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 ≈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.