Answer: phosphorescence

AnswerCrossword Clue
PHOSPHORESCENCEIgnis fatuus, e.g.
phosphorescenceLight emitted by a substance without combustion or perceptible heat
phosphorescenceThe emission of radiation in a similar manner to fluorescence but on a longer timescale, so that emission continues after excitation ceases
phosphorescenceluminescence that continues after the source of excitation has been removed