A search for water masers associated with class II methanol masers - I.
  Longitude range 6 to 20 degrees
  The Australia Telescope Compact Array has been used to search for 22-GHz
water masers towards the 119 6.7-GHz methanol masers detected in the Methanol
Multi-Beam survey between Galactic longitudes 6 and 20 degrees; we find water
masers associated with 55 (~46 per cent). Methanol masers with associated water
masers have a higher mean integrated luminosity than those without and there is
a general trend for sources with more luminous 6.7-GHz methanol masers to be
associated with more luminous water maser emission. We have inspected the
GLIMPSE three colour images of the regions surrounding the masers and
cross-matched the maser positions with existing catalogues of Extended Green
Objects and Infrared Dark Clouds. We find more Extended Green Objects at sites
where both methanol and water masers are present than at sites with only
methanol masers, but no significant difference in the fraction embedded within
Infrared Dark Clouds. Analysis of the 1.1-mm dust emission shows dust clumps
associated with masers that have greater flux densities and higher column
densities than those without. Dust clumps associated with both water and
6.7-GHz methanol masers are generally the most compact clumps followed by those
associated with only methanol then the clumps without associated maser
emission. We conclude that protostars with both methanol and water masers are
often older than those with only methanol, however, we suggest that the
evolutionary phase traced by water masers is not as well defined as for 6.7-GHz
methanol masers.
