Article Posted on : - Oct 05, 2009

The SPIRE and PACS images captured by the Herschel Space Observatory. Image credit: ESA

PARIS (BNS): The Herschel Space Observatory has zoomed in on a dark, cold region of our Milky Way galaxy, capturing the “bustling” activities going on there.

The newly snapped images provide spectacular vistas of cold gas clouds lying near the plane of the Milky Way. The dark, cool region is dotted with stellar factories, like pearls on a cosmic string.

The spacecraft, on September 3, aimed its telescope at a reservoir of cold gas in the constellation of Southern Cross near the Galactic Plane. As the telescope scanned the sky, the spacecraft’s Spectral and Photometric Imaging Receiver (SPIR) and Photoconductor Array Camera and Spectrometer (PACS) instruments took the pictures, the European Space Agency said.

The region captured is located about 60° from the Galactic Centre, thousands of light-years from Earth.

The images reveal structure in cold material in our Galaxy, and even before a detailed analysis, scientists have gleaned information on the quantity of the material, its mass, temperature, composition and whether it is collapsing to form new stars.

That a dark, cool area such as this would be bustling with activity, was unexpected. However, the latest images reveal a surprising amount of turmoil – the interstellar material is condensing into continuous and interconnected filaments glowing from light emitted by new-born stars at various stages of development.

Stars form in cold, dense environments, and in these images, it is easy to locate the star-forming filaments that would be very difficult to isolate in a single-wavelength image.

The five original infrared wavelengths have been colour-coded to allow scientists to differentiate extremely cold material (red) from the surrounding, slightly warmer stuff (blue).

Traditionally, in a crowded region like this, which is situated in the plane of our Galaxy and contains many molecular clouds along the line of sight, astronomers have had a difficult time resolving details.

However, Herschel’s sophisticated infrared instruments have made the task easy by seeing through the dust that is opaque to visible light, and seeing the glow from the dust itself. And the result is a view of an incredible network of filamentary structures, and features indicating a chain of near-simultaneous star-formation events, glittering like strings of pearls deep in our Galaxy.