causticsnupy 1.0.2

Python package for determining cluster members using caustic technique.

CausticSNUpy

Python module for drawing caustic lines and determining cluster membership of galaxies using the caustic technique presented in Diaferio (1999) and Serra et al. (2011).

CausticApp, a program written by Serra and Diaferio, was used as a benchmark for this module and thus we tried to reproduce the same output for a given input.

Details of this code can be found in Kang et al. (2024).

Citation

We kindly request you to cite the following paper if you used this code:

Kang, W., Hwang, H. S., Song, H., et al. 2024

Dependencies

Required Packages

• NumPy
• SciPy
• astropy
• scikit-image

Tested with:

• Python 3.9.7
• numpy 1.20.3
• scipy 1.7.1
• astropy 4.3.1
• scikit-image 0.18.3

How to install

This package is currently only available through manual installation.
After downloading and the tar.gz file, follow one of the following methods.

Method 1: using pip

1. Open terminal and change directory to where tar.gz file is located.
2. Type and run pip install + tar.gz file name.

pip install CausticSNUpy-<version>.tar.gz

Method 2: run setup.py

1. Open terminal and change directory to where setup.py is located.
2. In your terminal, type and run

python setup.py install

3. Now you are ready to use this package!

How to uninstall

1. Open terminal (any directory is fine).
2. In your terminal, type and run

pip uninstall CausticSNUpy

How to use

Input file

If you are using run_from_file, the input file must follow the following format:

• The first line of the input file may either have 1 or 4 numbers.
  • The first line should be in format N or N RA DEC VEL, where N is the number of galaxies in the data, RA and DEC are the right ascension and declination of the cluster center (both in deg), and VEL is the radial velocity of the cluster center (in km/s).
  • If RA, DEC, VEL are not given, input parameter center_given should be set to False.
  • If N does not match the number of galaxies listed, the program will emit and error.
• Input file must have 3 columns (except for the first line, as mentioned above).
  • Each line is in format RA DEC VEL. RA and DEC are the right ascension and declination of each galaxy (both in deg), and VEL is the radial velocity of each galaxy (in km/s).

Routine

See example.ipynb for the code to set the parameters, run the caustic method, and plot the redshift diagram with caustic lines.

Main attributes of the class

• r : projected distance from the cluster center to each galaxy [Mpc]
• v : relative (with regard to the cluster center) l.o.s. velocity of each galaxy [km/s]
• r_grid : grid along the r-axis of the redshift diagram [Mpc]
• A : amplitude of the caustic lines along r_grid [km/s]
• dA : uncertainty in A [km/s]
• M : enclosed mass profile along r_grid [$M_{\odot}$]
• dM : uncertainty in M [$M_{\odot}$]

References

1. Diaferio, A. 1999, MNRAS, 309, 610
2. Gifford, D., Miller, C., & Kern, N. 2013, ApJ, 773, 116
3. Serra, A. L., Diaferio, A., Murante, G., & Borgani, S. 2011, MNRAS, 412, 800
4. Silverman B. W., 1986, Density Estimation for Statistics and Data Analysis, Chapman & Hall, London