DC2-observation-systematics

This repository contains codes and notebooks to look at the correlation between observational systematics and galaxy photometry and mean redshifts.

A more detailed documentation as well as various results can be found in this Overleaf note: https://www.overleaf.com/read/vjtwzsrmshzm

The codes folder contains some functions used for the analysis.

measure_properties_with_systematics.py contains some customised functions to loop over the tracts and selet data depending on the selected pixels given the systematics map. There is also a function to de-redden the galaxy magnitudes.
run_prop.py can be run to generate Fig.6 - 12 in the documentation.
Dependences: Systematic maps: You can find the MAF maps on NERSC: /global/cscratch1/sd/qhang/minion_1016/MAF-[1/5/10]year/. Alternatively, these maps can be generated following the notebook: DESC_DC2_minion_1016.ipynb. Notice that to run this the rubin package needs to be installed: rubin_sim.
Dependences: DC2 objects: For the DC2 catalogues with some basic cuts and mag_i_cModel<25.3, the files can be found here: /global/cscratch1/sd/qhang/DESC_DC2_obs-dr[2/6]/. Alternatively you can simply access through GCRCatalogs (this is included in the DESC-python environment), following e.g. DC2_download_obj_with_pz-dr6.ipynb.

The notebooks folder contains the Jupyter notebooks used to generate some of the result plots.

DESC_DC2_minion_1016.ipynb generates the MAF maps.
DC2_download_obj_with_pz-dr6.ipynb downloads catalogues of DC2 objects with simple selection and mag_i_cModel<25.3.
DC2_match_OpSim-dr6-multibands.ipynb visualise the systematic maps and shows example corelations with magnitude error and mean photo-z.
DC2_galnum_density-dr6-multibands.ipynb looks at the correlation between systematics and galaxy number density near the $i$ band detection limit.
Compare_MAF_supreme.ipynb compares the MAF and supreme maps.
test_BPZ_run22i.ipynb is an example notebook to estimate photo-z on a subsample of DC2 objects using BPZ_lite. This is used for the dr2 data.

For more questions contact e.hang@ucl.ac.uk.

lsst-uk/DC2-observation-systematics