A lower limit of 50 microgauss for the magnetic field near the Galactic Centre.

The amplitude of the magnetic field near the Galactic Centre has been uncertain by two orders of magnitude for several decades. On a scale of approximately 100 parsecs (pc), fields of approximately 1,000 microgauss (microG; refs 1-3) have been reported, implying a magnetic energy density more than 10,000 times stronger than typical for the Galaxy. Alternatively, the assumption of pressure equilibrium between the various phases of the Galactic Centre interstellar medium (including turbulent molecular gas, the contested 'very hot' plasma, and the magnetic field) suggests fields of approximately 100 microG over approximately 400 pc size scales.