Question: What nationality is the scientist who along with Antony Hewish discovered PSR B1919+21 ?
Sentence (from "PSR J1311–3430"): Though there is considerable uncertainty in this estimate, the minimum mass for the pulsar that the authors find adequately fits the data is 2.15 formula_1, which is still more massive than PSR J1614–2230, the previous record holder for most massive known pulsar.
Relevant evidence: No