Discovery of the millisecond pulsar PSR J2043+1711 in a Fermi source with the Nancay Radio Telescope

We report the discovery of the millisecond pulsarPSR J2043+1711 in a search of a Fermi Large Area Telescope (LAT) source with no known associations, with the Nancay Radio Telescope. The new pulsar, confirmed with the Green Bank Telescope, has a spin period of 2.38 ms, is relatively nearby (d <~ 2 kpc), and is in a 1.48 day orbit around a low mass companion, probably a He-type white dwarf. Pulsed gamma-ray emission was detected in the data recorded by the Fermi LAT. The gamma-ray light curve and spectral properties are typical of other gamma-ray millisecond pulsarsseen with Fermi. X-ray observations of the pulsarwith Suzaku and the Swift/XRT yielded no detection. At 1.4 GHz we observe strong flux density variations because of interstellar diffractive scintillation, however a sharp peak can be observed at this frequency during bright scintillation states. At 327 MHz the pulsaris detected with a much higher signal-to-noise ratio and its flux density is far more steady. However, at that frequency the Arecibo instrumentation cannot yet fully resolve the pulse profile. Despite that, our pulse time-of- arrivalmeasurements have a post-fit residual rms of 2 \mus. This and the expected stability of this system has made PSR J2043+1711 one of the first new Fermi-selected millisecond pulsarsto be added to pulsargravitational wave timing arrays. It has also allowed a significant measurement of relativistic delays in the timesof arrivalof the pulses due to the curvature of space-time near the companion, but not yet with enough precision to derive useful masses for the pulsarand the companion. A mass for the pulsarbetween 1.7 and 2.0 solar massescan be derived if a standard millisecond pulsarformation model is assumed. In this article we also present a comprehensive summary of pulsarsearches in Fermi LAT sources with the Nancay Radio Telescopeto date.