TY - JOUR
T1 - An analysis of HCN observations of the circumnuclear disc at the Galactic centre
AU - Smith, I. L.
AU - Wardle, M.
PY - 2014/2
Y1 - 2014/2
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84891361558&partnerID=8YFLogxK
U2 - 10.1093/mnras/stt2092
DO - 10.1093/mnras/stt2092
M3 - Article
AN - SCOPUS:84891361558
SN - 0035-8711
VL - 437
SP - 3159
EP - 3171
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -