First detection of thermal radio jets in a sample of proto-brown dwarf
  candidates
  We observed with the JVLA at 3.6 and 1.3 cm a sample of 11 proto-brown dwarf
candidates in Taurus in a search for thermal radio jets driven by the most
embedded brown dwarfs. We detected for the first time four thermal radio jets
in proto-brown dwarf candidates. We compiled data from UKIDSS, 2MASS, Spitzer,
WISE and Herschel to build the Spectral Energy Distribution (SED) of the
objects in our sample, which are similar to typical Class~I SEDs of Young
Stellar Objects (YSOs). The four proto-brown dwarf candidates driving thermal
radio jets also roughly follow the well-known trend of centimeter luminosity
against bolometric luminosity determined for YSOs, assuming they belong to
Taurus, although they present some excess of radio emission compared to the
known relation for YSOs. Nonetheless, we are able to reproduce the flux
densities of the radio jets modeling the centimeter emission of the thermal
radio jets using the same type of models applied to YSOs, but with
corresponding smaller stellar wind velocities and mass-loss rates, and
exploring different possible geometries of the wind or outflow from the star.
Moreover, we also find that the modeled mass outflow rates for the bolometric
luminosities of our objects agree reasonably well with the trends found between
the mass outflow rates and bolometric luminosities of YSOs, which indicates
that, despite the "excess" centimeter emission, the intrinsic properties of
proto-brown dwarfs are consistent with a continuation of those of very low mass
stars to a lower mass range. Overall, our study favors the formation of brown
dwarfs as a scaled-down version of low-mass stars.
