Accretion and outflow activity in proto-brown dwarfs
  We present a near-infrared study of accretion and outflow activity in 6 Class
0/I proto-brown dwarfs (proto-BDs) using VLT/SINFONI spectroscopy and
spectro-imaging observations. The spectra show emission in several [FeII] and
H$_{2}$ lines associated with jet/outflow activity, and in the accretion
diagnostics of Pa$\beta$ and Br$\gamma$ lines. The peak velocities of the
[FeII] lines ($>$100 km s$^{-1}$) are higher than the H$_{2}$ lines. The Class
0 proto-BDs show strong emission in the H$_{2}$ lines but the [FeII] lines are
undetected, while the Class I objects show emission in both [FeII] and H$_{2}$
lines, suggesting an evolutionary trend in the jets from a molecular to an
ionic composition. Extended emission with knots is seen in the [FeII] and
H$_{2}$ spectro-images for 3 proto-BDs, while the rest show compact
morphologies with a peak on-source. The accretion rates for the proto-BDs span
the range of (2$\times$10$^{-6}$ -- 2$\times$10$^{-8}$) Msun yr$^{-1}$, while
the mass loss rates are in the range of (4$\times$10$^{-8}$ --
5$\times$10$^{-9}$) Msun yr$^{-1}$. These rates are within the range measured
for low-mass protostars and higher than Class II brown dwarfs. We find a
similar range in the jet efficiency for proto-BDs as measured in protostars. We
have performed a study of the Brackett decrement from the Br7-Br19 lines
detected in the proto-BDs. The upper Brackett lines of Br13-Br19 are only
detected in the earlier stage systems. The ratios of the different Brackett
lines with respect to the Br$\gamma$ line intensity are consistent with the
ratios expected from Case B recombination.
