Aura of death.

You may only cast this spell if you have a use of event horizon remaining. For one minute, the area in a 30 ft radius of you suffers the effects of your event horizon feature, as well as the effects of sickening radiance. You can designate creatures to remain unaffected. This expends your event horizon, and you cannot use your event horizon until this spell wears off.

At Higher Levels

When you cast this spell at fifth level, you can concentrate for up to ten minutes, at seventh level you can concentrate for up to an hour. At 9th level it lasts until dispelled. If cast at ninth level, you cannot cast spells or cantrips for 1d12x1d6 days.