East Coast of the United States (for the first pulsar discovered)

The first pulsar discovered, PSR B1919+21, is located in the constellation Vulpecula, not along the East Coast of the United States. However, the term may refer to the overall region where early radio astronomy observatories, such as the Jodrell Bank Observatory in England or the Arecibo Observatory in Puerto Rico (which is Caribbean but sometimes included culturally), contributed to pulsar discoveries. If you mean the initial discovery location, it was made using radio telescopes in the United States, notably the Arecibo Observatory, which played a key role in studying pulsars. Pulsars are highly magnetized, rotating neutron stars emitting regular beams of radio waves.