JWST MIRI Imaging Processing: Lessons from EROs

Transcript

1. MIRI Imaging Processing Lessons from EROs Karl D. Gordon STScI, Baltimore, MD USA MIRI Instrument Team 20 June 2022 kgordon@stsci.edu @karllark2000 karllark@github
2. Workflow • Run detector1 – Fix bug in creation of rate files from rateints files – Bug seen around saturated regions • Run image2 • Update the WCS based on tweakreg results on shortest wavelength filter (see following slide) • For “sparse” targets: create average sky and subtract (see following slide) • Run image3 – Background matching turned off – Not needed and causes issues around mosaic when on – Tweakreg off
3. Astrometry workflow • Shortest wavelength filter – Run image3 with tweakreg including align_to_gaia – Highest precision astrometry as the most stars detected • Analyze tweakreg results based on optional output – Determine average x,y shifts per mosaic tile • All filters taken together for each mosaic tile – All share the same guide star and show the same shifts • Apply the tile average x,y shifts to all filters • Results in sharp stars and well aligned mosaics
4. Example Astrometric Shifts F770W LMC Flat Region
5. Misaligned Tile in Mosaic
6. Sky Subtraction Workflow • For targets that are sufficiently sparse • Create a sigma clipped (+1, -3 sigma) average in pixel coordinates – Option to automatically clip pixels above some threshold – Option to automatically exclude ds9 defined regions • Subtract average sky from each image • Removes – Residual instrumental structure – Scattered light off edges (including Lyot and knife edge) – Long lived latents
7. Reference Files • Reset Anomoly: 09.00.05, Jane derived • Dark: 09.01.00, Jane derived • Linearity: 09.00.09, Jane derived – F2550W: 09.00.06 (specific for this filter) • Flats: 09.02.01, Ors derived – Remove 8 cols/rows around array
8. Example: LMC Flat Region
9. F560W
10. F770W
11. F1000W
12. F1130W
13. F1280W
14. F1500W
15. F1800W
16. F2100W
17. F2550W
18. F1000W, F770W, F560W (highest res)
19. F1280W, F1130W, F770W Aromatic/PAH Features
20. F1280W, F1000W, F560W Grean Galaxies!
21. F1800W, F1000W, F560W Red Galaxies!
22. F2100W, F1800W, F1500W Dust Continuum