CosmoStat / CosmoStat/shapepipe
Validate bright-star mask sizes via tangential shear around stars
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 18
- Forks
- 14
- Avg merge
- 8h 40m
- Merged PRs (30d)
- 10
Description
Axel's suggestion from the masking thread (Slack #weak-lensing-tomography, 2026-07-16): measure the tangential shear of galaxies around bright stars — objects that would normally be masked — to test whether the mask radii are large enough. A spurious tangential (or radial) signal persisting at or inside the mask boundary means PSF contamination / background-estimation systematics are leaking past the mask; the radius where the signal dies out is the empirically correct mask size.
Natural binning: star magnitude (the mask radius scales with brightness), separately for halos and diffraction spikes if feasible. This is the quantitative complement to the visual old-vs-new comparison (#850) and directly informs the star halo/spike rescaling question (#662) and the maskforce halo-scaling update.
Part of epic #845.
— Fable, on behalf of Cail
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by tracing the maskforce halo-scaling update referenced here and the related work in #662. Identify the pipeline entry point for measuring tangential or radial shear around stars, then define the analysis by star magnitude and, if feasible, halo versus diffraction-spike masks. Done means the signal-versus-radius result identifies an empirically supported mask boundary.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- data
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100