def define_flux_crab_above_energy(emin=1 * u.TeV, emax=10 * u.TeV):
crab = CrabSpectrum('meyer').model
crabMAGIC = LogParabola(amplitude=3.23e-11 * u.Unit('cm-2 s-1 TeV-1'), reference=1 * u.TeV, alpha=2.47, beta=0.24)
crab_flux_above_1TeV = crabMAGIC.integral(emin=emin, emax=emax)
crab_flux_above_1TeV_model = crab.integral(emin=emin, emax=emax)
return crab_flux_above_1TeV, crab_flux_above_1TeV_model
def define_flux_crab_above_energy():
emin, emax = [1, 10] * u.TeV
# crab = CrabSpectrum('meyer').model
crabMAGIC = LogParabola(amplitude=3.23e-11 * u.Unit('cm-2 s-1 TeV-1'),
reference=1 * u.TeV,
alpha=2.47,
beta=-0.24)
crab_flux_above_1TeV = crabMAGIC.integral(emin=emin, emax=emax)
print(crab_flux_above_1TeV)
crab_flux_above_1TeV = crab_flux_above_1TeV.to('cm-2 s-1')
return crab_flux_above_1TeV
def flux_amplitude_from_energy_flux(alpha, beta, energy_flux):
spec = LogParabola(
amplitude=1 * u.Unit('cm-2 s-1 TeV-1'),
reference=1 * u.TeV,
alpha=alpha,
beta=-beta,
)
# Assumption before for `energy_flux` was energy band 1 to 10 TeV
emin_int = 1 * u.TeV
emax_int = 10 * u.TeV
pivot_energy = 1 * u.TeV
energy_flux_standard_candle = spec.energy_flux(emin=emin_int, emax=emax_int)
flux_at_1TeV = energy_flux / energy_flux_standard_candle * u.Unit('cm-2 s-1 TeV-1')
# print('std: ', energy_flux_standard_candle, 'energy_flux: ', energy_flux, flux_at_1TeV)
flux_at_1TeV = flux_at_1TeV.to('cm-2 s-1 MeV-1')
spec2 = LogParabola(amplitude=flux_at_1TeV, reference=pivot_energy, alpha=alpha, beta=beta)
energy_flux_above_1TeV = spec2.energy_flux(emin=emin_int, emax=10 * u.TeV)
# print('c',energy_flux_above_1TeV.to('TeV cm-2 s-1'),energy_flux_above_1TeV.to('TeV cm-2 s-1')/(flux_at_1TeV.to('cm-2 s-1 TeV-1')/)) )
flux_above_1TeV = spec2.integral(emin=emin_int, emax=10 * u.TeV)
flux_above_1TeV = flux_above_1TeV.to('cm-2 s-1')
# evaluating Crab flux at and above 1 TeV by using MAGIC Crab spectrum from JHEA 2015
crab_flux_above_1TeV, crab_flux_above_1TeV_model = define_flux_crab_above_energy(emin=1 * u.TeV, emax=10 * u.TeV)
crabMAGIC = LogParabola(amplitude=3.23e-11 * u.Unit('cm-2 s-1 TeV-1'), reference=1 * u.TeV, alpha=2.47, beta=0.24)
# plt.figure()
# min, max = [50*u.GeV,50*u.TeV]
# crabMAGIC.plot(min,max)
# crab = CrabSpectrum('meyer').model
crab_flux_above_1TeV = crab_flux_above_1TeV.to('cm-2 s-1')
crab_flux_above_1TeV_model = crab_flux_above_1TeV_model.to('cm-2 s-1')
crab_flux_at_1TeV = crabMAGIC(pivot_energy).to('MeV-1 cm-2 s-1')
# computing flux at and above 1 TeV in crab units
flux_at_1TeV_cu = (flux_at_1TeV / crab_flux_at_1TeV)*100
flux_above_1TeV_cu = (flux_above_1TeV / crab_flux_above_1TeV)*100
# print(crab_flux_above_1TeV, flux_above_1TeV, flux_above_1TeV / crab_flux_above_1TeV, flux_above_1TeV_cu )
flux_above_1TeV_cu_model = (flux_above_1TeV / crab_flux_above_1TeV_model).to('%')
return flux_at_1TeV, flux_at_1TeV_cu, flux_above_1TeV, flux_above_1TeV_cu