Cold dust cores in the central zone of the Milky Way
The Milky Way’s central molecular zone (CMZ) spans the innermost 1600 light-years of the galaxy (for comparison, the Sun is 26,600 light-years away from the galactic center) and includes a vast complex of molecular clouds containing about sixty million solar-masses of molecular gas. The gas in these clouds exists under more extreme physical conditions than elsewhere in the galaxy on average, with higher densities and temperatures, more intense pressures, magnetic fields, and turbulence, and higher cosmic-ray abundances and ultraviolet and X-ray radiation. The CMZ is therefore a unique laboratory for studying star formation: not only are these conditions rarely observed in the rest of the Milky Way, they appear to be similar to the conditions in extremely luminous star forming galaxies in the early universe and offer an indirect glimpse into understanding the cosmic history of star formation not otherwise currently possible. However there is a puzzle: the star formation rate in the CMZ is much less than would be expected, barely one-tenth of a solar-mass per year.
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2021-02-19
