  We present observations of electron energization in magnetic reconnection
outflows during the pre-impulsive phase of solar flare SOL2012-07-19T05:58.
During a time-interval of about 20 minutes, starting 40 minutes before the
onset of the impulsive phase, two X-ray sources were observed in the corona,
one above the presumed reconnection region and one below. For both of these
sources, the mean electron distribution function as a function of time is
determined over an energy range from 0.1~keV up to several tens of keV, for the
first time. This is done by simultaneous forward fitting of X-ray and EUV data.
Imaging spectroscopy with RHESSI provides information on the high-energy tail
of the electron distribution in these sources while EUV images from SDO/AIA are
used to constrain the low specific electron energies. The measured electron
distribution spectrum in the magnetic reconnection outflows is consistent with
a time-evolving kappa-distribution with $\kappa =3.5-5.5$. The spectral
evolution suggests that electrons are accelerated to progressively higher
energies in the source above the reconnection region, while in the source
below, the spectral shape does not change but an overall increase of the
emission measure is observed, suggesting density increase due to evaporation.
The main mechanisms by which energy is transported away from the source regions
are conduction and free-streaming electrons. The latter dominates by more than
one order of magnitude and is comparable to typical non-thermal energies during
the hard X-ray peak of solar flares, suggesting efficient acceleration even
during this early phase of the event.
