  We show high resolution spectra of the eclipsing brown dwarf binary
2MASSJ05352184-0546085 taken at the two opposite radial velocity maxima.
Comparisons of the TiO bands to model and template spectra are fully consistent
with the temperatures previously derived for this system. In particular, the
reversal of temperatures with mass - in which the higher-mass primary is cooler
than its companion - is confirmed. We measure the projected rotation velocities
of the compononents; the primary is rotating at least twice as rapidly as the
secondary. At the two radial velocity maxima, Halpha emission lines of both
components stick out to either sides of the Halpha central wavelength, which is
dominated by nebula emission. This enables us to model the individual Halpha
lines of the primary and the secondary. We find that the Halpha emission from
the primary is at least 7 times stronger than the emission from the secondary.
We conclude that the temperature reversal is very likely due to strong magnetic
fields inhibiting convection on the primary.
