Spectroscopic confirmation of a gravitationally lensed Lyman break
  galaxy at z$_{[CII]}$ = 6.827 using NOEMA
  We present the spectroscopic confirmation of the brightest known
gravitationally lensed Lyman break galaxy in the Epoch of Reionisation,
A1703-zD1, through the detection of [C II] at a redshift of z = 6.8269 +/-
0.0004. This source was selected behind the strong lensing cluster Abell 1703,
with an intrinsic L$_{UV}$ ~ L$^*$$_{z=7}$ luminosity and a very blue
Spitzer/IRAC [3.6]-[4.5] colour, implying high equivalent width line emission
of [O III]+H$\beta$. [C II] is reliably detected at 6.1$\sigma$ co-spatial with
the rest-frame UV counterpart, showing similar spatial extent. Correcting for
the lensing magnification, the [C II] luminosity in A1703-zD1 is broadly
consistent with the local L$_{[CII]}$ - SFR relation. We find a clear velocity
gradient of 103 +/- 22 km/s across the source which possibly indicates rotation
or an ongoing merger. We furthermore present spectral scans with no detected [C
II] above 4.6$\sigma$ in two unlensed Lyman break galaxies in the EGS-CANDELS
field at z ~ 6.6 - 6.9. This is the first time that NOEMA has been successfully
used to observe [C II] in a 'normal' star-forming galaxy at z > 6, and our
results demonstrate its capability to complement ALMA in confirming galaxies in
the Epoch of Reionisation.
