Final answer:
High frequency bursts of activity that last for one second are called short-duration bursts. These bursts can last from a fraction of a second to a few minutes and are believed to be mergers of stellar corpses.
Step-by-step explanation:
High frequency bursts of activity that last for one second could be described as short-duration bursts. Gamma-ray bursts, which come from very distant objects, can last from a fraction of a second to a few minutes.
Short-duration bursts typically last less than 2 seconds, but can also be as short as milliseconds. They are believed to be mergers of stellar corpses, such as neutron stars or black holes.