July 10, 2009

Herschel Reveals Its Incredible Potential

Europe's Herschel space observatory has had incredible results with its first test observation using three of its instruments, which proves it is on its way to becoming one of the most dynamic tools ever created to study the cosmic roots of the world as we know it.

While their set-up is not quite complete, the "first light" data demonstrates amazing ability.

The telescope first targeted galaxies, star-forming regions and dying stars. They gathered amazing data on the first try, finding water and carbon and even revealing dozens of distant galaxies.

In the galaxy images the European Space Agency released Friday, they were able to see remarkable details on objects that had never been seen before.

These observations reveal the great capacity of Herschel's instruments beyond what they ever expected.

The images shed light on star formation and galaxy evolution, providing rich material for eager astronomers. 

"We have some excellent images; they're not calibrated, but they look spectacular," said Dr Göran Pilbratt, ESA's Herschel project scientist.

"They tell you we are working; it's just fantastic," he told BBC News.

Herschel is sensitive to light at long wavelengths in the far-infrared and sub-millimeter range (55 to 672 microns).

Observations at these longer wavelengths might not produce the as ascetically appealing pictures as those obtained at shorter wavelengths, such as the visible light detected by the famous Hubble telescope, but they can see details in celestial objects unseen by Hubble. Herschel's giant 3.5-meter mirror produces extremely detail rich images.

The release on Friday included the first two galaxy observations using the European telescope, SPIRE (Spectral and Photometric Imaging Receiver).

SPIRE, the imaging camera and low-resolution spectrometer, has pictured a face-on spiral galaxy located about 24 million light-years from Earth in the constellation Pisces called M74 (also known as NGC 628), as well as a barred spiral galaxy located about 36 million light-years away in the constellation Leo called M66 (also known as NGC 3627).

Herschel is able to see more than mere stars. It is able to view the dusty clouds of gas that give rise to stars.

SPIRE is designed to observe star formation in our own Galaxy as well as in neighboring galaxies. It will also search for star-forming galaxies in the very distant Universe. Because of the great distance between the earth and these galaxies, their light has taken a very long time to reach us. Therefore, by detecting them we are in fact looking into the past do discover how and when galaxies like our own were formed.

"We're seeing the hidden life of the galaxy that never shows up in visible light images," explained Professor Matt Griffin, the principal investigator on the UK-led SPIRE consortium.

"We see the dust which is a tracer for all the gas and dust which are the raw materials from which star formation occurs. These are fairly normal galaxies where star formation is going on in a continuous cycle; and the red [freckles] you see in the images are very distant galaxies, probably undergoing intense bursts of star formation."

The Cardiff University researcher added, "This really was take off the blindfold, point and shoot, and see what we see. These were the very first observations; and there is a long way to go in terms of the way we set up the instrument, do the image processing and the map making. But it's incredible."

Also in the release are new images from Herschel's Photoconductor Array Camera and Spectrometer (PACS); and its Heterodyne Instrument for the Far Infrared.

Herschel was sent into space on May 14 along with ESA's Planck telescope.

For the past two months, both astronomical satellites have been making their way to observation positions nearly one million miles from Earth, on its "night side".

Engineers have taken advantage of the long journey by testing out all of the telescopes' systems.

This past week, a major review of the observatories' status was held in Darmstadt, Germany. The industrial manufacturers, a pan-European industrial consortium led by Thales Alenia Space, officially handed over the facilities in the meeting.

"We're now going to start to tune the instruments for maximum performance," explained Dr Pilbratt. "We're going to try them out in many different observing situations in order to learn how to get the best out of them."

A six-week demonstration phase, which the operations team hopes will reveal the full power of a perfectly prepared and matured Herschel space observatory, will follow the verification period.

Routine operations are expected to begin near the end of the year.

Herschel is set to work until 2013, when the super-fluid helium keeping its instruments and detectors in the necessary ultra-cold state for observations will have boiled off.


Image 1: M74 (also known as NGC 628) is a face-on spiral galaxy located about 24 million light years from Earth in the constellation Pisces. The infrared SPIRE images trace the cold dust between the stars, clearly showing the galaxy's spiral structure. They also contain many faint dots that are actually distant galaxies. These galaxies contain dust that radiates at infrared wavelengths, but because they are much further away, we cannot see the structure in the galaxies. Credits: ESA and the SPIRE consortium

Image 2: SPIRE images of galaxy M74 at three different infrared wavelengths. These wavelengths are the equivalent of blue, green and red colours in the visible spectrum. The images have been processed to bring out the extended structure of the galaxy and to show more detail in the background sky. The image quality is best at 250 microns because all telescopes produce their sharpest images at their shortest wavelengths. By combining the three images, astronomers can measure the properties of the emitting dust and identify the nature of the many distant galaxies that also appear in the pictures. Herschel's primary mirror is 3.5 m in diameter, nearly four times larger than any previous infrared space telescope. These images prove that it represents a giant leap forward in our ability to study celestial objects at far infrared wavelengths. Spitzer primarily observes shorter infrared wavelengths than Herschel, so the two telescopes complement each other. Credits: ESA and the SPIRE consortium


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