README.md

Disclaimer [This has not been mantained for a while, please review the code before using for your research.]

QSOSED

This Python module handles various calculations involving the accretion physics of AGNs. In particular, it implements the qsosed model of Xspec, explained in Kubota & Done (2018) to create the flux energy distribution in the UV/X-Ray band of an AGN.

the SED model has three characteristic regions: the outer standard disc region; the warm Comptonising region; and the inner hot Comptonising region.

For the warm Comptonising region, this model adopts the passive disc scenario tested by Petrucci et al. 2018 (https://ui.adsabs.harvard.edu//#abs/2018A&A...611A..59P/abstract). Here, the flow is assumed to be completely radially stratified, emitting as a standard disc blackbody from Rout to Rwarm, as warm Comptonisation from Rwarm to Rhot and then makes a transition to the hard X-ray emitting hot Comptonisation component from Rhot to RISCO. The warm Comptonisation component is optically thick, so is associated with material in the disc. Nonetheless, the energy does not thermalise to even a modified blackbody, perhaps indicating that significant dissipation takes place within the vertical structure of the disc, rather than being predominantly released in the midplane.

At a radius below Rhot, the energy is emitted in the hot Comptonisation component. This has much lower optical depth, so it is not the disc itself. In the model, the albedo is fixed at a = 0.3, and the seed photon temperature for the hot Comptonisation component is calculated internally. In contrast to optxagnf, this model does not take the color temperature correction into account.

Table of contents

• PyAGN
• Table of contents
  • Setup
  • Requirements
  • Parameters for the SED class
  • Example usage
  • Comparison with Xspec

Setup

The easiest install method is

pip install pyagn

Requirements

Requirements are installed automatically if the package is installed via pip, otherwise they can also be install through

pip install -r requirements.txt

The specific requirements are:

numpy
scipy
matplotlib
astropy

Parameters for the SED class

parameter	type	description	default
M	float	Black Hole mass in solar masses.	1e8
mdot	float	Black Hole accretion rate in Eddington units.	0.5
astar	float	Black Hole dimensionless spin absolute value.	0
astar_sign	int	+1 for prograde rotation, -1 for retrograde.	+1
reprocessing	boolean	True to include reprocessing, False otherwise.	True
hard_xray_fraction	float	Dissipated corona luminosity in Eddington units.	0.02
corona_electron_energy	float	Electron temperature for the hot Comptonisation component in keV	100
warm_electron_energy	float	Electron temperature for the warm Comptonisation component in keV.	0.2
warm_photon_index	float	The spectral index $\Gamma$ of the warm Comptonisation component.	2.5
reflection_albedo	float	reflection albedo for the reprocessed flux	0.3

Example usage

from pyagn import SED
from astropy import units as u

# initialize class
M = 1e8
mdot = 0.5
a = 0
sed_test = SED(M=M, mdot = mdot, astar = 0)

# choose a distance in cm.
distance = 100 * u.Mpc
distance_cm = distance.to(u.cm).value

# compute total flux
total_flux = sed_test.total_flux( distance = distance_cm)

# we can also easily plot the results

fig, ax = plt.subplots(9,6)
sed_test.plot_total_flux(distance, ax=ax)

Comparison with Xspec

We can test that our Python implementation gives the same results as the Xspec code. Note that in order to recreate Xspec results, the innner disk radius has to be multiplied by a factor of 0.85. This is an artifact of the energy binning in Xspec.

M = 1e8
mdot = 0.5