Global Star Formation Rate Density over 0.7 < z < 1.9

May 2009 • 2009ApJ...696..785S

Authors • Shim, Hyunjin • Colbert, James • Teplitz, Harry • Henry, Alaina • Malkan, Mattew • McCarthy, Patrick • Yan, Lin

Abstract • We determine the global star formation rate (SFR) density at 0.7 < z < 1.9 using emission-line-selected galaxies identified in Hubble Space Telescope-Near Infrared Camera and Multi-Object Spectrograph (HST-NICMOS) grism spectroscopy observations. Observing in a pure parallel mode throughout HST Cycles 12 and 13, our survey covers ~104 arcmin² from which we select 80 galaxies with likely redshifted Hα emission lines. In several cases, a somewhat weaker [O III] doublet emission is also detected. The Hα luminosity range of the emission-line galaxy sample is 4.4 × 10⁴¹ < L(Hα) < 1.5 × 10⁴³ erg s^-1. In this range, the luminosity function is well described by a Schechter function with phi* = (4.24 ± 3.55) × 10^-3 Mpc^-3, L* = (2.88 ± 1.58) × 10⁴² erg s^-1, and α = -1.39 ± 0.43. We derive a volume-averaged SFR density of 0.138 ± 0.058 M _sun yr^-1 Mpc^-3 at z = 1.4 without an extinction correction. Subdividing the redshift range, we find SFR densities of 0.088 ± 0.056 M _sun yr^-1 Mpc^-3 at z = 1.1 and 0.265 ± 0.174 M _sun yr^-1 Mpc^-3 at z = 1.6. The overall star formation rate density is consistent with previous studies using Hα when the same average extinction correction is applied, confirming that the cosmic peak of star formation occurs at z > 1.5.

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IPAC Authors
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James Colbert

Associate Scientist

Harry Teplitz

Senior Scientist