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            bkn2pow: broken power law, 2 break energies

A three-segment broken power law (ie with two break energies).

E Ebreak,1

Ebreak,1 ≤ E ≤ Ebreak,2

Ebreak,2 ≤ E

where :

par1=

power law photon index for E < Ebreak,1

par2=Ebreak,1

first break point for the energy, keV

par3=

power law photon index for Ebreak,1 < E < Ebreak,2

par4=Ebreak,2

second break point for the energy, keV

par5=

power law photon index for E > Ebreak,2

Norm =K

photons keV-1cm-2s-1 at 1 keV

 

If POW_EMIN and POW_EMAX have been defined by the xset command then the norm becomes the flux in units of 10-12 ergs cm-2 s-1 over the energy range (POW_EMIN, POW_EMAX) keV unless POW_EMIN = POW_EMAX in which case the norm becomes the flux density in micro-Jansky at POW_EMIN keV. In these cases it is important that POW_EMIN and POW_EMAX lie within the energy range on which the model is being evaluated.

 

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