HCN J = 4-3, HNC J = 1-0, H¹³CN J = 1-0, and HC₃N J = 10-9 Maps of the Galactic Center Region. I. Spatially Resolved Measurements of Physical Conditions and Chemical Composition

This supplement paper presents the maps of HCN J = 4-3, HNC J = 1-0, J = 1-0, and HC₃N J = 10-9 for the Galactic central molecular zone (CMZ), which have been obtained using the Atacama Submillimeter Telescope Experiment and Nobeyama Radio Observatory 45 m telescope. Three-dimensional maps (2D in space and 1D in velocity) of the gas kinetic temperature (T _kin), hydrogen volume density (nH₂), and fractional abundances of eight molecules (HCN, HNC, , HCO⁺, H₂CO, SiO, CS, and ) have been constructed from our and archival data. We have developed a method with hierarchical Bayesian inference for this analysis, which has successfully suppressed the artificial correlations among the parameters created by systematic errors due to the deficiency in the simple one-zone excitation analysis and the calibration uncertainty. The typical values of T _kin and nH₂ are 10^1.8 K and 10^4.2 cm^-3, respectively, and the presence of an additional cold, low-density component is also indicated. The distribution of high-temperature regions is poorly correlated with known active star-forming regions, while a few of them coincide with shocked clouds. Principal component analysis has identified two distinct groups in the eight analyzed molecules: one group with large PC1 and PC2 scores, and the other with a large T _kin dependence, which could be explained using two regimes of shock chemistry with fast (≳20 km s^-1) and slow (≳20 km s^-1) velocity shocks, respectively. This supports the idea that the mechanical sputtering of dust grains and the mechanical heating play primary roles in the chemical and thermal processes in CMZ clouds.