The Molecular ISM in the Super Star Clusters of the Starburst NGC 253

摘要: We present submillimeter spectra of the (proto-)super star cluster (SSC) candidates in starbursting center nearby galaxy NGC 253 identified by Leroy et al. (2018). The 2.5pc resolution our ALMA cycle 3 observations approach size SSCs and allows study physical chemical properties molecular gas these sources. In 14 SSC sources frequency ranges 342.0-345.8 GHz 353.9-357.7 we detect 55 lines belonging to 19 different species. differ significantly complexity, with richest clusters showing species least complex 4 HCN isotopologues isomers (H$^{13}$CN, HC$^{15}$N, H$^{15}$NC), abundant HC$_3$N, SO S$^{18}$O, SO$_2$, H$_2$CS. ratios CO/HCN, CO/HCO$^+$ are low, ~1-10, implying high dense fractions SSCs. Line ratio analyses suggests chemistry consistent photon-dominated regions mechanical heating. None near show line that imply an X-ray dominated region, suggesting heating any (still unknown) AGN does not play a major role. temperatures most sources, average rotational temperature ~130 K SO$_2$. widespread existence vibrationally excited HC$_3$N transitions implies strong IR radiation fields, potentially trapped greenhouse effect due continuum opacities.