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In this paper we provide a comprehensive description of the internal dynamics of G0. 253+0. 016 (a. k. a. 'the Brick') ; one of the most massive and dense molecular clouds in the Galaxy to lack signatures of widespread star formation. As a potential host to a future generation of high-mass stars, understanding largely quiescent molecular clouds like G0. 253+0. 016 is of critical importance. In this paper, we reanalyse Atacama Large Millimeter Array cycle 0 HNCO J=4 (0, 4) -3 (0, 3) data at 3 mm, using two new pieces of software which we make available to the community. First, scousepy, a Python implementation of the spectral line fitting algorithm scouse. Secondly, acorns (Agglomerative Clustering for ORganising Nested Structures), a hierarchical n-dimensional clustering algorithm designed for use with discrete spectroscopic data. Together, these tools provide an unbiased measurement of the line of sight velocity dispersion in this cloud, σₕ_₋₎ₒ, { 1D}=4. 42. 1 kms^-1, which is somewhat larger than predicted by velocity dispersion-size relations for the Central Molecular Zone (CMZ). The dispersion of centroid velocities in the plane of the sky are comparable, yielding σₕ_₋₎ₒ, { 1D}/σₕ_₎ₒ, { 1D}1. 20. 3. This isotropy may indicate that the line-of-sight extent of the cloud is approximately equivalent to that in the plane of the sky. Combining our kinematic decomposition with radiative transfer modelling we conclude that G0. 253+0. 016 is not a single, coherent, and centrally-condensed molecular cloud; 'the Brick' is not a brick. Instead, G0. 253+0. 016 is a dynamically complex and hierarchically-structured molecular cloud whose morphology is consistent with the influence of the orbital dynamics and shear in the CMZ.
Henshaw et al. (Sun,) studied this question.