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AHELP for CIAO 4.10 Sherpa v1


Context: models


Component of Paolo Coppi's hybrid (thermal/non-thermal) hot plasma emission models.


xseqpair, xseqtherm, and xscompth models are based on Paolo Coppi's hybrid thermal/non-thermal hot plasma emission model for X-ray binaries. The underlying physics and a detailed description of the code are included in the draft paper

These models should not be used without reading and understanding this paper. Simplified models xseqtherm and xscompth are provided for cases where non-thermal processes are not important and photon-photon pair production can be ignored. These should only be used if lbb <= 10.

The temperature of the thermal component of the electron distribution and the total electron optical depth (for both ionization electrons and electron-positron pairs) are written out if the chatter level is set to 15 (using set_xschatter). This information is important for checking self-consistency.

In versions 1.10 and above, the Compton reflection is done by a call to the ireflct model code, and the relativistic blurring by a call to rdblur. This does introduce some changes in the spectrum from earlier versions. For the case of a neutral reflector (i.e. the ionization parameter is zero), more accurate opacities are calculated. For the case of an ionized reflector, the old version assumed that for the purposes of calculating opacities the input spectrum was a power-law (with index based on the 2-10 keV spectrum). The new version uses the actual input spectrum, which is usually not a power law, giving different opacities for a given ionization parameter and disk temperature. The Greens' function integration required for the Compton reflection calculation is performed to an accuracy of 0.01 (i.e. 1%). This can be changed using, e.g.

sherpa> set_xsxset('EQPAIR_PRECISION', '0.05')

This is an additive model component.

xscompth Parameters

Number Name Description
1 theta ratio of the hard to soft compactnesses
2 showbb the soft photon compactness
3 kT_bb if > 0 then temperature of the inner edge of the accretion disk for the diskbb model; if < 0 then abs(kTbb) is the Tmax parameter for the diskpn model
4 Ref0n fraction of power supplied to energetic particles which goes into accelerating non-thermal particles
5 tau_p the Thomson scattering depth
6 radius the size of the scattering region (cm)
7 g_min minimum Lorentz factor of the pairs
8 g_max maximum Lorentz factor of the pairs
9 G_inj if < 0 then non-thermal spectrum is assumed mono-energetic at gmax; if > 0 then a power-law from gmin to gmax
10 pairinj if = 0 then accelerated particles are electrons from thermal pool; if = 1 then accelerated particles are electrons and positrons
11 cosIncl inclination of reflecting material wrt line-of-sight
12 Refl fraction of scattering region's emission intercepted by reflecting material
13 Fe_abund relative abundance of iron
14 AbHe relative abundance of other metals
15 T_disk temperature of reflecting disk
16 xi ionization parameter of reflector
17 Beta power-law index with radius of disk reflection emissivity
18 Rin inner radius of reflecting material (GM/c2)
19 Rout outer radius of reflecting material (GM/c2)
20 Redshift z
norm norm Normalization

XSPEC version

This information is taken from the XSPEC User's Guide. Version 12.9.1n of the XSPEC models is supplied with CIAO 4.10.


For a list of known bugs and issues with the XSPEC models, please visit the XSPEC bugs page.

To check the X-Spec version used by Sherpa, use the get_xsversion routine from the xspec module:

sherpa> from sherpa.astro.xspec import get_xsversion
sherpa> get_xsversion()

See Also

absorptionedge, absorptiongaussian, absorptionlorentz, absorptionvoigt, accretiondisk, atten, bbody, bbodyfreq, beta1d, beta2d, blackbody, box1d, box2d, bpl1d, bremsstrahlung, brokenpowerlaw, ccm, const1d, const2d, cos, delta1d, delta2d, dered, devaucouleurs2d, disk2d, edge, emissiongaussian, emissionlorentz, emissionvoigt, erf, erfc, exp, exp10, fm, gauss1d, gauss2d, hubblereynolds, jdpileup, linebroad, list_model_components, list_models, lmc, load_xscflux, load_xsgsmooth, load_xsireflect, load_xskdblur, load_xskdblur2, load_xskerrconv, load_xslsmooth, load_xspartcov, load_xsrdblur, load_xsreflect, load_xssimpl, load_xszashift, load_xszmshift, log, log10, logabsorption, logemission, logparabola, lorentz1d, lorentz2d, models, normbeta1d, normgauss1d, normgauss2d, opticalgaussian, poisson, polynom1d, polynom2d, polynomial, powerlaw, powlaw1d, recombination, scale1d, scale2d, schechter, seaton, sersic2d, shell2d, sigmagauss2d, sin, sm, smc, sqrt, stephi1d, steplo1d, tablemodel, tan, xgal, xs, xsabsori, xsacisabs, xsagauss, xsapec, xsbapec, xsbbody, xsbbodyrad, xsbexrav, xsbexriv, xsbkn2pow, xsbknpower, xsbmc, xsbremss, xsbvapec, xsbvvapec, xsc6mekl, xsc6pmekl, xsc6pvmkl, xsc6vmekl, xscabs, xscemekl, xscevmkl, xscflow, xscompbb, xscompls, xscompmag, xscompps, xscompst, xscomptb, xscomptt, xsconstant, xsconvolve, xscplinear, xscutoffpl, xscyclabs, xsdisk, xsdiskbb, xsdiskir, xsdiskline, xsdiskm, xsdisko, xsdiskpbb, xsdiskpn, xsdust, xsedge, xseplogpar, xseqpair, xseqtherm, xsequil, xsexpabs, xsexpdec, xsexpfac, xsezdiskbb, xsgabs, xsgadem, xsgaussian, xsgnei, xsgrad, xsgrbm, xsheilin, xshighecut, xshrefl, xskerrbb, xskerrd, xskerrdisk, xslaor, xslaor2, xslogpar, xslorentz, xslyman, xsmeka, xsmekal, xsmkcflow, xsnei, xsnotch, xsnpshock, xsnsa, xsnsagrav, xsnsatmos, xsnsmax, xsnsmaxg, xsnsx, xsnteea, xsnthcomp, xsoptxagn, xsoptxagnf, xspcfabs, xspegpwrlw, xspexmon, xspexrav, xspexriv, xsphabs, xsplabs, xsplcabs, xsposm, xspowerlaw, xspshock, xspwab, xsraymond, xsredden, xsredge, xsrefsch, xsrnei, xssedov, xssirf, xssmedge, xsspexpcut, xsspline, xssrcut, xssresc, xssss_ice, xsstep, xsswind1, xstbabs, xstbgrain, xstbvarabs, xsuvred, xsvapec, xsvarabs, xsvbremss, xsvequil, xsvgadem, xsvgnei, xsvmcflow, xsvmeka, xsvmekal, xsvnei, xsvnpshock, xsvphabs, xsvpshock, xsvraymond, xsvrnei, xsvsedov, xsvvapec, xsvvgnei, xsvvnei, xsvvnpshock, xsvvpshock, xsvvrnei, xsvvsedov, xswabs, xswndabs, xsxion, xszagauss, xszbabs, xszbbody, xszbremss, xszdust, xszedge, xszgauss, xszhighect, xszigm, xszpcfabs, xszphabs, xszpowerlw, xszredden, xszsmdust, xsztbabs, xszvarabs, xszvfeabs, xszvphabs, xszwabs, xszwndabs, xszxipcf

Last modified: December 2015
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