A Sunburst Bombardment is a T'au military tactic that can be performed by orbiting T'au starships to aid friendly ground forces engaged in a difficult combat against a world's defenders.
Sunburst Bombardments are often used to aid large-scale planetary assaults during the initial planetstrike.
When the command is given, the skies over the target world flash with blinding white as the T'au launch a massive onslaught of Lumina Flares at the foe, saturating and confusing any automated defensive Auspexes or tracking stations with the light.
The shadow-haunted battlefield is illuminated starkly, each enemy stronghold now a glimmering beacon for the T'au forces' concentrated fire.
- Planetstrike (5th Edition), pg. 45