  Starting from chiral two-nucleon (2NF) and chiral three-nucleon (3NF)
potentials, we present a detailed study of 17Ne, a Borromean system, with the
Gamow shell model which can capture continuum effects. More precisely, we take
advantage of the normal-ordering approach to include the 3NF and the Berggren
representation to treat bound, resonant and continuum states on equal footing
in a complex-momentum plane. In our framework, 3NF is essential to reproduce
the Borromean structure of 17Ne, while the continuum is more crucial for the
halo property of the nucleus. The two-proton halo structure is demonstrated by
calculating the valence proton density and correlation density. The
astrophysically interesting $3/2^-$ excited state has its energy above the
threshold of the proton emission, and therefore the two-proton decay should be
expected from the state.
