Pulsar¶

class gammapy.astro.source.Pulsar(P_0=<Quantity 0.1 s>, logB=10, n=3, I=<Quantity 1.e+45 cm2 g>, R=<Quantity 1000000. cm>, age=None, L_0=None, morphology='Delta2D')[source]¶

Bases: gammapy.astro.source.SimplePulsar

Magnetic dipole spin-down pulsar model.

Reference: http://www.cv.nrao.edu/course/astr534/Pulsars.html

Parameters:	P_0 : float Period at birth logB : float Logarithm of the magnetic field, which is constant n : float Spin-down braking index I : float Moment of inertia R : float Radius

Methods Summary

`energy_integrated`([t])	Total released energy at age t.
`luminosity_spindown`([t])	Spin down luminosity at age t.
`luminosity_tev`([t, fraction])	Gamma-ray luminosity assumed to be a certain fraction of the spin-down luminosity.
`magnetic_field`([t])	Magnetic field strength at the polar cap.
`period`([t])	Period at age t.
`period_dot`([t])	Period derivative at age t.
`tau`([t])	Characteristic age at real age t.

Methods Documentation

energy_integrated(t=None)[source]¶

Total released energy at age t.

Time-integrated spin-down luminosity since birth.

Parameters:	t : `Quantity` Time after birth of the pulsar.

Notes

The time integrated energy is given by:

\[E(t) = \dot{L}_0 \tau_0 \frac{t}{t + \tau_0}\]

luminosity_spindown(t=None)[source]¶

Spin down luminosity at age t.

Parameters:	t : `Quantity` Time after birth of the pulsar.

Notes

The spin-down luminosity is given by:

\[\dot{L}(t) = \dot{L}_0 \left(1 + \frac{t}{\tau_0}\right)^{\frac{n + 1}{n - 1}}\]

luminosity_tev(t=None, fraction=0.1)[source]¶

Gamma-ray luminosity assumed to be a certain fraction of the spin-down luminosity.

Parameters:	t : `Quantity` Time after birth of the pulsar.

magnetic_field(t=None)[source]¶

Magnetic field strength at the polar cap. Assumed to be constant.

Notes

The magnetic field is given by:

\[B = 3.2\cdot 10^{19} (P\dot{P})^{1/2} [\textnormal(Gauss)]\]

period(t=None)[source]¶

Period at age t.

Parameters:	t : `Quantity` Time after birth of the pulsar.

Notes

The period is given by:

\[P(t) = P_0\left(1 + \frac{t}{\tau_0}\right)^{\frac{1}{n - 1}}\]

period_dot(t=None)[source]¶

Period derivative at age t.

P_dot for a given period and magnetic field B, assuming a dipole spin-down.

Parameters:	t : `Quantity` Time after birth of the pulsar.

Notes

The period derivative is given by:

\[\dot{P}(t) = \frac{B^2}{3.2 \cdot 10^{19} P(t)}\]

tau(t=None)[source]¶

Characteristic age at real age t.

Parameters:	t : `Quantity` Time after birth of the pulsar.

Notes

The characteristic age is given by:

\[\tau = \frac{P}{2\dot{P}}\]