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cta-observatory / magic-cta-pipe

Pipeline for the analysis of MAGIC and LST1 data, and more.
https://magic-cta-pipe.readthedocs.io/
BSD 3-Clause "New" or "Revised" License
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Non-consistent calculation of concentration parameters #256

Open jsitarek opened 2 months ago

jsitarek commented 2 months ago

concentration parameters for MAGIC are computed from non cleaned image: https://github.com/cta-observatory/magic-cta-pipe/blob/01f273d656d9a440ef43802b30aa25a99975d889/magicctapipe/scripts/lst1_magic/magic_calib_to_dl1.py#L291

same is done for MCs (both MAGIC and LST-1): https://github.com/cta-observatory/magic-cta-pipe/blob/01f273d656d9a440ef43802b30aa25a99975d889/magicctapipe/scripts/lst1_magic/lst1_magic_mc_dl0_to_dl1.py#L328-L330

however for LST this is done after selecting only image pixels: https://github.com/cta-observatory/cta-lstchain/blob/e4a5b7a36dfd643acf47b9006f51fe882b6dbc5c/lstchain/reco/r0_to_dl1.py#L164

the difference is not huge, but especially if there are multiple islands the concentration parameters can behave in complicated way.

Thankfully the concentration parameters are not used in the standard chain.

There are two possible ways to fix it: 1) change both for MAGIC data and for MC to have it the same as for LST-1 data 2) change the behavior for LST-1 MCs to reproduce what is done in the data (which would mean that the parameter would have slightly different meaning for different telescopes)

jsitarek commented 2 months ago

this is the difference between the values of the parameters for the data between LST data (computed from the cleaned image in blue and from full image in orange: conc2 (computed by @nzywucka )