On-the-Fly Mapping of New Pulsars

Abstract

Current single dish, low-frequency radio pulsar surveys provide efficient sky coverage, but poor localization of new discoveries. Here, we describe a practical technique for rapidly localizing pulsars discovered in these surveys with on-the-fly mapping and provide code to facilitate and formalize its implementation. As a proof of concept, we alter the positions of four test sources and use the Green Bank Telescope (GBT) 350 MHz receiver to recover source positions within $\approx$1$-$3' of their true values, compared to an 18' error radius for new discoveries. Achieving similar precision with a traditional gridding strategy using the GBT requires 2$-$3 times as much telescope time (including overhead), multiple receivers and relies on assumptions about the pulsars' spectral indices. For one of our test sources (PSR J1400$-$1431), this method revealed a discrepancy with the initial, published position, prompting additional follow-up and an improved timing solution. Rapid localization is important for improving data quality and providing flexibility in choice of center frequency for future timing observations - both of which facilitate evaluating new millisecond pulsars for potential inclusion in pulsar timing arrays.