Water Masers Associated with Star Formation in the Antennae Galaxies
  We present Very Large Array observations with 80 milliarcsecond resolution
(~9 pc) of the recently discovered Galactic-analog water masers in the Antennae
interacting galaxies (NGC 4038/NGC 4039; Arp244). Three regions of water maser
emission are detected: two in the ``interaction region'' (IAR) and the third
~5.6'' (> 600 pc) west of the NGC 4039 nucleus. The isotropic water maser
luminosities range from 1.3 to 7.7 L_sun. All three maser regions are mostly
obscured in the optical/near-infrared continuum, and are coincident with
massive CO-identified molecular clouds. The water maser velocities are in
excellent agreement with those of the molecular gas. We also present archival
VLA 3.6 cm data with ~0.28" (~30 pc) and ~0.8" (~90 pc) resolution toward the
maser locations. All three maser regions are coincident with compact 3.6 cm
radio continuum emission, and two are dominated by thermal ionized gas,
suggesting the presence of natal super star clusters containing the equivalent
of a few thousand O stars. We also present detailed comparisons between the
radio data and existing HST ACS (optical) and NICMOS (near-IR) data and find
that both maser regions in the IAR are also associated with Pa\alpha emission
and neither source is detected shortward of 2 microns. These results highlight
the potential of using Galactic-analog water masers to pinpoint sites of young
super star cluster formation with exquisite angular resolution.
