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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')

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)

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)

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)

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)

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)

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)

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)

Characteristic age at real age t.

Parameters:

t : Quantity

Time after birth of the pulsar.

Notes

The characteristic age is given by:

$$\tau = \frac{P}{2\dot{P}}$$