 25MAMA mode with the FUV-MAMA detector provides high-throughput broad-band far-ultraviolet (FUV) imaging with the highest available throughput at ~1500 Å and the highest possible spatial resolution.

Recommended Uses

Recommended for broad-band NUV imaging of sources where sky background is not a consideration.

Special Considerations

For long exposures of faint targets, sky background is likely to be a limiting factor. Observers should consider the use of DARKTIME or (preferably) use the F25QTZ filter, which has nearly the same throughput but rejects geocoronal Lyman-α and [O I] 1302 + 1306 Å air glow.

Users may also want to consider whether the ACS SBC detector might be better for their observing program.


Pivot λ (Å)

FWHM (Å)

AB mag zero point

Speak

Bλ

R80 (arcsec)

Flux in central pixel

1367.5

316.5

23.457

1.21e+14

341.9

0.32

8%

Figure 14.66: 25MAMA FUV-MAMA Integrated System Throughput and Redleak



Table 14.26: 25MAMA FUV-MAMA Sensitivity & Throughput

λ

Sensitivity

% Throughput

1150.

1.08E13

0.41

1175.

4.69E13

1.75

1200.

8.61E13

3.15

1225.

1.15E14

4.11

1250.

1.21E14

4.24

1275.

1.20E14

4.12

1300.

1.16E14

3.92

1325.

1.12E14

3.70

1350.

1.07E14

3.48

1375.

1.01E14

3.23

1400.

9.44E13

2.96

1425.

8.58E13

2.64

1450.

7.68E13

2.32

1475.

6.77E13

2.02

1500.

5.92E13

1.73

1525.

5.24E13

1.51

1550.

4.64E13

1.31

1575.

4.04E13

1.13

1600.

3.49E13

0.96

1625.

3.08E13

0.83

1650.

2.74E13

0.73

1675.

2.34E13

0.61

1700.

1.94E13

0.50

1725.

1.63E13

0.41

1750.

1.37E13

0.34

1775.

1.14E13

0.28

1800.

9.55E12

0.23

1825.

7.29E12

0.18

1850.

3.76E12

0.09

Figure 14.67: Point Source S/N vs. V+ABν for the 25MAMA FUV-MAMA mode. Curves are labeled by required exposure time (seconds).


Figure 14.68: Extended Source S/N vs. V+ABν for the 25MAMA FUV-MAMA mode. Top curves are for an area of 0.2 arcsec2; bottom curves are for 1 arcsec2. Average sky assumed. Curves are labeled by required exposure time (seconds).



Table 14.27: Radial Profile for 25MAMA*

Radius


 

Fraction of Energy Encircled

Pixels

Arcsec

Intensity

1

0.024

3.267e-02

0.141

1.5

0.037

2.107e-02

0.236

2

0.049

1.345e-02

0.331

3

0.073

6.141e-03

0.467

4

0.098

2.981e-03

0.557

5

0.122

1.485e-03

0.614

10

0.245

3.377e-04

0.746

15

0.367

1.676e-04

0.834

20

0.490

9.542e-05

0.900

25

0.613

4.543e-05

0.947

30

0.735

2.065e-05

0.972

40

0.980

5.088e-06

0.994

* See STIS ISR 2003-01.


Figure 14.69: Point Source Encircled Energy for 25MAMA FUV-MAMA


Figure 14.70: Point Source Intensity vs. Radius for 25MAMA FUV-MAMA