Note
Go to the end to download the full example code or to run this example in your browser via Binder
Power law 2 spectral model#
This model parametrises a power law spectrum with integral as amplitude parameter.
It is defined by the following equation:
\[\phi(E) = F_0 \cdot \frac{\Gamma + 1}{E_{0, max}^{-\Gamma + 1}
- E_{0, min}^{-\Gamma + 1}} \cdot E^{-\Gamma}\]
See also: https://fermi.gsfc.nasa.gov/ssc/data/analysis/scitools/source_models.html
Example plot#
Here is an example plot of the model:
from astropy import units as u
import matplotlib.pyplot as plt
from gammapy.modeling.models import Models, PowerLaw2SpectralModel, SkyModel
energy_bounds = [0.1, 100] * u.TeV
model = PowerLaw2SpectralModel(
amplitude=u.Quantity(1e-12, "cm-2 s-1"),
index=2.3,
emin=1 * u.TeV,
emax=10 * u.TeV,
)
model.plot(energy_bounds)
plt.grid(which="both")
![plot powerlaw2](../../../_images/sphx_glr_plot_powerlaw2_001.png)
YAML representation#
Here is an example YAML file using the model:
components:
- name: power-law2-model
type: SkyModel
spectral:
type: PowerLaw2SpectralModel
parameters:
- name: amplitude
value: 1.0e-12
unit: cm-2 s-1
- name: index
value: 2.3
- name: emin
value: 1.0
unit: TeV
- name: emax
value: 10.0
unit: TeV
metadata:
creator: Gammapy 1.2
date: '2024-02-29T10:21:56.440031'
origin: null