Characterizing the ISM using Fine-Structure Lines in a z=5.7 Hyper-Starburst Galaxy Merger

SPT0346-52 is a gravitationally lensed dusty star-forming galaxy at z~5.7 from the South Pole Telescope sample1. It is an extremely luminous hyper-starburst system with intrinsic far-infrared luminosity > 10¹³ Lsun and star formation rate density ~4200 Msun yr^-1 kpc². Based on ALMA observations of [CII]158 emission, we have determined the prodigious star formation rate density is likely driven by a major merger of two components. Continuing this work, we have ALMA Bands 6 and 7 observations of four fine structure lines in this dusty starforming galaxy: [CII]158, [OI]145, [NII]205, [NII]122. We use a pixelated, interferometric lensing reconstruction code to model the visibilities observed by ALMA and "de-lens" emission to obtain the spatially resolved interstellar medium (ISM) in the source-plane.