Leptonic relativistic jet model.
NOTE: This model is now in the Xspec release and this page is superceded by the Xspec manual
This is the single zone, leptonic relativistic jet code of Ghisellini & Tavecchio (2009, hereafter GT09), as used in Ghisellini et al (2010), coded up by Gardner & Done (2017). Please reference all of these papers if you use this model in xspec.
The default parameters reproduce the mean FSRQ spectrum in G10 (except that our synchrotron self absorption cutoff is at a lower frequency) The spectrum longward of this cutoff is assumed to have a flat spectrum in Lv, as appropriate for the sum of self-absorbed components further down the jet.
1 = mass, black hole mass in solar masses
this is the DISC luminosity, for external Comptonisation. THIS IS SET TO ZERO for log L/LEdd < -2 as the accretion flow is assumed to make a transition to an Advection dominated state. For log L/LEdd ≥ -2 the disc luminosity is set by the black hole mass and L/LEdd so Ldisc=1.3x1038 MBH (L/LEdd). The peak temperature of the disc is set by equation 1 in GT09 i.e. black hole spin has no effect.
parameters 4-7 determine the physical parameters of the jet and its boost
4 = thetaobs, inclination angle (deg) between the jet axis and line of sight
parameters 8-14 are all in the jet frame
8 = B, Magnetic field in the jet (Gauss)
The code works on its own energy grid, from 107 Hz to 1028 Hz. It calculates the total spectrum, summing up the synchrotron emission, together with the self-Compton, EC disc, EC X-ray corona, EC BLR, EC X-ray reflection from BLR and EC torus components, using the seed photon densities assumed in GT09. These individual components can be written out individually (see e.g. Kynock et al 2017), by editing the code and uncommenting out lines which write(2,*). This produces file fort.2 in the directory where xspec is being run.
The individual seed photon densities within the jet can likewise be extracted from the code by uncommenting lines which write(3,*). Perhaps more useful is the self consistent electron distribution, Nγ, which can be written out by uncommenting out lines which write(908,*) - writing to file 908.
The code writes out to the screen the components of jet power in the observers frame:
Keith Arnaud, Lab. for High Energy Astrophysics, NASA/Goddard Space Flight Center
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