The magnetic fields can affect star formation, regulate the propagation of high-energy particles, and help establish the gas presence to the surrounding halo. Still, little is known about the galactic magnetic field. The geometry and strength of the magnetic field in the galactic halo are a metaphoric nebula. A globular cluster might help us shed more light on the galactic magnetic field.
A study made by an international research team led by Federico Abbate from the Max Planck Institute for Radio Astronomy in Bonn, Germany, is trying to change that. Its purpose is to spread the shadow of ignorance on the galactic magnetic field using the observation of globular cluster 47 Tucanae.
A globular cluster is a spherical collection of stars that orbits a galactic core. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes, and relatively high stellar densities toward their centers.
About the New Globular Cluster Research and The Galactic Magnetic Field
Globular clusters are found in the halo of a galaxy and contain considerably more stars. Globular clusters are relatively common; there are about 150 to 158 currently known globular clusters in the Milky Way, with perhaps 10 to 20 more still undiscovered.
The so-called 47 Tucanae, or 47 Tuc, is a globular cluster located in the constellation Tucana, 15,000 light-years away. The cluster may contain an intermediate-mass black hole. 47 Tucanae is the second brightest globular cluster in the sky (after Omega Centauri). It is one of the most massive globular clusters in the Galaxy, containing millions of stars.
It is one of the most studied globular clusters, with 25 pulsars known so far. Their activity proved the presence of gas in the cluster. Recent observations with the Parkes radio telescope in Australia measured the pulsars’ polarized radio emission and their Faraday rotation. These revealed the powerful presence of a magnetic field in 47 Tuc.
The magnetic field is maintained with the help of the galactic wind, perpendicular to the galactic disk. Its strength is given by the shock-wave kind of interaction between the cluster and the galactic wind.