Survey of Water and Ammonia in Nearby galaxies (SWAN): Resolved Ammonia
  Thermometry, and Water and Methanol Masers in IC 342, NGC 6946 and NGC 2146
  The Survey of Water and Ammonia in Nearby galaxies (SWAN) studies atomic and
molecular species across the nuclei of four star forming galaxies: NGC\,253,
IC\,342, NGC\,6946, and NGC\,2146. As part of this survey, we present Karl G.
Jansky Very Large Array (VLA) molecular line observations of three galaxies:
IC\,342, NGC\,6946 and NGC\,2146. NGC\,253 is covered in a previous paper.
These galaxies were chosen to span an order of magnitude in star formation
rates and to select a variety of galaxy types. We target the metastable
transitions of ammonia NH$_{3}$(1,1) to (5,5), the 22\,GHz water (H$_2$O)
($6_{16}-5_{23}$) transition, and the 36.1\,GHz methanol (CH$_3$OH)
($4_{-1}-3_{0}$) transition. {We use the NH$_{3}$\ metastable lines to perform
thermometry of the dense molecular gas.} We show evidence for uniform heating
across the central kpc of IC\,342 with two temperature components for the
molecular gas, similar to NGC 253,} of 27\,K and 308\,K, and that the dense
molecular gas in NGC\,2146 has a temperature $<$86 K. We identify two new water
masers in IC\,342, and one new water maser in each of NGC\,6946 and NGC\,2146.
The two galaxies NGC\,253 and NGC\,2146, with the most vigorous star formation,
host H$_2$O kilomasers. Lastly, we detect the first 36\,GHz CH$_3$OH\ masers in
IC\,342 and NGC\,6946. For the four external galaxies the total CH$_3$OH\
luminosity in each galaxy suggests a correlation with galactic star formation
rate, whereas the morphology of the emission is similar to that of HNCO, a weak
shock tracer.
