PyFRS

This python code is dedicated to compute the multi-band synchrotron emissions from the Forward-Reverse Shocks of a GRB or TDE jet.

Features

fs.py computes synchrotron emission from the forward shock of a jet/outflow. It includes:

• Synchrotron emission from relativistic jet or non-relativistic outflow;
• Jet/outflow dynamics cover Coasting, deceleration and Newtonian phases;
• Arbitrary medium density profile;
• Arbitrary viewing angles (on and off-axis);
• Self-absorbtion, SSC and EIC;
• Jet break effect;
• Energy injection;
• Density jump.

rs.py computes synchrotron emission from the reverse shock of a jet/outflow.

Future:

• Neutrino emission

Installing

Clone the repository:

git clone https://github.com/leiwh/PyFRS

Or install with pip:

pip install PyFRS

It runs properly with anaconda and VS Code.

Usage

The forward and reverse shock modules can be used separately.

Forward Shock (FS)

For forward shock (FS), import the library with import fs in your python code.

The main function of interest isfs.FS_flux(t, nu, **Z). See LightCurve.ipynb for a simple example.

1. t: a 1-D array of observer-frame times, in seconds (s)

2. nu: a 1-D array, the same shape as t, of observer-frame frequencies, in Hertz (Hz)

3. Fnu=fs.FS_flux(t, nu, **Z) is an array, same size as t and nu, the model flux in mJy at each time and frequency.

4. For forward shock afterglows Z has 12 required keyword arguments:

• z Redshift
• k Medium density profile index
• SSC SSC
• XIC EIC
• E0 Isotropic-equivalent energy in erg
• Gamma0 Initial bulk Lorentz factor
• theta_j Jet opening angle
• theta_obs Viewing angle in deg
• n18 CNM density at 10^18cm
• p Electron energy distribution index
• epsilon_e Fraction of the shock energy into electrons
• epsilon_B Fraction of the shock energy in magnetic field

Reverse Shock (RS)

For reverse shock (RS), import the library with import rs in your python code.

The main function of interest isrs.RS_flux(t, nu, **Z). See LightCurve.ipynb for a simple example.

1. t: a 1-D array of observer-frame times, in seconds (s)

2. nu: a 1-D array, the same shape as t, of observer-frame frequencies, in Hertz (Hz)

3. Fnu=rs.RS_flux(t, nu, **Z) is an array, same size as t and nu, the model flux in mJy at each time and frequency.

4. For reverse shock afterglows Z has 12 required keyword arguments:

• z Redshift
• k Medium density profile index
• SSC SSC
• XIC EIC
• E0 Isotropic-equivalent energy in erg
• Gamma0 Initial bulk Lorentz factor
• theta_j Jet opening angle
• theta_obs Viewing angle in deg
• n18 CNM density at 10^18cm
• p Electron energy distribution index
• epsilon_e Fraction of the shock energy into electrons
• epsilon_B Fraction of the shock energy in magnetic field

References

Zhang, B. 2018, The Physics of Gamma-Ray Bursts

Gao, H., Lei, W.-H., Zou, Y.-C., Wu, X.-F., & Zhang, B. 2013, NewAR, 57, 141

Lei, W.-H., Yuan, Q., Zhang, B., & Wang, D. 2016, ApJ, 816, 20

Zhu, Z.-P., Xu, D., Fynbo, J. P. U., et al. 2023, ApJ, 948, 30