Marshall & Lasenby, with collaborators from MPIfEP and Northwestern
University, have been continuing with molecular and radio studies of the
Galactic Centre region (Marshall & Lasenby, 1994a,b,c;
Marshall et al. , 1994a,b). The highly blue-shifted HI gas found by
Yusef-Zadeh, Lasenby and Marshall (1993) was mapped in CO 
using the
JCMT, with spot spectra at other transitions. This showed that the physical
conditions associated with this gas were normal for the large-scale
Galactic gas distribution, thus weakening the evidence that a high-velocity
event uniquely associated with the Galactic Centre was being observed.
Marshall (in press) has developed a maximum entropy method for analysing Zeeman effect
data, which with high enough signal/noise can recover information about the
angle of the field to the line of sight and not just its projected
magnitude. An upper limit on the magnetic field in the circumnuclear disc
(CND) at the Galactic Centre, of 0.5mG, has been obtained by Marshall et al.
(in press), lower than some previous detections. However, it may be
consistent with the previous results if field reversals occur over the
beam size used in the observations.
In addition, the remaining
papers report results from large scale HCN 
and
mapping of the Galactic
Centre carried out on the JCMT. A highlight of this is the
most detailed fit yet to the dynamical parameters of the rotating gas of
the CND. This indicates a significant negative radial velocity , but
intrinsic asymmetry in the distribution of the material might incorrectly
produce this from the model. More reliably, if orbital motion about a point
mass dominates the ring's dynamics, then the inferred magnitude of the
point mass is 
, agreeing well with other estimates of the
mass of a putative black hole at the Galactic Centre.