Gunn-Peterson Trough · z ≈ 6
unseel.com · neutral H scatters Lyman-α
σα 4.5×10⁻¹⁸ cm²
τGP 0
operation
Quasar UV photons
Neutral hydrogen
Lyman-α resonance
Spectrum / trough
Unseel.com · Gunn-Peterson Trough