Stars form in the dense regions of giant molecular clouds – huge structures made mostly of hydrogen. These clouds are affected by many factors, some that are local such as gravity and turbulence and others that are galaxy-wide such as mergers. Now, a new study has produced stunning images of these magnetic fields.
The images were created using data from the European Space Agency's Herschel and Planck space telescopes. The telescopes looked at wavelengths of light that we cannot see with our naked eye. Herschel observed the infrared universe, where the cold interstellar clouds of gas suddenly appear bright. Planck's main mission was to study the Cosmic Microwave Background, but its all-sky observations were also used to learn more about these clouds.
Published in Astronomy & Astrophysics, the Planck data was used to locate the magnetic fields, while the Herschel observations were used to measure the density of the clouds.
The data showed that magnetic field lines are perpendicular to the densest part of the gas filaments, suggesting that the magnetic field plays an important role in how interstellar material is arranged around giant molecular clouds. The team also found no correlation between the magnetic field and the star formation rate. When it comes to making new stars, other factors must be dominant.
The study also explored for several other nearby molecular clouds the connection between the density of the gas in the filaments and the magnetic fields around them, including well-known examples such as the Orion A Molecular Cloud and the Aquila Rift. All these clouds were located just 1,500 light-years from the solar system.
Both Herschel and Planck finished their mission in 2013, but new discoveries from their observations will likely continue for years to come.
More images are available on the European Space Agency website.