A pulsar is known for what characteristic?

A pulsar is primarily recognized for its characteristic of emitting flashes of electromagnetic emissions, often in the form of radio waves. This occurs due to the rapid rotation of the pulsar, which is a highly magnetized, rotating neutron star. As the pulsar spins, it emits beams of radiation from its magnetic poles. If these beams sweep across the Earth, they can be detected as pulses of radiation, leading to the phenomenon observed as flashing signals.

While they do emit light as a star and produce radio waves, the key defining feature of a pulsar is its periodicity and the fact that these emissions can cover various parts of the electromagnetic spectrum. This includes not just radio waves but also X-rays and gamma rays, making "flashes of electromagnetic emissions" a more accurate and comprehensive descriptor of a pulsar's characteristic behavior.

The other options, while somewhat related, do not encompass the full breadth of what defines a pulsar, particularly the iconic flashing nature that characterizes their detection.