causticsnupy 1.0.4

Python package for determining cluster members using caustic technique.

CausticSNUpy

Python implementation of the caustic technique for identifying galaxy cluster membership and measuring the mass profile of the cluster. Original technique is 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

Installatation is available through pip or direct install from the githup repo.

Method 1: installing from pip repository

1. On your terminal, type and enter pip install causticsnupy.

pip install CausticSNUpy

Method 2: installing from zip file

1. Download the .zip file from github repository. Click 'Code' button on the top right of the page, and click 'Download ZIP'.
2. In your terminal, change directory to the location where the .zip file is.
3. Type and enter the following:

pip install CausticSNUpy-main.zip

Method 3: run setup.py

1. Clone the repository to your local machine.
2. Open terminal and change directory to where setup.py is located.
3. In your terminal, type and run

python setup.py install

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