Herschel’s first glimpse into space

The Herschel Space Observatory sends back the first images to earth: the image quality is outstanding

June 19, 2009

The Herschel Space Observatory, launched only a month ago, is still being commissioned, and the first images from its instruments were planned to arrive in a few weeks. But, when the spacecraft’s cryostat cover was opened on Sunday, 14 June, and the instruments were able to "see" the sky for the first time, ESA suggested using this opportunity to produce a very early image that could give a glimpse of things to come. The Photodetector Array Camera and Spectrometer (PACS) was lucky enough to capture some images, indeed, that immediately demonstrated the superiority of Herschel, the largest infrared space telescope.

Far-infrared colour image of the "Whirlpool Galaxy" M51. Red, green and blue colours in this image correspond to the 160 microns, 100 microns and 70 microns wavelength bands of the Herschel/PACS instrument. At these wavelengths we see the glowing light from clouds of dust and gas around and between the stars. These clouds provide the reservoir of raw materials for the ongoing star formation in this galaxy. Blue colours indicate regions of warm dust that are heated by nearby young stars, while the colder dust in other parts of M51 shows up in red.

The images show the famous ‘whirlpool galaxy’, first observed by Charles Messier in 1773 who provided the designation Messier 51 (M51). This classic example of a spiral galaxy lies relatively nearby, about 37 million light-years away, in the constellation of Canes Venatici.

The images were taken with the 3-band photometer of PACS, at wavelengths of 160 microns, 100 microns, and 70 microns. These wavelengths are about 200 times longer than those of the light we see with our eyes! The new, large telescope of Herschel allows us - for the first time - to capture sharp images in this very special light, which is ideally suited to discover and investigate regions where stars are being formed and to peer into the obscured cores of galaxies, which, like M51, often contain super-massive black holes.

Side-by-side comparison of an M51 image taken with the Spitzer Space Observatory and the same image taken with the recently launched Herschel Space Observatory. The obvious advantage of the larger size of the telescope is clearly reflected in the much higher resolution of the image: Herschel reveals structures that cannot be discerned in the Spitzer image. Both images were taken at a wavelength of 160 microns.

These images, produced from the very first test observation, lead scientists to conclude that the optical performance of Herschel and its large telescope is so far meeting their high expectations.

Acknowledgements / Credits

PACS has been designed and built by a consortium of institutes and university departments from across Europe under the leadership of Principal Investigator Albrecht Poglitsch located at the Max-Planck-Institute for Extraterrestrial Physics in Garching, Germany. Consortium members are: Austria: UVIE; Belgium: IMEC, KUL, CSL; France: CEA, OAMP; Germany: MPE, MPIA; Italy: IFSI, OAP/AOT, OAA/CAISMI, LENS, SISSA; Spain: IAC; Hungary: Konkoly; USA: NHSC

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