Universe

Astronomers Have Created Most Detailed Map of Milky Way to Date

October 20, 2016 | West Virginia University

his HI4PI map was produced using data from the 100-m Max-Planck radio telescope in Effelsberg, Germany and the 64-m CSIRO radio telescope in Parkes, Australia. The image colors reflect gas at differing velocities. The plane of the Milky Way runs horizontally across the middle of the image. The Magellanic Clouds can be seen at the lower right.

Photo credit: Benjamin Winkel, Max Planck Institute, and the HI4PI collaboration

Hydrogen. Atomic number 1. It is the simplest and lightest element on the periodic table, but don't be fooled by its humble appearance. With just a single proton and a single electron, it is the most abundant element in the universe and has fueled star formation for the past 13 billion years.

Now scientists -- including an astrophysicist from West Virginia University -- have mapped the key ingredient's distribution across the Milky Way, revealing details about our galaxy that have never been seen before.

The new map is the result of work by a team of scientists from around the world, including D.J. Pisano, associate professor of physics and astronomy in the Eberly College of Arts and Sciences. The research was published today in the journal Astronomy and Astrophysics.

The HI4PI survey collected data on clouds of hydrogen gas at full resolution, allowing scientists to learn more about the physics of what is going on in those areas, where the structures are coming from and more.

Pronounced "hi four pie," referring to the astrophysical abbreviation for neutral hydrogen (HI) and the geometrical reference to the whole sky (4*PI), the survey allows scientists to study all directions of the sky.

The team used two of the world's largest fully steerable radio telescopes -- Parkes Observatory in Australia and the Effelsberg 100m Radio Telescope in Germany.

Due to their sheer size and other technical characteristics these scientific instruments are highly sensitive. They can see deep into space, allowing scientists to study parts of the universe that are often invisible or hidden.

The team used the two telescopes to survey from both the northern and southern hemispheres. Because scientists collected the data from two different telescopes, astronomers in Germany did additional data processing to produce a combined, consistent map.

"The scope of the survey -- the entire sky -- couldn't have been done without collaboration with scientists from around the world," said Pisano.

The study required more than a million individual observations and about 10 billion individual data points. Pisano and his collaborators in the Galactic All Sky Survey in Australia spent more than 2,000 hours over two years using the Parkes telescope to map the sky south of the equator.