The data from the Nobeyama Radio Observatory 45 m telescope Galactic Center CO survey have been analyzed to generate a compilation of molecular clouds with intense CO emission in this region. Clouds are identiÐed in an automated manner through the main part of the survey data for all CO emission peaks exceeding 10 K The measured parameters of identiÐed clouds are analyzed and (T R *). cross-correlated to compare with those of clouds in the Galactic disk. For the clouds in the Galactic center (GC), we Ðnd the scaling laws of the type and which are similar to88, those of clouds in the Galactic disk. All the GC clouds identiÐed have larger velocity widths and virial theorem masses each above the and lines of the disk clouds. We diagnosed gravitational p V -S L CO -M VT stabilities of identiÐed clouds assuming that the disk clouds are nearly at the onset of gravitational instability. All the clouds and cloud complexes in the GC are gravitationally stable, indicating they are in equilibrium with high pressure in the GC environment. Gravitationally less stable clouds follow the main ridge of intense CO emission, part of which deÐne two rigidly rotating molecular arms. The velocity dispersion of a cloud correlates inversely with the degree of gravitational instability. It is concluded that mechanisms such as orbit crowding at the inner Lindblad resonance may promote gravitational instability and subsequent star formation.

We present high-resolution CO images of the Galactic center region taken with the 2 ] 2 focal-plane array receiver mounted on the 45 m telescope of Nobeyama Radio Observatory. We have collected about 44,000 12C16O (J \ 1È0) spectra and over 13,000 13C16O (J \ 1È0) spectra with a 34A (1.4 pc) grid spacing. The 12CO mapping area is roughly and which covers.6, almost the full extent of the molecular gas concentration in the Galactic center. These CO images demonstrate extremely complex distribution and kinematics of molecular gas in the Galactic center. While its large-scale behavior can be attributed to the well-known coherent features, bright CO emission arises from a number of compact (d ¹ 10 pc) clouds with large velocity widths (*V º 30 km s~1 ). The small-scale structure of molecular gas is characterized by Ðlaments, arcs, and shells. The boisterous molecular gas kinematics there may be a result of violent release of kinetic energy by a number of supernova explosions and/or Wolf-Rayet stellar winds.

We consider the high‐energy astrophysics of the inner ∼200 pc of the Galaxy. Our modelling of this region shows that the supernovae exploding here every few thousand years inject enough power to (i) sustain the steady‐state, in situ population of cosmic rays (CRs) required to generate the region’s non‐thermal radio and TeV γ‐ray emission; (ii) drive a powerful wind that advects non‐thermal particles out of the inner Galactic Centre; (iii) supply the low‐energy CRs whose Coulombic collisions sustain the temperature and ionization rate of the anomalously warm envelope detected throughout the Central Molecular Zone; (iv) accelerate the primary electrons which provide the extended, non‐thermal radio emission seen over ∼150 pc scales above and below the plane (the Galactic Centre lobe); and (v) accelerate the primary protons and heavier ions which, advected to very large scales (up to ∼10 kpc), generate the recently identified Wilkinson Microwave Anisotropy Probe (WMAP) haze and corresponding Fermi haze/bubbles. Our modelling bounds the average magnetic field amplitude in the inner few degrees of the Galaxy to the range 60 < B/μ G < 40 0 (at 2σ confidence) and shows that even TeV CRs likely do not have time to penetrate into the cores of the region’s dense molecular clouds before the wind removes them from the region. This latter finding apparently disfavours scenarios in which CRs – in this starburst‐like environment – act to substantially modify the conditions of star formation. We speculate that the wind we identify plays a crucial role in advecting low‐energy positrons from the Galactic nucleus into the bulge, thereby explaining the extended morphology of the 511 keV line emission. We present extensive appendices reviewing the environmental conditions in the Galactic Centre, deriving the star formation and supernova rates there, and setting out the extensive prior evidence that exists, supporting the notion of a fast outflow from the region.

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