"Jl Han, Et Al., Raa 2021 Vol. 21 No. 5, 107: The Fast Galactic Plane Pulsar Snapshot Survey: I. Project Design And Pulsar Discoveries"

The newly commissioned Chinese radio telescope known as FAST is the most sensitive radio telescope in the world. The name FAST derives from its full title “Fivehundred-meter Aperture Spherical Telescope” giving a clue to why it is so sensitive. Even before the recent demise of the Arecibo radio telescope in Puerto Rico, it had the largest collecting area of any “single-dish” radio telescope. Its 300-m effective diameter, combined with a very sensitive 19-beam receiver operating in the “Lband” around 1.4 GHz, makes it more than an order of magnitude more sensitive than any other existing radio telescope operating in this band. Discovery of previously unknown pulsars is one of the most exciting applications of this high sensitivity. Pulsars are relatively weak radio sources that are characterized by their highly periodic pulsed emission. They have pulse periods of between about 1.4 milliseconds and 23 seconds and are often found in short-period binary orbits about another star. Pulsar timing observations over decade intervals have shown that the long-term stability of the pulse period, especially for the short-period pulsars known as “millisecond pulsars” (MSPs), rivals that of the best atomic frequency standards on Earth. The existence of these highly stable clocks scattered through our Galaxy, far from the perturbations of a noisy Earth, has led to many exciting applications including efforts to detect lowfrequency gravitational waves from distant galaxies and to some of the most stringent available tests of theories of gravitation. Their sharp pulses and high polarization make possible detailed studies of the interstellar medium between us and the pulsar. Finally, with their magnetic fields of billions of tesla and rapid rotation, they are highly efficient particle accelerators, generating ultra-relativistic particle streams that lead to the observed pulses through mechanisms that are still not fully understood after more than five decades of effort.