xseqtherm

Context: models

Synopsis

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

http://www.astro.yale.edu/coppi/eqpair/eqpap4.ps .

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. 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., 'xset EQTHERM_PRECISION 0.05' (see 'ahelp set_xsxset').

This is an additive model component.

xseqtherm 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 12.7.1 of the XSpec models is supplied with CIAO 4.4.1.

Bugs

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