Herschel’s cameras combine to show the galaxy in a new light

The new pictures unveil a small part of our Milky Way Galaxy as we have never seen it before.Provided by the Science and Technology Facilities Council, United Kingdom
By | Published: October 2, 2009 | Last updated on May 18, 2023
Milky Way with SPIRE/PACS cameras
In this image the SPIRE and PACS images have been combined into a single composite. The blue denotes 70 microns, the green 160 microns, and the red is the combination of the emission from all three SPIRE bands at 250/350/500 microns.
October 2, 2009
The Herschel Space Observatory has produced spectacular new images of interstellar material in our galaxy, using the Spectral and Photometric Imaging Receiver (SPIRE) camera in tandem with Herschel’s other camera, Photodetector Array Camera & Spectrometer (PACS).

The new pictures, made during the first trial run with the two instruments operating at the same time, unveil a small part of our Milky Way Galaxy as we have never seen it before.

Keith Mason, Chief Executive of the Science and Technology Facilities Council (STFC), said SPIRE produced spectacular images. “This sophisticated camera is evidence of the skill and cutting-edge technology we have here in the United Kingdom and is set to vastly expand our knowledge of the early stages of our universe.”

The SPIRE camera responds to light at wavelengths between 250 and 500 microns (millionths of a meter) — 500-1000 times longer than the wavelength of visible light. PACS covers wavelengths between 70 and 170 microns. Together they provide detailed images in five different far infrared colors, not only revealing new material in the galaxy, but providing astronomers with a wealth of information about it — such as how much material there is, its mass, temperature and composition, and whether or not some of it is collapsing to form new stars. Stars form in cold, dense environments, and the composite images locate the star-forming regions that would be very difficult to isolate from a map made at a single far-infrared or submillimeter wavelength.

The two instruments have imaged an area of about 2° x 2° (about 16 times as big as the size of the Moon as seen from Earth), revealing an extremely rich reservoir of cold material in the galactic plane that is seen to be in a previously unsuspected state of turmoil. The interstellar material is condensing in a continuous and interconnected maze of filaments and strings of newly forming stars in all stages of development, unveiling a tireless galaxy constantly forging new generations of stars. We see an intricate network of filamentary structures with surprising features indicative of a chain of near-simultaneous star-formation events, glittering rather like beads of water on a string in the sunlight.

Large areas of the Milky Way will be surveyed systematically by Herschel in this manner, helping astronomers to unravel the mysteries of star formation in a way that has never been previously possible. With the two instruments operating at the same time, the observations can be made with great efficiency.

“We had high hopes for this kind of observation with Herschel, using the combined power of the two cameras to see the galaxy as never before,” said Matt Griffin of Cardiff University in the United Kingdom who is the SPIRE principal investigator. “It’s great to see that the observations work so well from a technical point of view, and that the scientific results are so spectacular. It appears that star formation in the galaxy is a very turbulent process.”

“These images show SPIRE and PACS working together in perfect harmony, something that will be needed not only for studies of our own galaxy, but also for Herschel’s large studies of galaxy evolutionm” said David Clements from the SPIRE team at Imperial College London’s Department of Physics.”