HL Tau spectral data cubes + map

We present new NOEMA observations of HL Tau, targeting the following species: CS, H_2_CO, H_2_S, and SO_2_. We produce zeroth-, first-, and second-moment maps for the species where emission was detected and use them to analyse the spatial distribution and kinematic properties of the different molecules in the disk and the envelope. We derive column densities and compare the values derived for the envelope and disk.

We also compute the rotational diagram for the SO_2_ detected transitions. Assuming two different temperature regimes, 17 and 58K, we derive column densities for the species surveyed in the disk and compare them with values derived for the envelope. We find large differences in the derived column density ratios of the molecules surveyed, especially for N(CS)/N(H_2_S), which is 40 to 50 times larger in the envelope.

We attribute these variations to the different excitation and UV-irradiation regimes in the disk and envelope. We also note strong gradients in the ratios between different positions of the disk and tentatively attribute them to different levels of turbulence at different azimuths. The observed differences in molecular ratios in the envelope and the disk are suggestive of chemical reprocessing of the gas during the formation and evolution of the protoplanetary disk.