Telescope Camera Debuts With Peek At Nest Of Black Holes

Less than two months after they inaugurated the world’s largest telescope, University of Florida astronomers have used one of the world’s most advanced telescopic instruments to gather images of the heavens.

A team led by astronomy professor Stephen Eikenberry late last week captured the first images of the cosmos ever made with a UF-designed and built camera/spectrometer affixed to the Gemini South telescope in Chile. The handful of “first light” images include a yellow and blue orb-like structure that depicts our Milky Way galaxy, home to thousands of black holes – including, at its core, a “supermassive” black hole thought to be as massive as 4 million suns put together.

“We plan to use this instrument to provide the first accurate tracking of the growth and evolution of this black hole over the last 4 billion years,” Eikenberry says.

Installation of the instrument, called FLAMINGOS-2, caps a seven-year, $5 million effort involving 30 UF scientists, engineers, students and staff. Once the instrument is scientifically tested — a process expected to last around six months — it will support a range of new science. Astronomers will use FLAMINGOS-2 (FLAMINGOS is short for the Florida Array Multi-object Imaging Grism Spectrometer) to hunt the universe’s first galaxies, view stars as they are being born, reveal black holes and investigate other phenomena.

“Achieving first light is a great achievement and important milestone,” says Nancy Levenson, deputy director of the Gemini Observatory.

The 8-meter Gemini South telescope in the Chilean Andes is one of only about a dozen 8- to 10-meter telescopes worldwide. All require technologically sophisticated instruments to interpret the light they gather. FLAMINGOS-2 “sees” near-infrared or heat-generated light beyond the range of human vision. It can reveal objects invisible to the eye, such as stars obscured by cosmic dust, or objects so far away they have next to no visible light.

The instrument joins other near-infrared imagers installed on other large telescopes. But it is unusual in its ability to also act as a spectrometer, dividing the light into its component wavelengths. Astronomers analyze these wavelengths to figure out what distant objects are made of, how hot or cold they are, their distance from Earth, and other qualities.

Uniquely, FLAMINGOS-2 can take spectra of up to 80 different objects simultaneously, speeding astronomers’ hunt for old galaxies, black holes or newly forming stars and planets.

“At a cost of $1 per second for operating the Gemini telescope, it will make a huge gain in the scientific productivity and efficiency of the observatory,” Eikenberry says. “What would take an entire year previously can now be done in four nights. This is a real game changer.”

Astronomers compete heavily for time on the world’s largest telescopes, often waiting months or years for the opportunity to make observations. Eikenberry said his FLAMINGOS-2 agreement with Gemini South entitles him to at least 25 nights of observations. He will use the time to contribute to three large studies, or surveys, of the sky headed by UF astronomers.

The first is aimed at learning more about the thousands of black holes and neutron stars at the Milky Way’s center. The second will probe the formation and evolution of galaxies across time, while the third will investigate the birth of new stars.

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Video of the Day: The Search for Killer Asteroids

Bay Area astronomers police the skies for earth killing asteroids.

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1st North American Antenna Enables ALMA Observatory to Do Its Thing

Astronomers today celebrated the formal acceptance of the first North American antenna by the Joint ALMA Observatory. ALMA, the Atacama Large Millimeter/submillimeter Array, is a gathering armada of short-wavelength radio telescopes whose combined power will enable astronomers to probe with unprecedented sharpness phenomena and regions that are beyond the reach of visible-light telescopes. The observatory is being assembled high in the Chilean Andes by a global partnership.

With ALMA, astronomers will study the 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 will see as they were over 10 billion years ago.

The 12-meter-diameter antenna delivered today is the first of 25 being provided by North America's ALMA partners, whose efforts are led by the National Radio Astronomy Observatory and supported by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada and the National Science Council of Taiwan. The antenna was manufactured by General Dynamics SATCOM Technologies.

The acceptance comes just weeks after the first ALMA antenna--produced under the direction of the National Astronomical Observatory of Japan on behalf of ALMA's East Asian partners--was handed over to the observatory.

"These ALMA antennas are technological marvels," says ALMA Director Thijs de Graauw. "They are more precise and more capable than any ever made. Their performance in the harsh winds and temperatures of our high-altitude site bodes well for the observatory's future."

A single 12-meter antenna's dish is bigger than the largest optical telescope's reflective mirror, but to match the sharpness achieved by an optical telescope, a millimeter-wavelength dish would have to be impossibly large, miles across. ALMA will combine signals from dozens of antennas spread across miles of desert to synthesize the effective sharpness of such a single, gigantic antenna. The process, called "interferometry," involves analysis of the ways in which the signals coming from each antenna interfere with one another.

"This is a major milestone for the ALMA project," says Philip Puxley, NSF's ALMA program manager. "With two antennas now on site, we begin the real work of combining signals from them. We are advancing toward ALMA's ultimate goal of surpassing by tenfold existing technology in this area for sharper resolution, sensitivity and image quality."

ALMA officials expect the pace of antenna acceptance to accelerate. "We have nine North American antennas on site already," said Adrian Russell, NRAO's ALMA project director. "Following handover of Number Three, we plan to get one through the test procedure each month. Additional North American antennas will be arriving in Chile at a rate of one every two months, and General Dynamics is on track to complete delivery of these systems within days of the original schedule."

The antennas, which each weigh about 100 tons, can be moved to different positions in order to reconfigure the ALMA telescope. This repositioning will be carried out by two custom-designed transporters, each of which is some 33 feet wide, 66 feet long, and has 28 wheels.

When completed early this decade, ALMA will have a total of 66 antennas, with an option for further expansion, provided by partners in North America, Europe and East Asia. The first European antennas, produced under the auspices of the European Organization for Astronomical Research in the Southern Hemisphere are scheduled to begin arriving early this year.

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Worlds In Collision

Two terrestrial planets orbiting a mature sun-like star some 300 light-years from Earth recently suffered a violent collision, astronomers at UCLA, Tennessee State University (TSU) and the California Institute of Technology will report in a December issue of the Astrophysical Journal.

"It's as if Earth and Venus collided with each other," says Benjamin Zuckerman, UCLA professor of physics and astronomy and a co-author on the paper. "Astronomers have never seen anything like this before. Apparently, major catastrophic collisions can take place in a fully mature planetary system."

"If any life was present on either planet, the massive collision would have wiped out everything in a matter of minutes — the ultimate extinction event," says co-author Gregory Henry, an astronomer at TSU. "A massive disk of infrared-emitting dust circling the star provides silent testimony to this sad fate."

Zuckerman, Henry and Michael Muno, an astronomer at Caltech at the time of the research, were studying a star known as BD+20 307, which is surrounded by a shocking 1 million times more dust than is orbiting our sun. The star is located in the constellation Aries. The astronomers gathered X-ray data using the orbiting Chandra X-ray Observatory and brightness data from one of TSU's automated telescopes in southern Arizona, hoping to measure the age of the star.

"We expected to find that BD+20 307 was relatively young, a few hundred million years old at most, with the massive dust ring signaling the final stages in the formation of the star's planetary system," Muno says.

Those expectations were shown to be premature, however, when Carnegie Institution of Washington astronomer Alycia Weinberger announced in the May 20, issue of the Astrophysical Journal that BD+20 307 is actually a close binary star — two stars orbiting around their common center of mass.

"That discovery radically revised the interpretation of the data and transformed the star into a unique and intriguing system," says TSU astronomer Francis Fekel who, along with TSU's Michael Williamson, was asked to provide additional spectroscopic data from another TSU automated telescope in Arizona to assist in comprehending this exceptional binary system.

The new spectroscopic data confirmed that BD+20 307 is composed of two stars, both very similar in mass, temperature and size to our own sun. They orbit about their common center of mass every 3.42 days.

"The patterns of element abundances in the stars show that they are much older than a few hundred million years, as originally thought," Fekel says. "Instead, the binary system appears to have an age of several billion years, comparable to our solar system."

"The planetary collision in BD+20 307 was not observed directly but rather was inferred from the extraordinary quantity of dust particles that orbit the binary pair at about the same distance as Earth and Venus are from our sun," Henry says. "If this dust does indeed point to the presence of terrestrial planets, then this represents the first known example of planets of any mass in orbit around a close binary star."

Zuckerman and colleagues first reported in the journal Nature in July 2005 that BD+20 307, then still thought to be a single star, was surrounded by more warm orbiting dust than any other sun-like star known to astronomers. The dust is orbiting the binary system very closely, where Earth-like planets are most likely to be and where dust typically cannot survive long. Small dust particles get pushed away by stellar radiation, while larger pieces get reduced to dust in collisions within the disk and are then whisked away. Thus, the dust-forming collision near BD+20 307 must have taken place rather recently, probably within the past few hundred thousand years and perhaps much more recently, the astronomers said.

"This poses two very interesting questions," Fekel says. "How do planetary orbits become destabilized in such an old, mature system, and could such a collision happen in our own solar system?"

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Galaxy Zoo -- An Internet Superstar

Since Galaxy Zoo's launch in July 2007, some 150,000 members of the public, inspired by the opportunity to be the first to see and classify a galaxy, have helped professional astronomers via this online mass-participation project to carry out real scientific research.

Two of Galaxy Zoo's founders, Chris Lintott, from the Department of Physics at the University of Oxford, and Kate Land reflect on the project's success in September's Physics World.

While there has been a range of computer programs that make use of the idle time of users' PCs to churn through scientific data, like ClimatePrediction.net for modelling global warming, Galaxy Zoo was the first of its kind to engage computer users and ask them to apply their own brain power to help sort one type of galaxy from another.

With almost a million galaxy images provided by the robotic Sloan Digital Sky Survey telescope in New Mexico, the Galaxy Zoo team knew it was a tall order. However, even on the day of launch after a small news item on Radio 4's Today programme, the site was receiving more than 70,000 classifications each hour.

As Lintott and Land write, "An attractive feature of the project was that these galaxies had literally never been looked at before with the human eye – so people really felt that they were helping with original and unique contributions."

The original impetus for the project was a research dilemma that required a complete reassessment of 50,000 images. Existing criteria used to define elliptical galaxies – colour, density profile and spectral features – appeared to leave out a small fraction of important elliptical galaxies that were undergoing star formation.

The 150,000 amateur astronomers have helped make more than 50 million classifications, thereby helping the researchers obtain a good statistical error for each one. For about a third of the 900,000 galaxies, more than 80 per cent agreed on the morphology which gave the researchers an astoundingly good starting point.

Advances in our understanding of the universe have already been made and a selection of journal articles has already been published. The researchers are now developing Galaxy Zoo to make a more detailed classification of a smaller set of galaxies plus a deliberate search for more unusual objects.

The founders write, "As we develop the citizen science that powers Galaxy Zoo, we can expect many new discoveries to follow. After all, having 150,000 co-authors is an excellent motivator when it comes to writing papers."

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'Plutoid' Chosen Name For Solar System Objects Like Pluto

The International Astronomical Union has decided on the term plutoid as a name for dwarf planets like Pluto at a meeting of its Executive Committee in Oslo.

Almost two years after the International Astronomical Union (IAU) General Assembly introduced the category of dwarf planets, the IAU, as promised, has decided on a name for transneptunian dwarf planets similar to Pluto. The name plutoid was proposed by the members of the IAU Committee on Small Body Nomenclature (CSBN), accepted by the Board of Division III, by the IAU Working Group for Planetary System Nomenclature (WGPSN) and approved by the IAU Executive Committee at its recent meeting in Oslo, Norway.

Plutoids are celestial bodies in orbit around the Sun at a distance greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighbourhood around their orbit. The two known and named plutoids are Pluto and Eris. It is expected that more plutoids will be named as science progresses and new discoveries are made.

The dwarf planet Ceres is not a plutoid as it is located in the asteroid belt between Mars and Jupiter. Current scientific knowledge lends credence to the belief that Ceres is the only object of its kind. Therefore, a separate category of Ceres-like dwarf planets will not be proposed at this time.

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Milky Way's Giant Black Hole Awoke From Slumber 300 Years Ago

Using NASA,Japanese, and European X-ray satellites, a team of Japanese astronomers has discovered that our galaxy's central black hole let loose a powerful flare three centuries ago.

The finding helps resolve a long-standing mystery: why is the Milky Way's black hole so quiescent? The black hole, known as Sagittarius A* (pronounced "A-star"), is a certified monster, containing about 4 million times the mass of our Sun. Yet the energy radiated from its surroundings is billions of times weaker than the radiation emitted from central black
holes in other galaxies.

"We have wondered why the Milky Way's black hole appears to be a slumbering giant," says team leader Tatsuya Inui of Kyoto University in Japan. "But now we realize that the black hole was far more active in the past. Perhaps it's just resting after a major outburst."

The new study, which will appear in the Publications of the Astronomical Society of Japan, combines results from Japan's Suzaku and ASCA X-ray satellites, NASA's Chandra X-ray Observatory, and the European Space Agency's XMM-Newton X-ray Observatory.

The observations, collected between 1994 and 2005, revealed that clouds of gas near the central black hole brightened and faded quickly in X-ray light as they responded to X-ray pulses emanating from just outside the black hole. When gas spirals inward toward the black hole, it heats up to millions of degrees and emits X-rays. As more and more matter piles up near
the black hole, the greater the X-ray output.

These X-ray pulses take 300 years to traverse the distance between the central black hole and a large cloud known as Sagittarius B2, so the cloud responds to events that occurred 300 years earlier. When the X-rays reach the cloud, they collide with iron atoms, kicking out electrons that are close to the atomic nucleus. When electrons from farther out fill in these gaps, the iron atoms emit X-rays. But after the X-ray pulse passes through, the cloud fades to its normal brightness.

Amazingly, a region in Sagittarius B2 only 10 light-years across varied considerably in brightness in just 5 years. These brightenings are known as light echoes. By resolving the X-ray spectral line from iron, Suzaku's observations were crucial for eliminating the possibility that subatomic particles caused the light echoes.

"By observing how this cloud lit up and faded over 10 years, we could trace back the black hole's activity 300 years ago," says team member Katsuji Koyama of Kyoto University. "The black hole was a million times brighter three centuries ago. It must have unleashed an incredibly powerful flare."

This new study builds upon research by several groups who pioneered the light-echo technique. Last year, a team led by Michael Muno, who now works at the California Institute of Technology in Pasadena, Calif., used Chandra observations of X-ray light echoes to show that Sagittarius A* generated a powerful burst of X-rays about 50 years ago -- about a dozen years before
astronomers had satellites that could detect X-rays from outer space. "The outburst three centuries ago was 10 times brighter than the one we detected," says Muno.

The galactic center is about 26,000 light-years from Earth, meaning those on Earth see events as they occurred 26,000 years ago. Astronomers still lack a detailed understanding of why Sagittarius A* varies so much in its activity. One possibility, says Koyama, is that a supernova a few centuries ago plowed up gas and swept it into the black hole, leading to a temporary feeding frenzy that awoke the black hole from its slumber and produced the giant flare.

Launched in 2005, Suzaku is the fifth in a series of Japanese satellites devoted to studying celestial X-ray sources and is managed by the Japan Aerospace Exploration Agency (JAXA). This mission is a collaborative effort between Japanese universities and institutions and NASA Goddard Spaceflight Center.

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Astronomers Find Grains of Sand Around Distant Stars

In a find that sheds light on how Earth-like planets may form, astronomers this week report finding the first evidence of small, sandy particles orbiting a newborn solar system at about the same distance as the Earth orbits the sun. The report will be published online this week by the journal Nature.

"Precisely how and when planets form is an open question," says study co-author Christopher Johns-Krull, assistant professor of physics and astronomy at Rice University. "We believe the disk-shaped clouds of dust around newly formed stars condense, forming microscopic grains of sand that eventually go on to become pebbles, boulders and whole planets."

In previous studies, astronomers have used infrared heat signals to identify microscopic dust particles around distant stars, but the method isn't precise enough to tell astronomers just how big they become, and whether the particles orbit near the star, like the Earth does the sun, or much further away at a distance more akin to Jupiter or Saturn.

In the new study, Johns-Krull and co-authors in the United States, Germany and Uzbekistan used reflected light from the sand itself to confirm the Earth-like orbit of grainy particles around a pair of stars called KH-15D in the constellation Monoceros. The stars are about 2,400 light years from Earth in the Cone Nebula, and they are only about 3 million years old, compared to the sun's 4.5 billion years.

"We were attracted to this system because it appears bright and dim at different times, which is odd," Johns-Krull says.

The researchers found that the Earth has a nearly edge-on view of KH-15D. From this perspective, the disk blocks one of the stars from view, but its twin has an eccentric orbit that causes it to rise above the disk at regular intervals.

"These eclipses let us study the system with the star there and with the star effectively not there," Johns-Krull says. "It's a very fortuitous arrangement because when the star is there all the time, it's so bright that we can't see the sand."

The team conducted both photometric and spectrographic analyses of data collected during the past 12 years from a dozen observatories, including the McDonald Observatory in west Texas, the Keck Observatory in Hawaii and the VLT on Mount Paranal in Chile.

"Because of how the light is being reflected there are opportunities to make observations about the chemical composition of these sand-like particles," says co-author William Herbst, an astronomer at Wesleyan University in Middletown, Conn. "That's very exciting because it opens up so many doors for new type of research on this disk."

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Light Gives Asteroids Spin

Astronomers have observed an asteroid change the rate at which it spins for the first time, and shown that this is due to a theoretical effect predicted but never before seen. The international team of scientists from Europe and the United States used a range of telescopes to find that the asteroid is rotating faster by 1 millisecond every year.

The acceleration in the rate of rotation is due to heating of the asteroid’s surface by the Sun. Eventually it may spin faster than any known asteroid in the solar system. The Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect is believed to alter the way small bodies in the solar system rotate. YORP is a torque due to sunlight shining on the surfaces of asteroids and meteoroids and warming their surfaces, leading to a gentle recoil effect as the heat is emitted. By analogy, if one were to shine light on a propeller over a long enough period, it would start spinning.

Although this is an almost immeasurably weak force, astronomers believe it may be responsible for spinning some asteroids up so fast that they break apart, perhaps leading to the formation of binary asteroids. Others may be slowed down so that they take many days to rotate once. The YORP effect also plays an important role in changing the orbits of asteroids between Mars and Jupiter, including their delivery to planet-crossing orbits.

Despite its importance, the effect has never been seen acting on a solar system body, until now. Using extensive optical and radar imaging from powerful Earth-based observatories, astronomers have directly observed the YORP effect in action on a small near-Earth asteroid, known as (54509) 2000 PH5. This work is reported in two companion papers, in the March edition of Science Express, by Stephen Lowry et al. (Queens University Belfast, UK) and Patrick Taylor et al. (Cornell University, Ithaca, NY, USA).

Shortly after its discovery in 2000, it was realized that this asteroid would be the ideal candidate for such a YORP detection. At just 114m in diameter, it is relatively small and so more susceptible to the effect. Also, it rotates very fast, with one day on the asteroid lasting just over 12 Earth minutes, implying that the YORP effect may have been acting on it for some time. With this in mind, the team of radar and optical astronomers undertook a long term monitoring campaign of the asteroid with the aim of detecting any tiny changes in the spin-rate.

Over a 4 year time span, Stephen Lowry, Alan Fitzsimmons and colleagues took images of the asteroid at a range of telescope sites including the 8.2m Very Large Telescope array and the 3.5m New Technology Telescope of the European Southern Observatory in Chile, the 3.5m telescope at Calar Alto, Spain, along with a suite of other telescopes from the Czech Republic, the Canary Islands, Hawaii, Spain and Chile. With these facilities the astronomers measured the slight brightness variations as the asteroid rotated.

Over the same time period, the radar team led by Patrick Taylor and Jean-Luc Margot of Cornell University employed the unique capabilities of the Arecibo Observatory in Puerto Rico and the Goldstone radar facility in California to observe the asteroid by ‘bouncing’ a radar pulse off the asteroid and analyzing its echo. With this technique astronomers can reconstruct a 3-D model of the asteroid’s shape, with the necessary detail to allow a theoretical YORP value to be derived and compared with the actual observed spin-rate change seen at optical wavelengths. With careful analysis of the optical data, the asteroid’s spin rate was seen to steadily increase with time, at a rate that can be explained by YORP theory. Most significantly, the effect was observed year after year.

Furthermore, this number was elegantly supported via analysis of the combined radar and optical data, as it was required that the asteroid increase its spin-rate at exactly this rate in order for a satisfactory 3-D shape model to be determined.

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