Paolo Coppi's hybrid (thermal/nonthermal) hot
plasma emission model
NOTE: This model is now in the Xspec release and this page is superceded by the Xspec manual
These three models are based on Paolo Coppi's hybrid thermal/nonthermal hot
plasma emission model for Xray binaries. The underlying physics and a
detailed description of the code are included in this draft paper. Do not use these models without
reading and understanding this paper. The original website for these
models is http://www.astro.yale.edu/coppi/eqpair.
The parameters for eqpair are
par1 = l_h/l_s, ratio of the hard to soft compactnesses
par2 = l_bb, the soft photon compactness
par3 = kT_bb, if > 0 then temperature of the inner edge of the
accretion disk for the diskbb model; if < 0 then abs(kT_bb) is the
T_max parameter for the diskpn model.
par4 = l_nt/l_h, fraction of power supplied to energetic particles
which goes into accelerating nonthermal particles.
par5 = tau_p, the Thomson scattering depth.
par6 = radius, the size of the scattering region (cm).
par7 = g_min, minimum Lorentz factor of the pairs.
par8 = g_max, maximum Lorentz factor of the pairs.
par9 = G_inj, if < 0 then nonthermal spectrum is assumed
monoenergetic at g_max; if > 0 then a powerlaw from g_min to g_max.
par10 = pairinj, if = 0 then accelerated particles are electrons from
thermal pool; if = 1 then accelerated particles are electrons and positrons.
par11 = cosIncl, inclination of reflecting material wrt lineofsight.
par12 = Refl, fraction of scattering region's emission intercepted by
reflecting material.
par13 = Fe_abund, relative abundance of iron.
par14 = Ab>He, relative abundance of other metals.
par15 = T_disk, temperature of reflecting disk.
par16 = xi, ionization parameter of reflector.
par17 = Beta, powerlaw index with radius of disk reflection emissivity.
par18 = Rin, inner radius of reflecting material (GM/c^2).
par19 = Rout, outer radius of reflecting material (GM/c^2).
par20 = redshift.
Simplified models eqtherm and compth are provided for cases where nonthermal processes
are not important and photonphoton pair production can be ignored. These should only be used if l_bb <~ 10.
The source code and required data files are included in this gzipped tar file. You will need to edit
the file xseqpair.f to ensure that DATADIR points to the correct directory.
Keith Arnaud,
Lab. for High Energy Astrophysics, NASA/Goddard Space Flight Center
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