Abstract
We present the results of a survey which utilizes the NICMOS Camera 3 Parallel grism and imaging observations of random fields. We have identified 33 H alpha emission-line galaxies at 0.75 < z < 1.9. The inferred co-moving number, density of these objects is 3.3 x 10(-4) h(50)(3), Mpc(-3), very similar to that of the bright Lyman break objects at z similar to 3. The mean star formation rate of these galaxies 21 M. yr(-1) for H-0 = 50km/s/Mpc. Using this sample, we derived the H alpha luminosity function (LF) at z = 1.3. The integrated H alpha luminosity density at z similar to 1.3 is 1.64 x 10(40) h(50) erg s(-1) Mpc(-3), approximately 14 times greater than the local value reported by Gallego et al. (1995). The volume averaged star formation rate at 1.3 +/- 0.5 is 0.13 M. yr(-1) Mpc(-3) without correction for extinction. The SFR derived at similar to 6500 Angstrom is a factor of 3 higher than that deduced from 2800 Angstrom continua. We believe that this difference is largely due to dust extinction. The implied total extinction at 2800 Angstrom is in the range of 2 - 4 magnitude. However, the precise determination of the total extinction is sensitive to the model assumptions.