  The analysis of exoplanetary atmospheres often relies upon the observation of
transit or eclipse events. While very powerful, these snapshots provide mainly
1-dimensional information on the planet structure and do not easily allow
precise latitude-longitude characterisations. The phase curve technique, which
consists of measuring the planet emission throughout its entire orbit, can
break this limitation and provide useful 2-dimensional thermal and chemical
constraints on the atmosphere. As of today however, computing performances have
limited our ability to perform unified retrieval studies on the full set of
observed spectra from phase curve observations at the same time. Here, we
present a new phase curve model that enables fast, unified retrieval
capabilities. We apply our technique to the combined phase curve data from the
Hubble and Spitzer space telescopes of the hot-Jupiter WASP-43 b. We tested
different scenarios and discussed the dependence of our solution to different
assumptions in the model. Our more comprehensive approach suggests that
multiple interpretation of this dataset are possible but our more complex model
is consistent with the presence of thermal inversions and a metal rich
atmosphere, contrasting with previous data analyses, although this likely
depends on the Spitzer data reduction. The detailed constraints extracted here
demonstrate the importance of developing and understanding advanced phase curve
techniques, which we believe will unlock access to a richer picture of
exoplanet atmospheres.
