The ESA-NASA Planck spacecraft has returned new remarkable images showing previously undiscovered islands of star formation and a mysterious haze of microwave emissions in our Milky Way galaxy.
This all-sky image shows the distribution of carbon monoxide as seen by Planck in blue and a compilation of previous surveys in red (ESA / Planck Collaboration / T. Dame et al.)
According to the European Space Agency, these images allowed scientists to create the first map to show carbon monoxide over the whole sky.
Carbon monoxide is a constituent of the cold clouds that populate the Milky Way and other galaxies. Predominantly made of hydrogen molecules, these clouds provide the reservoirs from which stars are born.
However, hydrogen molecules are difficult to detect because they do not readily emit radiation. Carbon monoxide forms under similar conditions and, even though it is much rarer, it emits light more readily and therefore is more easily detectable. So, astronomers use it to trace the clouds of hydrogen.
“Planck turns out to be an excellent detector of carbon monoxide across the entire sky,” said Dr. Jonathan Aumont, Planck collaborator at the Institut d’Astrophysique Spatiale, France.
Planck spacecraft has also discovered a mysterious haze of microwaves that presently defies explanation.
“The images reveal two exciting aspects of the galaxy in which we live,” said Dr. Krzysztof Gorski, Planck scientist at NASA’s Jet Propulsion Laboratory in Pasadena and Warsaw University Observatory, Poland. “They show a haze around the center of the galaxy, and cold gas where we never saw it before.”
This all-sky image shows the spatial distribution over the whole sky of the Galactic Haze at 30 and 44 GHz (ESA / Planck Collaboration)
The galactic haze comes from the region surrounding the galactic center and looks like a form of energy called synchrotron emission. This is produced when electrons pass through magnetic fields after having been accelerated by supernova explosions.
It shows what astronomers call a ‘harder’ spectrum: its emission does not decline as rapidly with increasing energies.
Scientists have proposed several theories to explain this unusual behavior, including higher supernova rates, galactic winds and even the annihilation of dark-matter particles. However, none of them has been confirmed and it remains puzzling.
“The results achieved thus far by Planck on the galactic haze and on the carbon monoxide distribution provide us with a fresh view on some interesting processes taking place in our Galaxy,” said Dr. Jan Tauber, ESA’s Project scientist for Planck.
