Discovery of the millisecond pulsar PSR J2043+1711 in a Fermi source
  with the Nancay Radio Telescope
  We report the discovery of the millisecond pulsar PSR 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 pulsars seen with Fermi. X-ray observations of the pulsar
with 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 pulsar is 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-arrival measurements 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 pulsars
to be added to pulsar gravitational wave timing arrays. It has also allowed a
significant measurement of relativistic delays in the times of arrival of the
pulses due to the curvature of space-time near the companion, but not yet with
enough precision to derive useful masses for the pulsar and the companion. A
mass for the pulsar between 1.7 and 2.0 solar masses can be derived if a
standard millisecond pulsar formation model is assumed. In this article we also
present a comprehensive summary of pulsar searches in Fermi LAT sources with
the Nancay Radio Telescope to date.
