SNRTrueloveMcKee

class gammapy.astro.source.SNRTrueloveMcKee(*args, **kwargs)

Bases: gammapy.astro.source.SNR

SNR model according to Truelove & McKee (1999).

Reference: http://adsabs.harvard.edu/abs/1999ApJS..120..299T

Attributes Summary

sedov_taylor_begin

Characteristic time scale when the Sedov-Taylor phase starts.

Methods Summary

radius([t])	Outer shell radius at age t.
radius_reverse_shock(t)	Reverse shock radius at age t.

Attributes Documentation

sedov_taylor_begin

Characteristic time scale when the Sedov-Taylor phase starts.

Given by \(t_{ST} \approx 0.52 t_{ch}\).

Methods Documentation

radius(t=None)

Outer shell radius at age t.

Parameters:

t : Quantity

Time after birth of the SNR.

Notes

The radius during the free expansion phase is given by:

\[R_{SNR}(t) = 1.12R_{ch}\left(\frac{t}{t_{ch}}\right)^{2/3}\]

The radius during the Sedov-Taylor phase evolves like:

\[R_{SNR}(t) = \left[R_{SNR, ST}^{5/2} + \left(2.026\frac{E_{SN}} {\rho_{ISM}}\right)^{1/2}(t - t_{ST})\right]^{2/5}\]

Using the characteristic dimensions:

\[R_{ch} = M_{ej}^{1/3}\rho_{ISM}^{-1/3} \ \ \textnormal{and} \ \ t_{ch} = E_{SN}^{-1/2}M_{ej}^{5/6}\rho_{ISM}^{-1/3}\]

radius_reverse_shock(t)

Reverse shock radius at age t.

Parameters:

t : Quantity

Time after birth of the SNR.

Notes

Initially the reverse shock co-evolves with the radius of the SNR:

\[R_{RS}(t) = \frac{1}{1.19}r_{SNR}(t)\]

After a time \(t_{core} \simeq 0.25t_{ch}\) the reverse shock reaches the core and then propagates as:

\[R_{RS}(t) = \left[1.49 - 0.16 \frac{t - t_{core}}{t_{ch}} - 0.46 \ln \left(\frac{t}{t_{core}}\right)\right]\frac{R_{ch}}{t_{ch}}t\]