Active Galactic Nuclei (AGN)¶

This section describes how to simulate the spectra of active galactic nuclei (AGN) using the spec1d module in GEHONG.

AGN spectra are composed of multiple components, which can be generated individually or combined into a full AGN model.

Emission Line Template¶

The narrow-line region (NLR) template is initialized using the EmissionLineTemplate class with model='nlr'.

Usage Example:

from gehong import spec1d
nlr_temp = spec1d.EmissionLineTemplate(config, model='nlr')

Simulates the AGN featureless continuum as a power law.

Input Parameters:

Usage Example:

pl = spec1d.AGN_Powerlaw(config, m5100=17, alpha=-1.5, vel=10000, ebv=0.1)

Simulates the narrow emission lines in AGN spectra.

Input Parameters:

halpha: Hα narrow-line flux (\(10^{-17}\ \mathrm{erg\ s^{-1}\ cm^{-2}\ Å^{-1}}\))
logz: Gas-phase metallicity [Z/H] (dex)
vel: Line-of-sight velocity (km/s)
vdisp: Velocity dispersion (km/s)
ebv: Dust extinction E(B-V)

Usage Example:

nlr = spec1d.AGN_NLR(config, nlr_temp, halpha=300, logz=0,
                     vel=10000, vdisp=300, ebv=0.1)

Simulates the broad Hβ emission from the BLR.

Input Parameters:

Usage Example:

blr = spec1d.AGN_BLR(config, hbeta_flux=150, hbeta_fwhm=4000,
                     vel=10000, ebv=0.1)

Simulates the blended Fe II emission near Hβ.

Input Parameters:

Usage Example:

fe = spec1d.AGN_FeII(config, hbeta_broad=150, r4570=0.5,
                     vel=10000, ebv=0.1)

Each component produces a spectrum on the same wavelength grid, and they can be added to form the full AGN model.

Example:

flux = pl.flux + nlr.flux + blr.flux + fe.flux

component.wave: Wavelength array (Å)
component.flux: Flux array in units of \(10^{-17}\ \mathrm{erg\ s^{-1}\ cm^{-2}\ Å^{-1}}\)

Note

All AGN components share the same wavelength grid defined by config.