The Immersion Grating Infrared Spectrometer (IGRINS) is a revolutionary instrument that exploits broad spectral coverage at high-resolution (R=45,000) in the near-infrared. IGRINS employs a silicon immersion grating as the primary disperser of the white pupil, and volume-phase holographic gratings cross-disperse the H and K bands onto Teledyne Hawaii-2RG arrays. IGRINS provides simultaneous wavelength coverage from 1.45 - 2.45 microns in a compact cryostat. I will summarize the performance and various science programs carried out at McDonald Observatory since commissioning in Summer 2014, and current status operating with Discovery Channel Telescope from this Summer. With IGRINS we have observed Solar System objects, nearby young stars, star-forming regions like Taurus and Ophiuchus, the Galactic Center, and planetary nebulae. 

The second half of my talk will be focused on the study of ionized and neutral gas in an ultracompact HII (UCHII) region Monoceros R2 (Mon R2). We obtained the IGRINS spectra of Mon R2 to study the kinematic patterns in the areas where ionized and molecular gases interact. The position-velocity maps from the IGRINS spectra demonstrate that the ionized gases (Brackett and Pfund series, He and Fe emission lines;Δv ≈ 40km/s) flow along the walls of the surrounding clouds. This is consistent with the model by Zhu et al. (2005, 2008). In the PV maps of the H2 emission lines there is no obvious motion (Δv < ~10km/s) of the molecular hydrogen right at the ionization boundary. This implies that the molecular gas is not taking part in the flow as the ionized gas is moving along the cavity walls.