A general tool for simulating NIRSpec
MSA observations
Klaus Pontoppidan
With contributions from Diane Karakla, Jeff Valenti, the NIRSpec teamlet and
the APT MSA team: Andy Spina, Sasha Shyrokov and Karla Peterson.
MSA Basics
210”
171 shutters
Detector FOV
365 shutters
Rationale
Develop and quantify APT MSA tool algorithms.
Generate simulated end-to-end operational concepts
for real use cases.
Create realistic test data for high level data pipeline
development (point source/extended source
extraction, background subtraction, spoiler
mitigation, CR/bad pixel mitigation, ...)
ETC verification (in conjunction with a detector
simulator).
Scope: MCselect flow chart
Generate simulated
cluster
Features
Import tabulated cluster
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- Hubble Ultra Deep Field
- Carina cluster
- etc...
- Spatial distribution
- Flux distribution
- Size distribution
Monte Carlo loop
Reorder candidate list
Candidate list structure
Generate MSA config
MSA config structure
Exposure simulator
- Point/compact source emission
- Background emission
- Noise
Assign shutters based on a
random candidate list order
Target acquisition
image
Confirmation image
Spectral image
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Input
Output
External software
Detector artifacts
simulator
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Data reduction/
Extraction pipeline
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Monte Carlo solution for maximizing
optimization scores
Scriptable operations
Simulated and real cluster catalogs
Optical distortion
Arbitrary slitlet patterns
Realistic shutter mask (failed
open/closed)
MSA contrast map-ready
WebbPSFs
2D Extended sources
FM1 wavecals
Blaze functions
Filter curves
Optical train efficiency
MultiAccum noise model
Spectral and MIRROR TA/confirmation
images
Realistic backgrounds
Model spectra including continuum and
emission lines
Modular and extensible code structure
Active development
Use case: the Hubble ultra-deep field
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10176 targets
22 high priority
“z=10” galaxies
How many
configurations
are needed?
5
4
6
8
7
9
2
1
3
~300”
Heat map
10”
400”
Number of targets observed as a function of pointing
1
2
3
4
Visualization of exclusion rates
The exposure simulator
Confirmation image
Simulated spectra: Argon lamp test
Single pointing
Exposure simulation
• Target brightnes: 30-60 nJy
• Low zodi
• Grating: G140M (R=1000)
• Filter: F100LP
• Stack of 500 exposures
• (25 NRS groups each)
Nod pair A-B
LyA @ z=10 (5x10-19 erg/cm2)
Key messages
There is a need for efficient + accurate algorithms for
MSA planning.
We have a general tool for quantifying algorithms.
A potential “baseline” solution exists. Work is
ongoing to produce competing (faster) algorithms.
A detailed exposure simulator is available for testing
high-level data processing of MSA data.