  We present broad-band mid-resolution X-Shooter/VLT spectra for four brown
dwarfs of the TW Hya association. Our targets comprise substellar analogs
representing the different evolutionary phases in young stellar evolution: For
the two diskless brown dwarfs, TWA-26 and TWA-29, we determine the stellar
parameters and we study their chromospheric emission line spectrum. For the two
accreting brown dwarfs, TWA-27 and TWA-28, we estimate the mass accretion rates
from empirical correlations between emission line luminosities and the
accretion luminosity.
