Pulsars and Fundamental Physics with the Next-Generation Very Large Array (ngVLA)

The ngVLA is a large, transformative radio telescope that will cover a wide range of radio frequencies. One of its key science goals is to find and use Galactic pulsars to study fundamental physics. Of special interest to the astrophysics community are Galactic Center (GC) pulsars, for example a pulsar closely orbiting Sag A*, enabling a suite of general relativistic tests complementing those of VLTI/GRAVITY and the Event Horizon Telescope; a possible population of GC millisecond pulsars, the absence of which would imply that dark matter is the origin of the GC gamma-ray excess; and magnetars and pulsar-black hole binary systems, both of which are rare objects and thus likely to reside very far from our Solar System. All of these pulsar types are extremely difficult to detect with current instruments because they are distant and thus highly scattered at typical pulsar observing frequencies (usually under 2-3 GHz). Because of the ngVLA’s unprecedented sensitivity, it will be able to detect pulsars at significantly higher frequencies (5 or more GHz), where they are much weaker but also experience negligible scattering even at very high distances. In addition to distant pulsars, the ngVLA will also be a valuable instrument for improved pulsar timing for the NANOGrav pulsar timing array, and will therefore play an important role in detecting and characterizing gravitational wave-emitting binary supermassive black holes.