The physical parameters of clumps associated with class I methanol
  masers
  We present a study of the association between class I methanol masers and
cold dust clumps from the ATLASGAL survey. It was found that almost 100% of
class I methanol masers are associated with objects listed in the ATLASGAL
compact source catalog. We find a statistically significant difference in the
flux density, luminosity, number and column density and temperature
distributions of ATLASGAL sources associated with 95/44 GHz methanol masers
compared with those ATLASGAL sources devoid of 95 GHz methanol masers. The
masers tend to arise in clumps with higher densities, luminosities and
temperatures compared with both the full sample of the ATLASGAL clumps, as well
as the sample of ATLASGAL sources that were cross-matched with positions
previously searched for methanol masers but with no detections. Comparison
between the peak position of ATLASGAL clumps and the interferometric positions
of the associated class I and II methanol masers reveals that class I masers
are generally located at larger physical distances from the peak submillimetre
emission than class II masers. We conclude that the tight association between
ATLASGAL sources and class I methanol masers may be used as a link toward
understanding the conditions of the pumping of these masers and evolutionary
stages at which they appear.
