The Einstein Telescope (Underground Observatory)

By Astroparticle European Research Area Press Office, Geneva, Switzerland
Published: May 19, 2011

A new era in astronomy will come a step closer when scientists from across Europe present their design study today, May 19, for an advanced observatory capable of making precision measurements of gravitational waves — minute ripples in the fabric of space-time — predicted to emanate from cosmic catastrophes such as merging black holes and collapsing stars and supernovae. It also offers the potential to probe the earliest moments of the universe just after the Big Bang, which is currently inaccessible.

The Einstein Observatory (ET) is a third-generation gravitational-wave (GW) detector, which will be 100 times more sensitive than current instruments. Like the first two generations of GW detectors, it is based on the measurement of tiny changes (far less than the size of an atomic nucleus) in the lengths of two connected arms several kilometers long, caused by a passing gravity wave. Laser beams passing down the arms record their periodic stretching and shrinking as interference patterns in a central photo-detector.

The first generation of these interferometric detectors built a few years ago (GEO600, LIGO, Virgo, and TAMA) successfully demonstrated the proof-of-principle and constrained the gravitational wave emission from several sources. The next generation (Advanced LIGO and Advanced Virgo), which is being constructed now, should make the first direct detection of gravitational waves — for example, from a pair of orbiting black holes or neutron stars spiraling into each other. Such a discovery would herald the new field of GW astronomy. However, these detectors will not be sensitive enough for precise astronomical studies of the GW sources.

"The community of scientists interested in exploring GW phenomena, therefore, decided to investigate building a new generation of even more-sensitive observatories. After a three-year study involving more than 200 scientists in Europe and across the world, we are pleased to present the design study for the Einstein Telescope, which paves the way for unveiling a hidden side of the universe," said Harald Lück, deputy scientific coordinator of the ET Design Study.

The design study outlines ET’s scientific targets, the detector layout and technology, as well as the timescale and estimated costs. A superb sensitivity will be achieved by building ET underground at a depth of about 330 feet to 660 feet (100 to 200 meters) to reduce the effect of residual seismic motion. This will enable higher sensitivities to be achieved at low frequencies, between 1 and 100 hertz (Hz). With ET, the entire range of GW frequencies that can be measured on Earth — between about 1 Hz and 10 kHz — should be detected. “An observatory achieving that level of sensitivity will turn GW detection into a routine astronomical tool. ET will lead a scientific revolution,” said Michele Punturo, scientific coordinator of the design study. An important aim is to provide GW information that complements observational data from telescopes detecting electromagnetic radiation (from radio waves through to gamma-rays) and other instruments detecting high-energy particles from space (astroparticle physics).

The strategy behind the ET project is to build an observatory that overcomes the limitations of current detector sites by hosting more than one GW detector. It will consist of three nested detectors, each composed of two interferometers with arms 6 miles (10 kilometers) long. One interferometer will detect low-frequency gravitational wave signals (2 to 40 Hz) while the other will detect the high-frequency components. The configuration is designed to allow the observatory to evolve by accommodating successive upgrades or replacement components that can take advantage of future developments in interferometry and also respond to a variety of science objectives.

The European Commission supported the design study within the Seventh Framework Program (FP7-Capacities) by allocating three million Euros. “With this grant, the European Commission recognized the importance of gravitational wave science as developed in Europe, its value for fundamental and technological research, provided a common framework for the European scientists involved in the gravitational wave search, and allowed for a significant step towards the exploration of the universe with a completely new inquiry instrument,” said Federico Ferrini from the European Gravitational Observatory.

ET is one of the “Magnificent Seven” European projects recommended by the ASPERA network for the future development of astroparticle physics in Europe. It would be a crucial European research infrastructure and a fundamental cornerstone in the realization of the European Research Area.

The Square Kilometer Array: world’s biggest telescope

Artist's impression of the SKA dishes.(courtesy: University of Manchester)
By the Science and Technology Facilities Council, United Kingdom —
Published: April 4, 2011

Plans for the world’s biggest telescope — the Square Kilometer Array (SKA) — advanced significantly April 2, with a decision to locate the project office at Jodrell Bank Observatory near Manchester, support from the partners including the United Kingdom for the next phase of the project, and the first steps toward creating the legal entity needed to deliver this ambitious global project.

The SKA is a $2.1 billion multinational science project to build the world’s largest and most sensitive radio telescope. The SKA will be capable of answering some of the most fundamental questions about the universe, including helping to understand dark energy, general relativity in extreme conditions, and how the universe came to the look the way it does now.

The SKA will be an array of radio antennas with a collection area of a square mile with its core in South Africa or Australia. Signals from individual antennas will be combined to form one giant telescope. In the same way, the famous Lovell Telescope at the University of Manchester’s Jodrell Bank Observatory is used with other United Kingdom telescopes (the e-MERLIN network) and as part of an international network. With an antenna at Chilbolton, the United Kingdom is also part of LOFAR, a low-frequency network centered in the Netherlands. SKA builds on this technique and tradition of collaboration, bringing together all the major groups in radio astronomy.

“Since the 1950s, radio astronomy has provided scientific pioneers with tools to revolutionize our understanding of the universe,” said Jocelyn Bell Burnell from the Institute of Physics. “The power of this new telescope project, however, is going to surpass anything we’ve seen before, enabling us to see many more radio-emitting stars and galaxies and pulling the curtains wide open on parts of the great beyond that radio astronomers like me have only dreamed of exploring. The SKA heralds in a post-Einstein era of physics that will help us take huge strides in our attempt to understand the most bizarre objects and the darkest ages of the universe.”
United Kingdom home to the SKA project office Minister for Universities and Science, David Willetts said: “The Square Kilometer Array is a project of global significance. This is evidence of the high reputation of Britain’s management of international science projects. It is great news for Britain and for Jodrell Bank, and Manchester University in particular.”

“It is great to see such significant progress being made towards building the SKA, one of our highest priorities in astronomy,” said John Womersley from the Science and Technology Facilities Council. “The universities of Cambridge, Oxford, and Manchester have a great heritage in astronomy, and they are working together in SKA to ensure the United Kingdom takes a leading role in this exciting global project to better understand the universe we live in.”

“Jodrell Bank is an ideal place for scientists and engineers to work together to plan the world’s largest radio telescope alongside world-leading radio astronomy facilities and the new Discovery Center,” said Stephen Watts from the University of Manchester. “Together, these offer a real opportunity to inspire people of all ages with this ambitious project to answer truly fundamental questions about the nature of the universe.” “The move to Jodrell Bank comes at a crucial time as the project grows from a concept to an international mega science project,” said Richard Schilizzi from the SKA. “The new location and facilities will support the significant expansion that is planned.”

Agreeing to an international partnership The SKA has been agreed as a top priority project for astronomy both in the United Kingdom and across Europe. It is a significant step that nine partners have started the process to secure funding and create a legal structure for the SKA. The United Kingdom, through the Science and Technology Facilities Council, is expecting to invest about $24 million in the next phase of the SKA.

In addition to the immense scientific progress that will be made by the SKA, the project is expected to have wider benefits in continuing its already impressive involvement with industrial partners and continuing the inspiration of the public through astronomy.

The SKA project will drive technology development in antennas, signal transport, signal processing, software, and computing. Spin- off innovations in these areas will benefit other systems that process large volumes of data. The design, construction, and operation of the SKA has the potential to impact skills development in science, engineering, and in associated industries not only in the host countries, but also in all project partners.

APEX reveals glowing stellar nurseries

Glowing stellar nurseries.
ESO PR Photo 40/08
Credit: ESO/APEX/DSS2/SuperCosmos

Illustrating the power of submillimetre-wavelength astronomy, an APEX image reveals how an expanding bubble of ionised gas about ten light-years across is causing the surrounding material to collapse into dense clumps that are the birthplaces of new stars. Submillimetre light is the key to revealing some of the coldest material in the Universe, such as these cold, dense clouds.

The region, called RCW120, is about 4200 light years from Earth, towards the constellation of Scorpius. A hot, massive star in its centre is emitting huge amounts of ultraviolet radiation, which ionises the surrounding gas, stripping the electrons from hydrogen atoms and producing the characteristic red glow of so-called H-alpha emission.

As this ionised region expands into space, the associated shock wave sweeps up a layer of the surrounding cold interstellar gas and cosmic dust. This layer becomes unstable and collapses under its own gravity into dense clumps, forming cold, dense clouds of hydrogen where new stars are born. However, as the clouds are still very cold, with temperatures of around -250˚ Celsius, their faint heat glow can only be seen at submillimetre wavelengths. Submillimetre light is therefore vital in studying the earliest stages of the birth and life of stars.

The submillimetre-wavelength data were taken with the LABOCA camera on the 12-m Atacama Pathfinder Experiment (APEX) telescope, located on the 5000 m high plateau of Chajnantor in the Chilean Atacama desert. Thanks to LABOCA's high sensitivity, astronomers were able to detect clumps of cold gas four times fainter than previously possible. Since the brightness of the clumps is a measure of their mass, this also means that astronomers can now study the formation of less massive stars than they could before.

The plateau of Chajnantor is also where ESO, together with international partners, is building a next generation submillimetre telescope, ALMA, the Atacama Large Millimeter/submillimeter Array. ALMA will use over sixty 12-m antennas, linked together over distances of more than 16 km, to form a single, giant telescope.

APEX is a collaboration between the Max-Planck-Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. The telescope is based on a prototype antenna constructed for the ALMA project. Operation of APEX at Chajnantor is entrusted to ESO.

'Ghost of Mirach' Materializes in Space Telescope Image

Credit: NASA/JPL-Caltech/DSS

NASA's Galaxy Evolution Explorer has lifted the veil off a ghost known to haunt the local universe, providing new insight into the formation and evolution of galaxies.

The eerie creature, called NGC 404, is a type of galaxy known as "lenticular." Lenticular galaxies are disk-shaped, with little ongoing star formation and no spiral arms. NGC 404 is the nearest example of a lenticular galaxy, and therefore of great interest. But it lies hidden in the glare from a red giant star called Mirach. For this reason, NGC 404 became known to astronomers as the "Ghost of Mirach."

When the Galaxy Evolution Explorer spied the galaxy in ultraviolet light, a spooky ring materialized.

"We thought this celestial ghost was essentially dead, but we've been able to show that it has an extended ring of new stars. The galaxy has a hybrid character in which the well-known, very old stellar population tells only part of the story," said David Thilker of Johns Hopkins University in Baltimore. "It's like the living dead."

Thilker and members of the Galaxy Evolution Explorer team spotted the Ghost of Mirach in images taken during the space telescope's all-sky survey. The Galaxy Evolution Explorer is a relatively low-cost NASA mission, launched in 2003, with an ambitious charge to survey the entire visible sky in ultraviolet light, a job never before accomplished. Because Earth's atmosphere absorbs ultraviolet photons -- a good thing for us living creatures who are susceptible to the damaging light -- ultraviolet telescopes must operate from space.

The first images of the Ghost of Mirach taken by the Galaxy Evolution Explorer hinted at a surrounding ultraviolet-bright extended structure. Subsequent, longer exposure observations indeed show that the lenticular galaxy is surrounded by a clumpy, never-before-seen ring of stars.

What is this mysterious ultraviolet ring doing around an otherwise nondescript lenticular galaxy? As it turns out, previous imaging with the National Science Foundation's Very Large Array radio telescope in New Mexico had discovered a gaseous ring of hydrogen that matches the ultraviolet ring observed by the Galaxy Evolution Explorer. The authors of this Very Large Array study attributed the gas ring to a violent collision between NGC 404 and a small neighboring galaxy 900 million years ago.

The ultraviolet observations demonstrate that, when the hydrogen from the collision settled into the plane of the lenticular galaxy, stars began to form in a ghostly ring. Young, relatively hot stars forming in stellar clusters sprinkled throughout NGC 404's ring give off the ultraviolet light that the Galaxy Evolution Explorer was able to see.

"Before the Galaxy Evolution Explorer image, NGC 404 was thought to contain only very old and evolved red stars distributed in a smooth elliptical shape, suggesting a galaxy well into its old age and no longer evolving significantly," said Mark Seibert of the Observatories of the Carnegie Institution of Washington in Pasadena, Calif. "Now we see it has come back to life, to grow once again."

"The Ghost of Mirach has been lucky enough to get a new lease on life through the rejuvenating, chance merger with its dwarf companion," added Thilker.

The findings indicate that the evolution of lenticular galaxies might not yet be complete. They may, in fact, continue to form stars in a slow, piecemeal fashion as they suck the raw, gaseous material for stars from small, neighboring galaxies. It seems the Ghost of Mirach might act more like a vampire than a ghost.

Caltech leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the mission and built the science instrument. The mission was developed under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on this mission.