Variability in extragalactic class I methanol masers: New maser
  components toward NGC4945 and NGC253
  We have used the Australia Telescope Compact Array (ATCA) to make new
observations of the 36.2-GHz ($4_{-1}\rightarrow3_0$E) methanol transition
toward NGC 4945 and NGC 253. These observations have revealed the presence of
new maser components toward these galaxies, and have provided the first clear
evidence for variability in extragalactic class~I methanol masers. Alongside
the new observations of NGC 4945 and NGC 253, we present the results of recent
36.2-GHz methanol maser searches toward 12 galaxies, placing upper limits on
the emission from the 36.2-GHz class~I transition and the 37.7-GHz
($7_{2}\rightarrow8_1$E) class~II maser line toward these sources. Flux density
values for the 7-mm continuum emission toward these sources are also reported
where applicable. A re-analysis of the published 36.2-GHz methanol observations
of Arp 220 undertaken as part of the search revealed some issues with previous
imaging procedures. The re-analysis, combined with non-detections in
independent follow-up observations suggest that there is no 36.2-GHz methanol
emission toward Arp 220 stronger than 3.5 mJy in a 10 km s$^{-1}$ channel
(5$\sigma$ upper limit).
