  Based on high-resolution spectra obtained with PHOENIX at Gemini-South,
CRIRES at VLT-UT1, and ESPaDOnS at CFHT, we present new measurements of the
radial and projected rotational velocities of 219 low-mass stars. The target
likely membership was initially established using the Bayesian analysis tool
recently presented in \citet{2013malo}, taking into account only the position,
proper motion and photometry of the stars to assess their membership
probability. In the present study, we include radial velocity as an additional
input to our analysis, and in doing so we confirm the high membership
probability for 130 candidates: 27 in $\beta$ Pictoris, 22 in
Tucana-Horologium, 25 in Columba, 7 in Carina, 18 in Argus and 18 in AB Doradus
and 13 with an ambiguous membership. Our analysis also confirms the membership
of 57 stars proposed in the literature. A subsample of 16 candidates was
observed at three or more epochs, allowing us to discover 6 new spectroscopic
binaries. The fraction of binaries in our sample is 25%, consistent with values
in the literature. Twenty percent of the stars in our sample show projected
rotational velocities (\vsini) higher than 30 \kms\ and therefore are
considered as fast rotators. A parallax and other youth indicators are still
needed to fully confirm the 130 highly probable candidates identified here as
new {\it bona fide} members. Finally, based on the X-ray emission of {\it bona
fide} and highly probable group members, we show that for low-mass stars in the
12-120 Myr age range, the X-ray luminosity is an excellent indicator of youth
and better than the more traditionally used R$_{\rm X}$ parameter, the ratio of
X-ray to bolometric luminosity.
