Interferometry of class I methanol masers, statistics and the distance
  scale
  The Australia Telescope Compact Array (ATCA) participated in a number of
survey programs to search for and image common class I methanol masers (at 36
and 44 GHz) with high angular resolution. In this paper, we discuss spatial and
velocity distributions revealed by these surveys. In particular, the number of
maser regions is found to fall off exponentially with the linear distance from
the associated young stellar object traced by the 6.7-GHz maser, and the scale
of this distribution is 263+/-15 milliparsecs. Although this relationship still
needs to be understood in the context of the broader field, it can be utilised
to estimate the distance using methanol masers only. This new technique has
been analysed to understand its limitations and future potential. It turned
out, it can be very successful to resolve the ambiguity in kinematic distances,
but, in the current form, is much less accurate (than the kinematic method) if
used on its own.
