An analysis of HCN observations of the circumnuclear disc at the Galactic centre

I. L. Smith*, M. Wardle

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The Circumnuclear Disc (CND) is a torus of dust and molecular gas rotating about the Galactic Centre and extending from approximately 1.6 pc to 7 pc from the central massive black hole, SgrA*. Large Velocity Gradient modelling of the intensities of the HCN 1-0, 3-2 and 4-3 transitions is used to infer hydrogen density and HCN optical depth. From HCN observations we find the molecular hydrogen density ranges from 0.1 to 2 × 106 cm-3, about an order of magnitude less than inferred previously. The 1-0 line is weakly inverted with line-centre optical depth approx -0.1, in stark contrast to earlier estimates of 4. The estimated mass of the ring is approximately 3-4 × 105 M⊙, consistent with estimates based on thermal dust emission. The tidal shear in the disc implies that star formation is not expected to occur without some significant triggering event.

Original languageEnglish
Pages (from-to)3159-3171
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume437
Issue number4
DOIs
Publication statusPublished - Feb 2014

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