This repository holds the code used by Alan Meert for research in Astrophysics at the University of Pennsylvania. There are many packages here.
To install, make sure that your PYTHONPATH includes the directory holding this repository. Then run the create_user_params.sh script which will create a file called user_settings.py that holds your credentials for MySQL, SDSS CasJobs, and some paths.
A large part of this project is the fitting pipeline for SDSS galaxies. This can be divided into several steps. The steps are outlined below along with the relevant modules in this code.
-
Catalog construction - (see the casjobs_query module) Prior to fitting, a catalog of galaxies is needed. In addition, relevant details about the galaxies are necessary to extract the postage stamp images of each galaxy. An identifying ID number, SDSS run, SDSS rerun, SDSS camCol, SDSS field, band-specific rowc, band-specific colc, and half-light radius are needed for fitting. The ID number is referred as galcount and used throughout the pipeline for record-keeping. The run, rerun, camCol, field specify the image to use for extraction. The rowc and colc specify the pixel coordinates of the center of the galaxy in the image. The half-light radius sets the scale for the size of the cutout. The casjobs_query module is intended to be used to collect this data.
-
Image collection and extraction - (see the cut_pipe module) After collecting the catalog, we need to extract the postage stamp image, construct a weight image, and extract the PSF image. The cut_pipe mdule does this. It downloads the SDSS image frame and SDSS psField file and then extracts the postage stamp, constructs the weight image, and extracts the PSF image.
-
Running the fitting - (see grid_management.job_manager) The stamps have to be fit, the job_manager handles the Pymorph config file construction and running Pymorph. This also assumes that Pymorph, Galfit, and SExtractor are installed on your machine. See the INSTALL.txt file for information on these dependencies.
-
Post-processing of the fits - (see the post_processing module) After fitting, measurement of the non-PSF convolved half-light radius, and profile measurements are made.
-
Flagging - (see the flagging module) Finally the flagging must be run.
There are many other included modules in this codebase. These will be listed here eventually.