Constraints on the presence of water megamaser emission in z~2.5
  ultraluminous infrared starburst galaxies
  We present Expanded Very Large Array and Arecibo observations of two lensed
submm galaxies at z~2.5, in order to search for redshifted 22.235 GHz water
megamaser emission. Both SMM J14011+0252 and SMM J16359+6612 have
multi-wavelength characteristics consistent with ongoing starburst activity, as
well as CO line emission indicating the presence of warm molecular gas. Our
observations do not reveal any evidence for H2O megamaser emission in either
target, while the lensing allows us to obtain deep limits to the H_2O line
luminosities, L(H2O) < 7470 Lsun (3-sigma) in the case of SMM J14011+0252, and
L(H2O) < 1893 Lsun for SMM J16359+6612, assuming linewidths of 80 km/s. Our
search for, and subsequent non-detection of H2O megamaser emission in two
strongly lensed starburst galaxies, rich in gas and dust, suggests that such
megamaser emission is not likely to be common within the unlensed population of
high-redshift starburst galaxies. We use the recent detection of strong H2O
megamaser emission in the lensed quasar, MG J0414+0534 at z = 2.64 to make
predictions for future EVLA C-band surveys of H2O megamaser emission in submm
galaxies hosting AGN.
