This repo hosts the mock galaxy catalogs availble to the LSST DESC and are used by DESCQA. The GCRCatalogs module uses the "Generic Catalog Reader" (GCR) to provide a unified interface to access these catalogs. More information about GCR can be found in the GCR repo. Description of the concept of this reader interface can be found in the DESCQA paper.

Currently these sets of catalogs are available (Note that these catalogs are not perfect and will continue to be updated):

1. protoDC2: by Andrew Benson, Andrew Hearin, Katrin Heitmann, Danila Korytov, Eve Kovacs et al.

   • protoDC2 (full catalog)
   • protoDC2_test (same as protoDC2 but this one skips time-consuming md5 check.)

2. Buzzard series: by Joe DeRose, Risa Wechsler, Eli Rykoff et al.

   • buzzard (full catalog, DES Y3 area)
   • buzzard_test (same as buzzard but a small subset for testing purpose)
   • buzzard_high-res (higher resolution, smaller sky area)
   • buzzard_v1.6_1, buzzard_v1.6_2, buzzard_v1.6_3, buzzard_v1.6_5, buzzard_v1.6_21 (different realizations of buzzard)

3. DC1 catalog:

   • dc1

Each of the catalogs is specified by a YAML config file, which can be found here. The galaxy quantities in these catalogs conform to the schema.

Note: These instructions about Python environment may change in the future. If you encounter issues, please check if there's any updates on these instructions.

GCRCatalogs is already installed in the DESCQA Python envoirnment at NERSC. To use it:

First, start a NERSC notebook server and open a notebook with a Python kernel. In the first cell, insert the Python enviornment to sys.path:

For Python 3 (recommended):

import sys
sys.path.insert(0, '/global/common/software/lsst/common/miniconda/current/lib/python3.6/site-packages')

For Python 2:

import sys
sys.path.insert(0, '/global/common/cori/contrib/lsst/apps/anaconda/py2-envs/DESCQA/lib/python2.7/site-packages')

Activate DESCQA Python environment by running the following on NERSC (needs to be in bash or zsh):

For Python 3 (recommended):

source /global/common/software/lsst/common/miniconda/setup_current_python.sh

For Python 2:

source /global/common/cori/contrib/lsst/apps/anaconda/4.4.0-py2/bin/activate
source activate DESCQA

To be able to import GCRCatalogs, the first line of the script should be:

For Python 3 (recommended):

#!/global/common/software/lsst/common/miniconda/current/bin/python

For Python 2:

#!/global/common/cori/contrib/lsst/apps/anaconda/py2-envs/DESCQA/bin/python 

If you need to use a newer version of GCRCatalogs then the one installed on NERSC, you can clone this repo (on a NERSC machine), and add the path to sys.path. You should add this line right after you insert the DESC Python environment.

sys.path.insert(0, '/path/to/gcr-catalogs')

• See this notebook for a detail tutorial on how to use GCR Catalogs.

• See this notebook for an actual application (the Conditional Luminosity Function test) using GCR Catalogs. (Thanks to Joe DeRose for providing the CLF test example!)

• See GCR documentation for the complete GCR API.