@article { , title = {Ammonia in the interstellar medium of a starbursting disc at z = 2.6}, abstract = {We report the detection of the ground state rotational emission of ammonia, ortho-NH3 (JK = 10 → 00) in a gravitationally lensed intrinsically hyperluminous star-bursting galaxy at z = 2.6. The integrated line profile is consistent with other molecular and atomic emission lines which have resolved kinematics well modelled by a 5 kpc-diameter rotating disc. This implies that the gas responsible for NH3 emission is broadly tracing the global molecular reservoir, but likely distributed in pockets of high density (n ≳ 5 × 104 cm−3). With a luminosity of 2.8 × 106 L☉, the NH3 emission represents 2.5 × 10−7 of the total infrared luminosity of the galaxy, comparable to the ratio observed in the Kleinmann-Low nebula in Orion and consistent with sites of massive star formation in the Milky Way. If LNH3/LIR serves as a proxy for the 'mode' of star formation, this hints that the nature of star formation in extreme starbursts in the early Universe is similar to that of Galactic star-forming regions, with a large fraction of the cold interstellar medium in this state, plausibly driven by a storm of violent disc instabilities in the gas-dominated disc. This supports the 'full of Orions' picture of star formation in the most extreme galaxies seen close to the peak epoch of stellar mass assembly.}, doi = {10.1093/mnrasl/slac111}, eissn = {1745-3933}, issue = {1}, journal = {Monthly Notices of the Royal Astronomical Society: Letters}, pages = {L60-L64}, publicationstatus = {Published}, publisher = {Oxford University Press (OUP)}, url = {https://nottingham-repository.worktribe.com/output/11756183}, volume = {517}, keyword = {Space and Planetary Science, Astronomy and Astrophysics}, year = {2022}, author = {Doherty, M. J. and Geach, J. E. and Ivison, R. J. and Menten, K. M. and Jacob, A. M. and Forbrich, J. and Dye, S.} }