  A narrowband imaging survey of 276 square minutes of arc was carried out at
near infrared wavelengths to search for emission line objects at high
redshifts. Most of the fields contained a known quasar or radio galaxy at a
redshift that placed one of the strong, restframe optical emission lines
(H-alpha, [O III], H-beta, or [O II]) in the bandpass of the narrowband filter.
The area weighted line flux limit over the entire survey was 3.4x10e-16
erg/cm2/s (3-sigma), while the most sensitive limits reached 1.4x10e-16
erg/cm2/s. Integrating the volume covered by all four optical emission lines in
each image yields a total comoving volume surveyed of 1.4x10e5 cubic
megaparsecs. Considering only H-alpha emission in the K band (2.05 < z < 2.65),
where the survey is most sensitive, the survey covered a comoving volume of
3.0x10e4 cubic megaparsecs to a volume-weighted average star formation rate of
112 M-solar/yr (for Ho = 50 km/s/Mpc, Omega = 1). This is the most extensive
near-infrared survey which is deep enough to have a reasonable chance at
detecting strong line emission from an actively star-forming population of
galaxies, when d against simple models of galaxy formation. One emission line
candidate was identified in this survey, and subsequently confirmed
spectroscopically.
