Pulsar¶

class gammapy.astro.source.Pulsar(P_0='0.1 s', B='1e10 G', n=3, I=<Quantity 1.e+45 cm2 g>, R=<Quantity 1000000. cm>, age=None, L_0=None)[source]¶

Bases: object

Magnetic dipole spin-down pulsar model.

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

Parameters

P_0float: Period at birth
BQuantity: Magnetic field strength at the poles (Gauss)
nfloat: Spin-down braking index
Ifloat: Moment of inertia
Rfloat: Radius

Methods Summary

`energy_integrated`(self, t)	Total energy released by a given time.
`luminosity_spindown`(self, t)	Spin down luminosity.
`magnetic_field`(self, t)	Magnetic field at polar cap (assumed constant).
`period`(self, t)	Rotation period.
`period_dot`(self, t)	Period derivative at age t.
`tau`(self, t)	Characteristic age at real age t.

Methods Documentation

energy_integrated(self, t)[source]¶

Total energy released by a given time.

Time-integrated spin-down luminosity since birth.

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

Parameters

tQuantity: Time after birth of the pulsar.

luminosity_spindown(self, t)[source]¶

Spin down luminosity.

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

Parameters

tQuantity: Time after birth of the pulsar

magnetic_field(self, t)[source]¶

Magnetic field at polar cap (assumed constant).

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

Parameters

tQuantity: Time after birth of the pulsar.

period(self, t)[source]¶

Rotation period.

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

Parameters

tQuantity: Time after birth of the pulsar

period_dot(self, t)[source]¶

Period derivative at age t.

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

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

Parameters

tQuantity: Time after birth of the pulsar.

tau(self, t)[source]¶

Characteristic age at real age t.

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

Parameters

tQuantity: Time after birth of the pulsar.