1. Optimization Strategies for the NIRSpec MSA Planning Tool James Muzerolle

2. Special thanks to NIRSpec teamlet members and APT developers: Diane Karakla Tracy Beck Jason Tumlinson Jeff Valenti Tom Donaldson Rob Douglas Karla Peterson

3. Quick NIRSpec overview 3 spectroscopic modes: MOS, fixed slit, IFU 3 resolutions: R ~ 100 (prism), 1000 and 2700 (gratings) effective wavelength range 0.6 – 5 microns FOV ~ 3.6’ x 3.4’

4. Microshutter Array (MSA) 4 x 365 x 171 shutters, individually addressable shutter pitch = 0.26” x 0.51”, (actual FOV = 0.2” x 0.45”) activated with magnet sweep

5. prism spectral layout R=2700 spectral layout

6. MSA planning tool prototype (APT v17.0.3)

7. Preliminary optimization study IDL code to simulate planning tool analysis of target placement within MSA shutters heuristic iterative scheme to optimize the number of targets per MSA configuration from an input “candidate” target sample –grid of MSA center pointings and position angles –optimized solution = grid point with largest number of targets –loop for multiple configurations test cases to evaluate various parameters: –input sample size/spatial distribution –number of “sky” shutters –including known failed shutters –dithers –target priorities

8. # candTarg Set 1Targ 1/2Config 1/2Fails?Test case 1009102407 5 n1 center 10091025346n3x3 center grid, 3-shutter slitlets 1009805088y 10091185055y2-shutter slitlets 1009765459yshutter dither (0.26”) 10096551011ygap dither (17.9”) 10006451911yconcentrated source distribution 259162ysparse sample, 3 orients 1009 (99, 100)71 (24, 11)528 (88, 76)8ytarget priorities Optimization results

9. Default test case: UDF-derived input candidate target catalog (1009 objects) 3x3 center pointing grid, 20.1” x 36.2” offsets 3-shutter slitlet ideal MSA 1 configuration per target set (no cross-slitlet dithers)

10. # candTarg Set 1Targ 1/2Config 1/2Fails?Test case 1009102407 5 n1 center 10091025346n 3x3 center grid, 3-shutter slitlets 1009805088y 10091185055y2-shutter slitlets 1009765459yshutter dither (0.26”) 10096551011ygap dither (17.9”) 10006451911yconcentrated source distribution 259162ysparse sample, 3 orients 1009 (99, 100)71 (24, 11)528 (88, 76)8ytarget priorities Optimization results

11. Default test case with failed shutters

12. # candTarg Set 1Targ 1/2Config 1/2Fails?Test case 1009102407 5 n1 center 10091025346n3x3 center grid, 3-shutter slitlets 1009805088y 10091185055y2-shutter slitlets 1009765459yshutter dither (0.26”) 10096551011ygap dither (17.9”) 10006451911yconcentrated source distribution 259162ysparse sample, 3 orients 1009 (99, 100)71 (24, 11)528 (88, 76)8ytarget priorities Optimization results

13. Default test case with failed shutters, 2-shutter slitlet

14. # candTarg Set 1Targ 1/2Config 1/2Fails?Test case 1009102407 5 n1 center 10091025346n3x3 center grid, 3-shutter slitlets 1009805088y 10091185055y 2-shutter slitlets 1009765459yshutter dither (0.26”) 10096551011ygap dither (17.9”) 10006451911yconcentrated source distribution 259162ysparse sample, 3 orients 1009 (99, 100)71 (24, 11)528 (88, 76)8ytarget priorities Optimization results

15. Default test case with failed shutters, 1-shutter dither (0.26”) in dispersion direction

16. # candTarg Set 1Targ 1/2Config 1/2Fails?Test case 1009102407 5 n1 center 10091025346n3x3 center grid, 3-shutter slitlets 1009805088y 10091185055y2-shutter slitlets 1009765459y shutter dither (0.26”) 10096551011ygap dither (17.9”) 10006451911yconcentrated source distribution 259162ysparse sample, 3 orients 1009 (99, 100)71 (24, 11)528 (88, 76)8ytarget priorities Optimization results

17. Default test case with failed shutters, detector gap dither (18”)

18. prism spectral layout R=2700 spectral layout

19. # candTarg Set 1Targ 1/2Config 1/2Fails?Test case 1009102407 5 n1 center 10091025346n3x3 center grid, 3-shutter slitlets 1009805088y 10091185055y2-shutter slitlets 1009765459yshutter dither (0.26”) 10096551011y gap dither (17.9”) 10006451911yconcentrated source distribution 259162ysparse sample, 3 orients 1009 (99, 100)71 (24, 11)528 (88, 76)8ytarget priorities Optimization results

20. # candTarg Set 1Targ 1/2Config 1/2Fails?Test case 1009102407 5 n1 center 10091025346n3x3 center grid, 3-shutter slitlets 1009805088y 10091185055y2-shutter slitlets 1009765459yshutter dither (0.26”) 10096551011ygap dither (17.9”) 10006451911yconcentrated source distribution 259162ysparse sample, 3 orients 1009 (99, 100)71 (24, 11)528 (88, 76)8ytarget priorities Optimization results

21. Recommendations Tool should incorporate iterative scheme for optimizing the number of targets in a configuration using a grid of center pointings and/or position angles. Account for “acceptance zone” where flux losses are minimized. Failed shutters must be tracked and updated. No targets in failed closed. Generate warnings for targets in rows with failed opens. Include an option for dithers requiring separate configurations (e.g., detector gap coverage), for an arbitrary number of dithers. Target priorities, with an arbitrary number of layers, should be a key part of the optimization scheme. Include a diagnostic plot summarizing characteristics of all targets in a given configuration, such as relative shutter position, priority, dither status, user-defined properties (magnitude, redshift, etc).

22. To do optical distortion across the FOV must be included, with the ability to update the distortion solution as needed better treatment of prism spectra (can fit more than one in the same shutter row without overlap) target acquisition: visualization and selection of reference stars, avoiding failed closed shutters explore more observing scenarios