Question: What nationality is the scientist who along with Antony Hewish discovered PSR B1919+21 ?

<P0-S0> PSR B1919+21 is a pulsar with a period of 1.3373 seconds and a pulse width of 0.04 seconds. <P0-S1>  Discovered by Jocelyn Bell Burnell and Antony Hewish on November 28, 1967, it is the first discovered radio pulsar. <P0-S2>  The power and regularity of the signals were briefly thought to resemble an extraterrestrial beacon, leading the source to be nicknamed LGM-1 (for "little green men"). <SEP> <P1-S0> PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. <P1-S1>  The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the coordinates are for the 1950.0 epoch. <P1-S2>  PSR B1937+21 was discovered in 1982 by Don Backer, Shri Kulkarni, Carl Heiles, Michael Davis, and Miller Goss. <SEP> <P2-S0>  As a postgraduate student, she discovered the first radio pulsars while studying and advised by her thesis supervisor Antony Hewish, for which Hewish shared the Nobel Prize in Physics with astronomer Martin Ryle. <P2-S1>  Bell Burnell was excluded, despite having been the first to observe and precisely analyse the pulsars. <P2-S2>  Bell Burnell was President of the Royal Astronomical Society from 2002 to 2004, president of the Institute of Physics from October 2008 until October 2010, and was interim president following the death of her successor, Marshall Stoneham, in early 2011. <P2-S3>  She was succeeded in October 2011 by Sir Peter Knight. <P2-S4>  Bell Burnell was elected as President of the Royal Society of Edinburgh in October 2014. <P2-S5>  In March 2013 she was elected Pro-Chancellor of the University of Dublin. <P2-S6> Dame Susan Jocelyn Bell Burnell, (born 15 July 1943) is a Northern Irish astrophysicist. <SEP> <P3-S0> PSR J1311–3430 is a pulsar with a spin period of 2.5 milliseconds. <P3-S1>  It is the first millisecond pulsar found via gamma-ray pulsations. <P3-S2>  The source was originally identified by the Energetic Gamma Ray Experiment Telescope as a bright gamma ray source, but was not recognized as a pulsar until observations with the Fermi Gamma-ray Space Telescope discovered pulsed gamma ray emission. <P3-S3>  The pulsar has a helium-dominated companion much less massive than itself, and the two are in an orbit with a period of 93.8 minutes. <P3-S4>  The system is explained by a model where mass from the low mass companion was transferred on to the pulsar, increasing the mass of the pulsar and decreasing its period. <P3-S5>  These systems are known as Black Widow Pulsars, named after the original such system discovered, PSR B1957+20, and may eventually lead to the companion being completely vaporized. <P3-S6>  Among systems like these, the orbital period of PSR J1311–3430 is the shortest ever found. <P3-S7>  Spectroscopic observations of the companion suggest that the mass of the pulsar is 2.7 formula_1 (solar masses). <P3-S8>  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.