  We study the Coulomb dissociation of the 19C nucleus in an effective field
theory that uses the 18C core and the neutron as effective degrees of freedom
and exploits the separation of scales in this halo system. We extract the
effective-range parameters and the separation energy of the halo neutron from
the experimental data taken at RIKEN by Nakamura et al. We obtain a value of
(575 +/- 55(stat.) +/- 20(EFT)) keV for the one-neutron separation energy of
19C, and (7.75 +/- 0.35(stat.) +/- 0.3(EFT)) fm for the 18C-neutron scattering
length. The width of the longitudinal momentum distribution predicted by EFT
using this separation energy agrees well with the experimental data taken at
NSCL by Bazin et al., reaffirming the dominance of the s-wave configuration of
the valence neutron.
