According to the provided data, what is the approximate minimum age a dead galaxy has been observed to possess post-Big Bang?

Answer

~800 million years

Data emerging from deep-field surveys indicate that dead galaxies have been observed as old as approximately 800 million years after the Big Bang.

According to the provided data, what is the approximate minimum age a dead galaxy has been observed to possess post-Big Bang?
Spacegalaxiesastronomycosmologydead galaxies