December 22, 2008
Taiwanese astronomers will participate in the North American component of the international Atacama Large Millimeter/submillimeter Array (ALMA) partnership, alongside American and Canadian astronomers. The National Radio Astronomy Observatory (NRAO) announced a formal agreement stating that Taiwan’s efforts will be led by the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA).

ALMA is among the most ambitious ground-based astronomical observatory in history. Currently under construction in Chile’s Atacama Desert at an altitude of 16,500 feet, it promises to revolutionize our understanding of the formation of planets, stars, and galaxies when it begins full science operations early in the next decade.

The agreement, signed by the Taipei Economic and Cultural Representative Office and the American Institute in Taiwan, provides for approximately $20 million in ALMA construction funding through the National Science Council, Taiwan’s equivalent to the United States National Science Foundation and Canada’s National Research Council, which have jointly funded North America’s existing contribution to the international ALMA project.

Activities under the agreement will include joint research projects, development projects, collaboration on construction, and support of observatory operations. Access to ALMA observing time will be shared, as will membership on advisory committees.

“Taiwan is a world-class center for submillimeter-wavelength astronomical research, and we’re delighted that the ALMA project and all its future users will benefit from the resources and expertise that Taiwan’s deepening participation brings to this great, global endeavor,” said Dr. Fred Lo, NRAO’s director.

This new agreement increases and diversifies Taiwan’s Academia Sinica investment in ALMA beyond the levels achieved through its participation in the East Asian component of the ALMA partnership, which is led by the National Astronomical Observatory of Japan.

The agreement mirrors previous ones affording Taiwan astronomers enhanced access to NRAO’s U.S.-based research facilities.

“ALMA will be one of the greatest ground-based observatories of the coming decade, and we look forward eagerly to working alongside our colleagues at the NRAO, and with the other ALMA partners, to make LAMA even more successful,” said Dr. Paul Ho, ASIAA’s director.

December 22, 2008
Researchers using a powerful instrument aboard NASA’s Mars Reconnaissance Orbiter have found a long-sought mineral on the martian surface and, with it, unexpected clues to the Red Planet’s watery past.

Surveying intact bedrock layers with the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), scientists found carbonate minerals, indicating that Mars had neutral to alkaline water when the minerals formed at these locations more than 3.6 billion years ago. Carbonates, which on Earth include limestone and chalk, dissolve quickly in acid. Therefore, their survival until today on Mars challenges suggestions that an exclusively acidic environment later dominated the planet. Instead, it indicates that different types of watery environments existed. The greater the variety of wet environments, the greater the chances one or more of them may have supported life.

“We’re excited to have finally found carbonate minerals because they provide more detail about conditions during specific periods of Mars’ history,” said Scott Murchie, principal investigator for the instrument at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

The findings will appear in the December 19 issue of Science magazine and were announced December 18 at a briefing at the American Geophysical Union’s Fall Meeting in San Francisco.

Carbonate rocks are created when water and carbon dioxide interact with calcium, iron or magnesium in volcanic rocks. Carbon dioxide from the atmosphere becomes trapped within the rocks. If all of the carbon dioxide locked in Earth’s carbonates were released, our atmosphere would be thicker than that of Venus. Some researchers believe that a thick, carbon dioxide-rich atmosphere kept ancient Mars warm and kept water liquid on its surface long enough to have carved the valley systems observed today.

“The carbonates that CRISM has observed are regional rather than global in nature, and therefore, are too limited to account for enough carbon dioxide to form a thick atmosphere,” said Bethany Ehlmann, lead author of the article and a spectrometer team member from Brown University in Providence, Rhode Island.

“Although we have not found the types of carbonate deposits which might have trapped an ancient atmosphere,” Ehlmann said, “we have found evidence that not all of Mars experienced an intense, acidic weathering environment 3.5 billion years ago, as has been proposed. We’ve found at least one region that was potentially more hospitable to life.”

The article reports clearly defined carbonate exposures in bedrock layers surrounding the 925-mile (1,490-kilometer) diameter Isidis impact basin, which formed more than 3.6 billion years ago. The best-exposed rocks occur along a trough system called Nili Fossae, which is 414 miles (670 km) long, at the edge of the basin. The region has rocks enriched in olivine, a mineral that can react with water to form carbonate.

“This discovery of carbonates in an intact rock layer, in contact with clays, is an example of how joint observations by CRISM and the telescopic cameras on the Mars Reconnaissance Orbiter are revealing details of distinct environments on Mars,” said Sue Smrekar, deputy project scientist for the orbiter at NASA’s Jet Propulsion Laboratory in Pasadena, California.

NASA’s Phoenix Mars Lander discovered carbonates in soil samples. Researchers had previously found them in Martian meteorites that fell to Earth and in windblown Mars dust observed from orbit. However, the dust and soil could be mixtures from many areas, so the carbonates’ origins have been unclear. The latest observations indicate carbonates may have formed over extended periods on early Mars. They also point to specific locations where future rovers and landers could search for possible evidence of past life.

December 22, 2008
High in the Atacama region in northern Chile, one of the world’s most advanced telescopes passed a milestone recently. The first of many state-of-the-art antennae has been handed over to the Atacama Large Millimeter/submillimeter Array (ALMA) project. ALMA is under construction on the plateau of Chajnantor, at an altitude of 3 miles (5 kilometers). The telescope is being built by a global partnership and the European Southern Observatory (ESO) represents the European partner.

ALMA will initially comprise 66 high-precision antennae, with the option to expand in the future. There will be an array of fifty 40-foot (12m) antennae, acting together as a single giant telescope, and a compact array composed of 23-foot (7m) and 40-foot (12m) diameter antennae.

ALMA will help astronomers study the cool universe – the molecular gas and tiny dust grains from which stars, planetary systems, galaxies and even life are formed. ALMA will provide new insights into the formation of stars and planets, and will reveal distant galaxies in the early universe, which we see as they were more than 10 billion years ago.

The Mitsubishi Electric Corporation built the first 40-foot (12m) diameter antenna for the National Astronomical Observatory of Japan, one of the ALMA partners. North American and European antennae will join the first antenna shortly.

“Our Japanese colleagues have produced this state-of-the-art antenna to exacting specifications. We are very excited about the handover because now we can fully equip this antenna for scientific observations,” said Thijs de Graauw, ALMA director.

Antennae arriving at the ALMA site undergo a series of tests to ensure that they meet the strict requirements of the telescope. The antennae have surfaces accurate to less than the thickness of a human hair, and can be pointed precisely enough to pick out a golf ball at a distance of 9 miles (15 km).

“ALMA is very important to European astronomers and to ESO, because it allows us to look at the universe in a way that has never been possible before. It really marks the start of a new era in astronomy,” said Wolfgang Wild, the European ALMA project manager.

The observatory team now can proceed with integrating the rest of the components, including the sensitive receivers that will collect the faint cosmic signals from space.

The antennae are tested at the Operations Support Facility, at an altitude of 1.8 miles (2.9 km), before being moved to the plateau of Chajnantor at 3 miles (5 kilometers). The Operations Support Facility will also be the observatory’s control center.

ALMA is being built on the Chajnantor plateau, high in the Chilean Andes, because the site’s extreme dryness and altitude offer excellent conditions for observing the submillimeter-wavelength signals for which the telescope is designed.

In addition, Chajnantor’s wide plateau offers ample space for the construction of the antenna array, which is spread out and linked together over distances of more than 10 miles (16 km).

“The ALMA antennae must withstand the harsh conditions at Chajnantor with strong winds, cold temperatures and a thin atmosphere with half as much oxygen as at sea level. This forbidding environment also poses challenges for the workers building ALMA,” said de Graauw.

Each antenna weighs about 100 tons and can be moved to different positions to reconfigure the ALMA telescope.

December 17, 2008
A research group led by graduate student Violette Impellizzeri from the Max Planck Institute for Radio Astronomy used the 328 foot (100m) Effelsberg radio telescope to detect water at the greatest distance from Earth so far. The water vapor was discovered in the quasar MG J0414+0534 at redshift 2.64, which corresponds to light travel time of 11.1 billion years, a time when the universe was only a fifth of the age it is today. The water vapor is thought to exist in clouds of dust and gas that feed the super-massive black hole at the center of the distant quasar. The detection was later confirmed by high-resolution interferometric observations with the Expanded Very Large Array (EVLA).

This discovery of water in the early universe was possible due to the chance alignment of a foreground galaxy and the distant quasar MG J0414+0534. The foreground galaxy acts like a cosmic telescope, magnifying and distorting the light from the quasar, and forms four distinct images of the quasar. Without this gravitational-lensing effect, 580 days of continuous observations with the 328 foot (100m) telescope would have been needed instead of the 14 hours used to make this remarkable discovery.

The Effelsberg radio telescope also detected water from MG J0414+0534. The object is within the right redshift interval to stretch the line emission of the water molecule from its original frequency of 22 GHz to 6 GHz and so within the tuning range of the 6 GHz receiver installed at the telescope.

“It is interesting that we found water in the first gravitationally magnified object we observed from the distant universe”, said co-author John McKean. “This suggests that water may be much more abundant in the early universe than first thought, and it can be used for further research into super-massive black holes and galaxy evolution at high redshift.”

The water emission was seen in the form of a maser, which is beamed radiation similar to a laser, but at microwaves. The signal corresponds to a luminosity of 10,000 times the luminosity of the Sun. Such astrophysical masers are known to originate in regions of hot and dense dust and gas. With the detection of water from MG J0414+0534, it is the first time such a dense gas cloud has been observed in the early universe, and it shows that the conditions for the water molecule to form and survive already existed only 2.5 billion years after the Big Bang.

Water masers have been found in a number of galaxies at closer distances. Typically, they are thought to arise in the hot gas and dust closely orbiting a super-massive black hole at the galaxy’s core. This amplified radio emission is more often observed when the orbiting disk is seen nearly edge-on. However, the astronomers say MG J0414+0534 is oriented with the disk almost face-on as seen from Earth. “This may mean that the water molecules in the masers we’re seeing are not in the disk, but in the super-fast jets of material being ejected by the gravitational power of the black hole,” said John McKean.

For the future, the detection of water in distant galaxies may still be challenging due to the sensitivity limitations of current-day telescopes. Of the nearby galaxies within half a billion light-years from Earth, only about one hundred galaxies show detectable water vapor emission, and almost all of them are relatively nearby. “In 2003, I was already participating in the detection of water mega-maser emission in the galaxy 3C 403,” said Christian Henkel, co-author of the study. At that time, it was the most distant galaxy where water had been detected. Later on, this record went to a galaxy with water emission at redshift 0.66, (light travel time of 6 billion years). “Now MG J0414+0534 at redshift 2.64 is by far the most distant galaxy to show water vapor emission,” he said.

“Because water masers arise close from the cores of galaxies, our result opens new interesting possibilities for studying super-massive black holes at a time when galaxies were forming,” said Violette Impellizzeri. “It will also generate further searches for water in other distant galaxies with the telescopes we have at our disposal today and with the next generation of radio telescopes; we now know water is out there.”

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