A self-consistent, absolute isochronal age scale for young moving groups
  in the solar neighbourhood
  We present a self-consistent, absolute isochronal age scale for young (< 200
Myr), nearby (< 100 pc) moving groups in the solar neighbourhood based on
homogeneous fitting of semi-empirical pre-main-sequence model isochrones using
the tau^2 maximum-likelihood fitting statistic of Naylor & Jeffries in the M_V,
V-J colour-magnitude diagram. The final adopted ages for the groups are:
149+51-19 Myr for the AB Dor moving group, 24+/-3 Myr for the {\beta} Pic
moving group (BPMG), 45+11-7 Myr for the Carina association, 42+6-4 Myr for the
Columba association, 11+/-3 Myr for the {\eta} Cha cluster, 45+/-4 Myr for the
Tucana-Horologium moving group (Tuc-Hor), 10+/-3 Myr for the TW Hya
association, and 22+4-3 Myr for the 32 Ori group. At this stage we are
uncomfortable assigning a final, unambiguous age to the Argus association as
our membership list for the association appears to suffer from a high level of
contamination, and therefore it remains unclear whether these stars represent a
single population of coeval stars.
  Our isochronal ages for both the BPMG and Tuc-Hor are consistent with recent
lithium depletion boundary (LDB) ages, which unlike isochronal ages, are
relatively insensitive to the choice of low-mass evolutionary models. This
consistency between the isochronal and LDB ages instills confidence that our
self-consistent, absolute age scale for young, nearby moving groups is robust,
and hence we suggest that these ages be adopted for future studies of these
groups.
  Software implementing the methods described in this study is available from
http: //www.astro.ex.ac.uk/people/timn/tau-squared/.
