Abstract
The detection of 22 GHz water vapor emission from IC 342 is reported, raising the detection rate among northern galaxies with IRAS point source fluxes $S_{\rm 100\,\mu m} > 50$ Jy to 16%. The maser, associated with a star forming region ~10–15´´ west of the nucleus, consists of a single 0.5 km s-1 wide feature and reaches an isotropic luminosity of 10-2 $L_{\odot}$ ($D=1.8$ Mpc). If the time variability is intrinsic, the maser size is $\la$ $1.5\times10^{16}$ cm ($\la$0.5 mas) which corresponds to a brightness temperature of $\ga$109 K. The linewidth, luminosity, and rapid variability are reminiscent of the 8 km s-1 super maser in Orion-KL. A velocity shift of 1 km s-1 within two weeks and subsequent rapid fading is explained in terms of a chance alignment of two dense molecular clouds. Observations at 22 GHz toward Maffei 2 are also reported, yielding a 5σ upper limit of 25 mJy for a channel spacing of 1.05 km s-1.