MIRI Bright Source Limits
Bright source limits of JWST's Mid-Infrared Instrument (MIRI) are derived from in-flight measurements.
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The performance of MIRI has been measured directly at both the component and system level using the fully assembled MIRI flight model in a flight-like radiative environment with a well characterized radiometric source (Glasse et al. 2015). Results of these JWST throughput measurements have been integrated into a sensitivity model, which includes the following components: (1) background, (2) photon conversion efficiency (PCD), (3) encircled energy, and (4) detector performance (Pontoppidan 2016).
The values in the table and plots below were obtained from ETC 3.0.
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Imager
Table 1.MIRI imager bright source limits (for Ngroups = 5)
| Filter | Full Frame (mJy) | SUB64 subarray (mJy) |
|---|---|---|
| F560W | 3.48 | 113.51 |
| F770W | 2.93 | 96.17 |
| F1000W | 5.38 | 177.64 |
| F1130W | 20.98 | 687.75 |
| F1280W | 10.10 | 336.03 |
| F1500W | 11.46 | 388.32 |
| F1800W | 19.34 | 671.29 |
| F2100W | 21.85 | 831.10 |
| F2550W | 43.41 | 2067.84 |
Table 2.MIRI imager subarray bright source limits (for Ngroups = 5)
| Subarray | Brightness limit in F560W (mJy) | Brightness limit in F2550W (mJy) |
|---|---|---|
FULL | 3.48 | 43.41 |
BRIGHTSKY | 11.16 | 184.80 |
SUB256 | 32.25 | 572.88 |
SUB128 | 81.16 | 1472.73 |
SUB64 | 133.51 | 2067.84 |
References
Glasse, A., et al. 2015, PASP, 127, 686
The Mid-Infrared Instrument for the James Webb Space Telescope, IX: Predicted Sensitivity
Pontoppidan, K. 2016, Proc of SPIE, 9910, 16
Pandeia: a multi-mission exposure time calculator for JWST and WFIRST