Dan Masters -- Investigating the Properties of Emission-Line Galaxies at z~2 with Ground-Based Near-Infrared Spectroscopy

The WFC3 Infrared Spectroscopic Parallels (WISP) survey is using the near-infrared grisms of the Hubble Space Telescope Wide Field Camera 3 to detect star-forming galaxies with minimal bias over 0.3 < z < 2.3. In this talk I will present results from ground-based, near-infrared spectroscopic follow-up of 26 emission-line galaxies at z~2 detected in the WISP survey, obtained with the FIRE spectrograph on the Magellan Baade telescope. The FIRE spectra (R~5000 over 1.0-2.5 micron) enable detailed measurements of physical properties of the z~2 emission-line galaxies, including dust reddening, star formation rate, ionization parameter, kinematics and metallicity. I will discuss the general physical properties of the sample as determined both from individual FIRE spectra and composite spectra derived from the sample. Interestingly, we find evidence for an elevated nitrogen-to-oxygen abundance ratio from the composite FIRE spectrum, which may contribute to the well-known offset of high-redshift star-forming galaxies from the local star-forming sequence in the classical BPT diagram. We speculate that such a nitrogen enhancement may be due to large numbers of Wolf-Rayet stars polluting the ISM in such galaxies.