Herschel Space Observatory Captures the Birth of Stars

The European Space Agency has released a preview of the first science results from the Herschel Space Observatory, including the UK-led SPIRE instrument. The new data which include images of previously invisible stardust — the stuff that all life is made from — will give us valuable new information about how stars and galaxies are made and reveal the life cycle of the cosmos.

Professor Keith Mason, Chief Executive of the Science and Technology Facilities Council (STFC), which provides the UK funding for Herschel, said, “These results are extremely impressive and are an indication of the excellent science that Herschel, including SPIRE, will perform over the next few years. We’re very proud of the technology and expertise that the UK has contributed to this groundbreaking mission.”

Professor Matt Griffin, SPIRE Principle Investigator, said, “The Herschel Science Demonstration meeting is what the SPIRE team has been looking forward to since the start of the project more than a decade ago, and the results being presented are even better than we dared hope before launch. Not only are the observatory and the instrument working very well, but it is already clear that in this unexplored region of the spectrum, the Universe is even more interesting than we thought.”

Figure 1 shows a three-color composite of a region of star formation in the constellation of Aquila around 1000 light-years from Earth. In the image, the red shows light at 500 microns detected by SPIRE, while green and blue are light at 170 microns and 70 microns respectively, as measured by PACS. [1 micron, or micrometer, is 0.001 mm.] The size of the area imaged is around 60 light-years per side, and shows the large filaments of cold dust (seen as red and orange) threading through the region. The many blue regions are warmer, emitting more at shorter wavelengths, and show where the gas and dust is either collapsing under gravity to form stars, or where it has already collapsed and formed a protostar (the earliest stages of a star’s life). Professor Derek Ward-Thompson, of Cardiff University and a member of the Gould Belt Key Project, for which this image was taken, said, “The insight into the way stars are forming that is provided by this image is absolutely fantastic, and I can’t wait to see the rest of the data we’re going to receive over the coming months.” There are hundreds such regions found in the image, and this confirms the connection between the large, cool filaments and the locations where stars form.

Figure 2 shows a region of the Virgo cluster, a large cluster of galaxies around 50 million light-years from our galaxy. The left panel shows a region containing four galaxies in optical light, from the Sloan Digital Sky Survey, while the right panel shows the region as seen by SPIRE at 250 microns. The galaxies in the Virgo cluster are kept together by their mutual gravitational attraction. However, the galaxies do move relative to each other, and when they pass close to each other they can pull gas and dust into clumps and streams which stretch between the galaxies. Dr. Jonathan Davies, of Cardiff University, and Principal Investigator of the Herschel Virgo Cluster Survey, for which this image was taken, commented that “Far-infrared observations such as this give us an unprecedented insight into the behavior of gas and dust in galaxy clusters, and further observations should yield some very exciting results.” The area of emission above the galaxy NGC 4435 is very faint as seen in optical light, but much brighter in the far-infrared as measured by SPIRE. Also notable from this region is the relative brightness of the galaxies NGC 4406 and NGC 4402. NGC 4406 is a giant elliptical galaxy, and so very bright in the optical, but is almost invisible in the far-infrared. This shows that it has already used up the majority of its gas and dust in forming the stars.

Figure 3 shows an area of sky called the “Great Observatory Origins Deep Survey” (GOODS), which has been observed by many telescopes at a range of wavelengths, and now by SPIRE in the far-infrared. It is an area of sky devoid of foreground objects, such as stars within our Galaxy, or any other nearby galaxies, and is a little larger than the area of the full moon as observed from Earth. The image is made from the three SPIRE bands, with red, green and blue corresponding to 500 microns, 350 microns and 250 microns, respectively. Every fuzzy blob in this image is a very distant galaxy, seen as they were 3-10 billion years ago when the star formation was very widely spread throughout the Universe. Dr. Seb Oliver, of University of Sussex and PI of the HERMES survey for which this image was taken, said, “Seeing such stunning images after just 14 hours of observations gives us high expectations for the full length observations over much larger regions of the Universe. This will give us a much clearer idea of how star formation has progressed throughout the history of the Universe.” The redder objects are either more distant, as the expansion of the Universe has stretched the light more since it was emitted by the galaxy, or much cooler than the bluer galaxies. This is the first time much of the Cosmic Infrared Background, discovered in the 1990s, has been resolved into the individual galaxies. Studying these galaxies at this early stage of the Universe will allow astronomers to test their models of star and galaxy formation.

Professor Michael Rowan-Robinson from Imperial College London, said, “Our pre-launch models of the submillimeter sky suggest most of these galaxies will be at high redshift, so are galaxies undergoing their main bursts of star formation. The challenge will be to disentangle the effects of the cosmological redshift from the natural tendency of cooler dust in the outer parts of galaxies to be prominent at submillimeter wavelengths.”

Figure 4 shows the detection of a previously known dwarf planet, MakeMake, which orbits the Sun out beyond Neptune. MakeMake is the third largest dwarf planet known, with a diameter of around 1500 km. It is currently nearly 8 billion km from the Sun and is one of a number “Trans-Neptunian Objects”. With a surface temperature of around 30 Kelvin (-240 degrees C), Makemake is one of the coldest objects in the Solar System, and so very hard to detect. By taking images 44 hours apart and subtracting the “before” image from the “after” image, the background sky is removed. Makemake, having moved in the intervening time, appears twice in the resulting image: once as a “negative image” and again as a “positive image”. Dr. Tanya Lim, of STFC Rutherford Appleton Laboratory, and member of the project surveying the Trans-Neptunian region, said, “The detection of MakeMake with the first trial of this technique shows great promise for the future. MakeMake is found to be much fainter at submillimeter wavelengths than our predictions, indicating that the object is much more complex than we expected. With the ability of SPIRE to detect these fainter objects we can now look forward to discovering many more and deriving more accurate models of their composition.”

Further results are being presented at the Science Demonstration Phase First Result meeting in Madrid.

Notes for Editors

Since launch on 14th May 2009, Herschel spent several months undergoing careful tests on the performance of the instruments and calibration. This was followed by the Science Demonstration Phase: the period when the instruments were tested to their full capabilities.

To date, the mission has gone almost perfectly. The performance of the spacecraft has been shown to be well within pre-launch expectations, and the SPIRE and PACS instruments are working extremely reliably and the first look at the data is exceedingly promising. A problem with the HIFI instrument in August 2009 led to it being turned off for several months while further checks were carried out. Earlier this month HIFI was powered up again for the first time since the problem occurred, using its backup power supply unit. HIFI should be fully operational from January, giving Herschel back its full complement of scientific instruments. The science demonstration will continue in early 2010, while in the meantime routine scientific observations can begin.

In November 2009 Time Magazine voted Herschel the 7th best invention of 2009, ranking just above an AIDS vaccine and a chip which could give blind people partial eyesight.

Images

Fig 1:
http://www.scitech.ac.uk/resources/image/jpg/aquila.jpg

Fig 2:
http://www.scitech.ac.uk/resources/image/jpg/virgo.jpg

Fig 3:
http://www.scitech.ac.uk/resources/image/jpg/goods.jpg

Fig 4:
http://www.scitech.ac.uk/resources/image/jpg/makemake.jpg

Images of Herschel are available from the STFC Press Office

Further details of the new data from Herschel can be found at: http://herschel.esac.esa.int/

UK Herschel site: http://herschel.cf.ac.uk/

Herschel and SPIRE

The European Space Agency’s Herschel satellite carries the largest telescope to be flown in space and is designed to study the Universe at far infrared wavelengths. It will reveal the early stages of star birth and galaxy formation; it will examine the composition and chemistry of comets and planetary atmospheres in the Solar System; and it will examine the star-dust ejected by dying stars into interstellar space which form the raw material for planets like the Earth.

The SPIRE instrument has been built by a consortium of 18 institutes in eight countries (UK, France, Italy, Spain, Sweden, USA, Canada and China), led by Prof. Matt Griffin of Cardiff University. The instrument was assembled at the STFC’s Rutherford Appleton Laboratory in the UK.

Herschel Mission Timeline

* Herschel was launched on an Ariane 5 from Europe’s Spaceport in Kourou, French Guiana, on 14 May 2009.

* Commissioning Phase: In the first few days after launch basic spacecraft checks were done. About a week after launch, the Herschel scientific instruments were switched on for the first time and detailed commissioning of the instruments began.

* Performance Verification Phase: This began 60 days after launch, and is now nearing completion It has involved tests to ensure that the instrument operational modes and scientific data processing software are thoroughly checked and optimized.

* Science Demonstration Phase: Comprehensive trial scientific observations have already begun, involving execution of a selection of different kinds of observations and processing the data to produce scientific results. These will be presented at the Herschel Science Demonstration Workshop, in Madrid, on December 17 and 18.

* Routine Operations Phase: Routine operations will begin before the end of 2009, and will last for at least three years. The observational programs for the first 18 months have already been selected.

Contacts:

Julia Short
Press Officer, STFC
+44 (0)1793 442 012
Julia.short@stfc.ac.uk

Mr. Chris North
UK Herschel Outreach Officer
Cardiff University
+44 (0)29 208 70537 or 76403
chris.north@astro.cf.ac.uk

Prof. Matt Griffin
Herschel-SPIRE Principal Investigator
Cardiff University
+44 (0)29 2087 4203
matt.griffin@astro.cf.ac.uk

UK Participation in Herschel

The UK contribution to Herschel includes leadership of the international consortium that designed and built the SPIRE instrument. The UK SPIRE team is also responsible for the development of software for instrument control and processing of the scientific data, and leads the in-flight testing and operation of SPIRE. The Herschel program in the UK is funded by the Science and Technology Facilities Council.

SPIRE comprises a three band imaging photometer and an imaging Fourier transform spectrometer and has been designed and built by a consortium of institutes including a number from the UK (Cardiff University; Imperial College, London; University College London’s Mullard Space Science Laboratory; the University of Sussex; and STFC’s Rutherford Appleton Laboratory and UK Astronomy Technology Centre). The UK is also leading the development of software for controlling the instrument from the ground and processing the data to produce scientific results. The SPIRE Operations Centre, responsible for delivering all instrument software to ESA, and for day-to-day instrument monitoring, operation, and calibration, is located at the Rutherford Appleton Laboratory with contributions from the Imperial College and Cardiff groups. The UK SPIRE institutes, together with astronomers in many other UK universities, are also strongly involved in the Herschel scientific programs which have already been selected for the first 18 months of Herschel observations, and cover a wide range of science topics from our own solar system to the most distant galaxies.

Science and Technology Facilities Council (STFC)

The Science and Technology Facilities Council ensures the UK retains its leading place on the world stage by delivering world-class science; accessing and hosting international facilities; developing innovative technologies; and increasing the socio-economic impact of its research through effective knowledge exchange.

The Council has a broad science portfolio including Astronomy, Particle Physics, Particle Astrophysics, Nuclear Physics, Space Science, Synchrotron Radiation, Neutron Sources and High Power Lasers. In addition the Council manages and operates three internationally renowned laboratories:

* The Rutherford Appleton Laboratory, Oxfordshire
* The Daresbury Laboratory, Cheshire
* The UK Astronomy Technology Centre, Edinburgh

The Council gives researchers access to world-class facilities and funds the UK membership of international bodies such as the European Laboratory for Particle Physics (CERN), the Institute Laue Langevin (ILL), European Synchrotron Radiation Facility (ESRF), the European organization for Astronomical Research in the Southern Hemisphere (ESO) and the European Space Agency (ESA). It also funds UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, and the MERLIN/VLBI National Facility, which includes the Lovell Telescope at Jodrell Bank Observatory. The Council distributes public money from the Government to support scientific research.

The Council is a partner in the UK space program, coordinated by the British National Space Centre.