Scientists create radio atlas of the Milky Way

After almost ten years of work, researchers have drawn up a new radio atlas of the Milky Way.

The atlas is based on observations undertaken with the 25-metre radio telescope in the Chinese city of Urumqi and shows an area of 2,200 square degrees of the sky.

The radio survey covers the northern band of the Milky Way between ten and 230 degrees galactic longitude and between minus five and plus five degrees galactic latitude.

The comprehensive survey shows the polarised radio emission of our galaxy at five gigahertz (corresponding to a wavelength of six centimetres) and thus at the highest frequency every recorded by terrestrial instruments.

The interstellar medium of the Milky Way comprises magnetic fields, electrons, atomic gas and other components, which affect the polarisation plane of the radio emission.

The aim of the project was to map the large-scale magnetic field of the Milky Way. The German and Chinese researchers found a handful of peculiar clumps with very strong, regular magnetic fields and two new supernova remnants each measuring around one degree.

These are the first sources of this type to be discovered with a Chinese radio telescope; astronomers are currently only aware of 270 such objects in the Milky Way.

The researchers were also able to classify two incorrectly identified supernova remnants as thermal radio sources.

The new atlas needed more than 4,500 hours of observations to compile, and its angular resolution is similar to that of the 21-cm wavelength survey of the Milky Way obtained at the 100-metre radio telescope at Effelsberg. 

The study has been published in European journal Astronomy and Astrophysics.