SNR#
- class gammapy.astro.source.SNR(e_sn='1e51 erg', theta=<Quantity 0.1>, n_ISM=<Quantity 1. 1 / cm3>, m_ejecta=<<class 'astropy.constants.iau2015.IAU2015'> name='Solar mass' value=1.988409870698051e+30 uncertainty=4.468805426856864e+25 unit='kg' reference='IAU 2015 Resolution B 3 + CODATA 2018'>, t_stop=<Quantity 1000000. K>, age=None, morphology='Shell2D', spectral_index=2.1)[source]#
Bases:
object
Simple supernova remnant (SNR) evolution model.
The model is based on the Sedov-Taylor solution for strong explosions.
Reference: https://ui.adsabs.harvard.edu/abs/1950RSPSA.201..159T
- Parameters
Attributes Summary
Characteristic time scale when the Sedov-Taylor phase of the SNR's evolution begins.
Characteristic time scale when the Sedov-Taylor phase of the SNR's evolution ends.
Methods Summary
luminosity_tev
(t[, energy_min])Gamma-ray luminosity above
energy_min
at aget
.radius
(t)Outer shell radius at age t.
radius_inner
(t[, fraction])Inner radius at age t of the SNR shell.
Attributes Documentation
- sedov_taylor_begin#
Characteristic time scale when the Sedov-Taylor phase of the SNR’s evolution begins.
The beginning of the Sedov-Taylor phase of the SNR is defined by the condition, that the swept up mass of the surrounding medium equals the mass of the ejected mass.
The time scale is given by:
\[t_{begin} \approx 200 \left(\frac{E_{SN}}{10^{51}erg}\right)^{-1/2} \left(\frac{M_{ej}}{M_{\odot}}\right)^{5/6} \left(\frac{\rho_{ISM}}{10^{-24}g/cm^3}\right)^{-1/3} \text{yr}\]
- sedov_taylor_end#
Characteristic time scale when the Sedov-Taylor phase of the SNR’s evolution ends.
The end of the Sedov-Taylor phase of the SNR is defined by the condition, that the temperature at the shock drops below T = 10^6 K.
The time scale is given by:
\[t_{end} \approx 43000 \left(\frac{m}{1.66\cdot 10^{-24}g}\right)^{5/6} \left(\frac{E_{SN}}{10^{51}erg}\right)^{1/3} \left(\frac{\rho_{ISM}}{1.66\cdot 10^{-24}g/cm^3}\right)^{-1/3} \text{yr}\]
Methods Documentation
- luminosity_tev(t, energy_min='1 TeV')[source]#
Gamma-ray luminosity above
energy_min
at aget
.The luminosity is assumed constant in a given age interval and zero before and after. The assumed spectral index is 2.1.
The gamma-ray luminosity above 1 TeV is given by:
\[L_{\gamma}(\geq 1TeV) \approx 10^{34} \theta \left(\frac{E_{SN}}{10^{51} erg}\right) \left(\frac{\rho_{ISM}}{1.66\cdot 10^{-24} g/cm^{3}} \right) \text{ s}^{-1}\]Reference: https://ui.adsabs.harvard.edu/abs/1994A%26A…287..959D (Formula (7)).
- radius(t)[source]#
Outer shell radius at age t.
The radius during the free expansion phase is given by:
\[r_{SNR}(t) \approx 0.01 \left(\frac{E_{SN}}{10^{51}erg}\right)^{1/2} \left(\frac{M_{ej}}{M_{\odot}}\right)^{-1/2} t \text{ pc}\]The radius during the Sedov-Taylor phase evolves like:
\[r_{SNR}(t) \approx \left(\frac{E_{SN}}{\rho_{ISM}}\right)^{1/5}t^{2/5}\]- Parameters
- t
Quantity
Time after birth of the SNR
- t