AGN Unified Model: Torus Obscuration & Jet Beaming (2D)

Observer

You would classify this AGN as

Seyfert 1 (unobscured)

Direct view of the disk and broad-line region.

Viewing angle θ (from jet axis) 18°

Torus & Jet Parameters

Torus half-opening angle θ_o 45°

Jet bulk Lorentz factor γ 8.0

Eddington ratio (disk luminosity) 0.30

Live Readouts

Viewing angle θ

18.0°

Column density N_H

2×10²⁰

Doppler factor δ

1.00

Flux boost (δ³·⁷)

1×

How it works

The AGN unified model says every active galactic nucleus is the same object — a supermassive black hole with an accretion disk, a broad-line region (BLR) close in, a dusty obscuring torus further out, and (in radio-loud sources) a pair of relativistic jets along the spin axis. What we call it depends only on the angle θ between our line of sight and that axis:

θ < θ_o  (torus doesn't block the core)  → Type 1 (Seyfert 1 / Quasar): broad + narrow lines
θ ≥ θ_o  (torus blocks the BLR)          → Type 2 (Seyfert 2 / Radio Galaxy): narrow lines only, N_H high

If the source is radio-loud and a jet happens to point within a few degrees of us, relativistic beaming dominates everything else and we call it a blazar. Beaming strength is the Doppler factor:

δ = 1 / [γ(1 − β·cosθ)],   β = √(1 − 1/γ²)
F_observed / F_rest = δ^(3+α)   (continuous jet, spectral index α ≈ 0.7)

Small θ and large γ make δ ≫ 1 → enormous apparent brightness for the approaching jet, while the receding counter-jet (angle 180°−θ) gets deboosted toward invisibility — exactly why blazar jets look one-sided.

Viewing angle slider — this side-on cross-section fixes the jet axis vertical; dragging θ sweeps a line-of-sight ray from the core outward and shows live whether it clears the polar funnel or gets swallowed by the dusty torus.
Torus opening angle — a wider torus (bigger θ_o) means more sightlines see an unobscured Type 1 nucleus.
Lorentz factor γ & jets — raise γ and drag θ toward 0° to watch the Doppler factor and flux boost spike, and the far jet fade.
Eddington ratio — sets disk luminosity; a high-Eddington unobscured source reads as a quasar rather than a modest Seyfert 1.

Real observational evidence: the M87 and Sgr A* Event Horizon Telescope images, the Seyfert 1/2 dichotomy explained by torus inclination (Antonucci & Miller 1985 polarized broad lines in a Type 2), and blazar flares (Mrk 421, 3C 279) showing apparent faster-than-light jet-knot motion — a direct signature of δ ≫ 1.

Drag θ · this is a fixed side-on cross-section

Accretion disk / BLR Dusty torus Narrow-line ionization cones Relativistic jets