Free Range Brown Dwarfs

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Using two of the world’s largest optical-infrared telescopes, the Subaru Telescope in Hawaii and the Very Large Telescope (VLT) in Chile, an international team of astronomers has discovered more than two dozen brown dwarf stars floating around in two galactic clusters. During the Substellar Objects in Nearby Young Clusters (SONYC) survey, these “failed stars” came to their attention by showing up in extremely deep images of the NGC 1333 and rho Ophiuchi star clusters at both optical and infrared wavelengths. To make the findings even more exciting, these stellar curiosities outnumbered the “normal” stars in one cluster!

“Our findings suggest once again that objects not much bigger than Jupiter could form the same way as stars do. In other words, nature appears to have more than one trick up its sleeve for producing planetary mass objects,” says Professor Ray Jayawardhana, Canada Research Chair in Observational Astrophysics at the University of Toronto and leader of the international team. Their discovery will be published in two upcoming papers in the Astrophysical Journal and will be presented this week at a scientific conference in Garching, Germany.

Spectra of several brown dwarfs in the young star cluster NGC1333, taken with the FMOS instrument on the Subaru Telescope. The spectra show a characteristic peak around 1670nm. Water steam in a brown dwarf's atmosphere absorbs radiation on both sides of the peak. The plot shows that the strength of the water absorption increases in cooler objects (from 3000 to 2200K). FMOS allows astronomers to take spectra for many objects simultaneously, a crucial advantage for the SONYC Survey. Credit: SONYC Team/Subaru Telescope

Using spectroscopy, the researchers were able to separate candidate brown dwarfs by their red color. But there’s more to the story than just hues. In this case, it’s the identification of one that’s only about six times more massive than Jupiter. Located in NGC 1333, it is the smallest known free-floating object to date. What does that mean? “Its mass is comparable to those of giant planets, yet it doesn’t circle a star. How it formed is a mystery,” said Aleks Scholz of the Dublin Institute for Advanced Studies in Ireland, lead author of the first paper.

Brown dwarfs are indeed unusual. They walk a fine line between planet and star – and may have once been in stellar orbit, only to be ejected at some point in time. But in this circumstance, all of the brown dwarfs found in this particular cluster have very low mass – only about twenty times that of Jupiter. “Brown dwarfs seem to be more common in NGC 1333 than in other young star clusters. That difference may be hinting at how different environmental conditions affect their formation,” said Koraljka Muzic of the University of Toronto in Canada, lead author of the second paper.

“We could not have made these exciting discoveries if not for the remarkable capabilities of Subaru and the VLT. Instruments that can image large patches of the sky and take hundreds of spectra at once are key to our success,” said Motohide Tamura of the National Astronomical Observatory of Japan.

Free-range brown dwarfs? I’ll take mine over easy…

Original Story Source: Subaru Telescope News.

Even the Early Universe Had the Ingredients for Life

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For us carbon-based life forms, carbon is a fairly important part of the chemical makeup of the Universe. However, carbon and oxygen were not created in the Big Bang, but rather much later in stars. How much later? In a surprising find, scientists have detected carbon much earlier in the Universe’s history than previously thought.

Researchers from Ehime University and Kyoto University have reported the detection of carbon emission lines in the most distant radio galaxy known. The research team used the Faint Object Camera and Spectrograph (FOCAS) on the Subaru Telescope to observe the radio galaxy TN J0924-2201. When the research team investigated the detected carbon line, they determined that significant amounts of carbon existed less than a billion years after the Big Bang.

How does this finding contribute to our understanding of the chemical evolution of the universe and the possibilities for life?

To understand the chemical evolution of our universe, we can start with the Big Bang. According to the Big Bang theory, our universe sprang into existence about 13.7 billion years ago. For the most part, only Hydrogen and Helium ( and a sprinkle of Lithium) existed.

So how do we end up with everything past the first three elements on the periodic table?

Simply put, we can thank previous generations of stars. Two methods of nucleosythesis (element creation) in the universe are via nuclear fusion inside stellar cores, and the supernovae that marked the end of many stars in our universe.

Over time, through the birth and death of several generations of stars, our universe became less “metal-poor” (Note: many astronomers refer to anything past Hydrogen and Helium as metals”). As previous generations of stars died out, they “enriched” other areas of space, allowing future star-forming regions to have conditions necessary to form non-star objects such as planets, asteroids, and comets. It is believed that by understanding how the universe created heavier elements, researchers will have a better understanding of how the universe evolved, as well as the sources of our carbon-based chemistry.

So how do astronomers study the chemical evolution of our universe?

By measuring the metallicity (abundance of elements past Hydrogen on the periodic table) of astronomical objects at various redshifts, researchers can essentially peer back into the history of our universe. When studied, redshifted galaxies show wavelengths that have been stretched (and reddened, hence the term redshift) due to the expansion of our universe. Galaxies with a higher redshift value (known as “z”) are more distant in time and space and provide researchers information about the metallicity of the early universe. Many early galaxies are studied in the radio portion of the electromagnetic spectrum, as well as infra-red and visual.

The research team from Kyoto University set out to study the metallicity of a radio galaxy at higher redshift than previous studies. In their previous studies, their findings suggested that the main era of increased metallicity occurred at higher redshifts, thus indicating the universe was “enriched” much earlier than previous believed. Based on the previous findings, the team then decided to focus their studies on galaxy TN J0924-2201 – the most distant radio galaxy known with a redshift of z = 5.19.

The deep optical spectrum of TN J0924-2201 obtained with FOCAS on the Subaru Telescope. The red arrows point to the carbon emission line.

The research team used the FOCAS instrument on the Subaru Telescope to obtain an optical spectrum of galaxy TN J0924-2201. While studying TN J0924-2201, the team detected, for the first time, a carbon emission line (See above). Based on the detection of the carbon emission line, the team discovered that TN J0924-2201 had already experienced significant chemical evolution at z > 5, thus an abundance of metals was already present in the ancient universe as far back as 12.5 billion years ago.

If you’d like to read the team’s findings you can access the paper Chemical properties in the most distant radio galaxy – Matsuoka, et al at: http://arxiv.org/abs/1107.5116

Source: NAOJ Press Release

Uncloaking Type Ia Supernovae

This three-color composite of a portion of the Subaru Deep Field shows mostly galaxies with a few stars. The inset shows one of the 10 most distant and ancient Type Ia supernovae discovered by the American, Israeli and Japanese team.

Type Ia supernovae… Right now they are one of the most studied – and most mysterious – of all stellar phenomenon. Their origins are sheer conjecture, but explaining them is only half the story. Taking a look back into almost the very beginnings of our Universe is what it’s all about and a team of Japanese, Israeli, and U.S. astronomers have employed the Subaru Telescope to give us the most up-to-date information on these elementally explosive cosmic players.

By understanding the energy release of a Type Ia supernova, astronomers have been able to measure unfathomable distances and speculate on dark energy expansion. It was popular opinion that what caused them was a white dwarf star pulling in so much matter from a companion that it finally exploded, but new research points in a different direction. According to the latest buzz, it may very well be the merging of two white dwarfs.

“The nature of these events themselves is poorly understood, and there is a fierce debate about how these explosions ignite,” said Dovi Poznanski, one of the main authors of the paper and a post-doctoral fellow at the University of California, Berkeley, and Lawrence Berkeley National Laboratory.

“The main goal of this survey was to measure the statistics of a large population of supernovae at a very early time, to get a look at the possible star systems,” he said. “Two white dwarfs merging can explain well what we are seeing.”

Can you imagine the power behind this theory? The Type Ia unleashed a thermonuclear reaction so strong that it is able to be traced back to nearly the beginning of expansion after the Big Bang. By employing the Subaru telescope and its prime focus camera (Suprime-Cam), the team was able to focus their attention four times on a small area named the Subaru Deep Field. In their imaging they caught 150,000 individual galaxies containing a total of 40 Type Ia supernova events. One of the most incredible parts of these findings is that these events happened about five times more frequently in the early Universe. But no worries… Even though the mechanics behind them are still poorly understood, they still serve as “cosmic distance markers”.

“As long as Type Ias explode in the same way, no matter what their origin, their intrinsic brightnesses should be the same, and the distance calibrations would remain unchanged.” says Alex Filippenko, UC Berkeley professor of astronomy.

Original Story Source: University of Berkeley News Release. For Further Reading: National Astronomical Observatory of Japan: Subaru News Release.

Red-Burning Galaxies… Let’s Get The Party Started!

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Utilizing the Subaru Telescope, a research team of astronomers from the University of Tokyo and the National Astronomical Society of Japan (NAOJ) used a wide-field image to take a look four billion years back in time. The object of their interest was a galaxy cluster, but what really took their fancy wasn’t the old matrons – it was the red star-forming galaxies hanging around the edges.

Just exactly what is a “red-burning galaxy”? Astronomers hypothesize they might be the transitional key between the young and old… and present at a party that shows dramatic evolution. It’s not the fact that such galaxies exist within galactic clusters, but why they seem to appear along the outskirts.

When galaxies first began forming under the weight of their own gravity some ten billion years ago, they either became part of big clusters or small groups. As they came together, they took on properties of their environment – just as party goers tend to group together where interests are similar. At a galactic get-together with high density, galaxies form into lenticular or elliptical, while the solitary wall flowers tend toward spiral structure. But exactly how they form and evolve is one of astronomy’s greatest enigmas.

A panoramic view of the CL0939+4713 cluster located 4 billion light years away from Earth. Images were captured with the Subaru Prime Focus Camera (Suprime-Cam), all of which are a composite of a B-band image (blue), a R-band image (green), and a z'-band image (red). Left 27 arcmin x 27 arcmin field of view. Top-right: Close-up view of the central cluster region, 2.5 arcmin x 2.5 arcmin field of view. Bottom-right: Example of the concentration of red-burning galaxies, which are marked with red squares.

To help solve the mystery, researchers are looking further back into the past. A research team led by Dr. Yusei Koyama used the Subaru Prime Focus Camera (Suprime-Cam) to carry out a panoramic observation targeting a relatively well-known rich cluster, CL0939+4713. By using a special filter that separates the hydrogen-alpha emission lline Koyama’s team members identified more than 400 galaxies showing a narrowband excess which could denote the star formation process. Strangely enough, it was these very galaxies that showed an impressive amount of red and were located in groups well away from the main body.

Needless to say, this opened the door to even more questions. Where did they come from and why are they concentrated in groups and not clusters? At this point, who knows? Astronomers are positive the “red-burning galaxies” get their properties from starbirth – not elderly populations. They also anticipate the main galaxy cluster will one day absorb these strays into the main body as well. How can they tell? Just like the party, the red-burning galaxies are already changing in relationship to their environment. Older galaxies that no longer have active star-forming regions seem to be increasing in the groups, exactly where the red-burners are most frequently found.

“This suggests that the red-burning galaxies are related to the increase in old galaxies, and that they are likely to be in a transitional phase from a younger to an older generation. The finding that such transitional galaxies are located most frequently within group environments shows that galaxy groups are the key environments for understanding how environment shapes the evolution of galaxies.” says the Subaru research team. “This should be an important and exciting step toward a more complete understanding of the environments shaping the galaxies in the present-day Universe.”

Party on, dudes…

Original Story Source: Subaru Telescope Press Release.

Japanese Astronomy Pushes on After Hard Year

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From faulty spacecraft to two damaged facilities, the past year has been a tough year for Japan’s astronomical programs. Yes despite the setbacks, Japan has already begun working to fix every problem they’ve faced in this difficult year.

The troubles started late last year as Japan’s Venus exploring spacecraft, Akatsuki failed to properly enter orbit around Venus. Ultimately, the failure was blamed on a faulty valve that didn’t allow the thruster to fire for the full length of the burn necessary to transfer into the correct orbit. Instead, the craft is now in a wide orbit around the Sun. The organization in charge of the probe, the Japan Aerospace Exploration Agency (JAXA) announced earlier this month that they will “attempt to reignite the damaged thruster nozzle” and, if the test goes well, can try again for an orbital insertion in November 2015.

The next setback came with the devastating March 11th earthquake which the facilities being used to study the samples returned from the sample and return mission Hayabusa were damaged. While the particles were safe, the sensitive accelerators that are used to study them suffered some damage. Restoration work is already underway and the teams in charge expect some operations to resume as early as this fall. Other instruments may take until early next year to resume operation. Despite the damage, the preliminary data (done before the Earthquake) has confirmed the particles are from the visited asteroid. They contain minerals such as olivine and iron sulfide contained in a rocky-type asteroid. No organic materials have been detected.

More recently, Japan’s flagship observatory, Subaru atop Mauna Kea, Hawaii, was damaged when coolant leaked onto several instruments as well as the primary mirror, halting operations early last month. According to the National Astronomical Observatory of Japan (NAOJ) which maintains the telescope, the mirror was washed with water which was successful in restoring its functionality. The primary camera, the Subaru Prime Focus Camera (Suprime-Cam) and its auxiliary equipment were also affected and are currently being inspected. However, the telescope has a second focus, known as a Nasmyth focus. Several instruments which make use of this focus, including the High Dispersion Spectograph, the 188-element Adaptive Optics system, the Infrared Camera and Spectrograph, and the High Contrast Instrument for the Subaru Next Generation Adaptive Optics, were all unaffected. With the cleaning of the mirror and the use of these instruments, the telescope was able to resume operations on the night of July 22.

With any luck, fortunes will continue to improve for Japan and their hard work and dedication can help them to overcome these issues. Ganbatte!

Subaru 8-meter Telescope Damaged by Leaking Coolant

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A “serious hardware incident” has shut down the Subaru Telescope indefinitely. A leak allowed orange-colored coolant to spill over the primary mirror and into the main camera, as well as into other instruments and the structure of the telescope. The damage is still being assessed. During the clean-up and recovery of equipment, nighttime observations have been suspended, as well as daytime summit tours of the telescope.

An announcement posted on the Subaru telescope website said that operators detected an error signal while shutting down the observation system at the end of the night shift during the early morning of Saturday, July 2, 2011.

When engineers arrived to assess the situation, they found extensive leakage of coolant (ethylene glycol) over most of the entire telescope. The leak originated from the “top unit” of the telescope, which is located at the center of the top ring and includes the Subaru Prime Focus Camera (Suprime-Cam) and auxiliary optics.

Although they promptly shut off the supply of coolant, a significant amount of leakage had already occurred, from the top unit itself down to the tertiary mirror, the primary mirror and some of its actuators, the Faint Object Camera and Spectrograph (FOCAS, a Cassegrain instrument) and its auxiliary optics, and the telescope floor.

The engineers attempted to clean up and remove as much coolant as possible. However, such areas as optics, control circuits, and the inside of Suprime-Cam and FOCAS were inaccessible during the initial clean-up.
The coolant consists of a mixture of water and ethylene glycol, a liquid commonly used in a vehicle’s radiator for cooling. The coolant is not corrosive and does not damage the primary mirror, which has a foundation of glass.

The Subaru Telescope is located on the Mauna Kea on the Big Island of Hawaii, with offices in the town of Hilo. The Subaru website said they will post updates on the status of the telescope and its recovery.

Source: Subaru Telescope website

Subaru Telescope Takes Montage of Hayabusa’s Return to Earth

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The world watched and waited for the Hayabusa spacecraft to make its return to Earth on June 13, 2010 and the people of Japan — who built and launched the little spacecraft that could (and did!) — were especially hopeful in watching and waiting. Japan’s Subaru Telescope (although located on Mauna Kea in Hawaii) turned its expectant eyes towards Hayabusa and captured the spacecraft’s flight between the Moon and Earth in 11 different images.

A note from the Subaru Telescope team:

During the busy time preparing the observations, Doctor Masafumi Yagi and his team managed to maneuver the telescope just in time to catch Hayabusa before it disappeared down south in the twilight sky. At that time, Hayabusa was a little less than half way between Moon and Earth. Five seconds exposures, each spaced by 35 – 50 seconds in the V filter with Suprime Cam, it showed up in clear trace at the position expected to be. Brightness is estimated to be only 21 magnitudes. At this level, one can see a background galaxy clearly.

We are waiting to hear more from the project team at ISAS/JAXA. In the meantime, congratulations to all who are involved in this unprecedented endeavor.

A GIF animation of the 11 images is available here — but be warned, the file is huge. You can click on the top image for a full-sized huge-ified image, too.

And here are some images of the recovery teams who picked up the sample return canister in the Woomera Prohibited Area in Australia. The canister will be taken to Japan and opened in a few weeks, or perhaps months, after rigorous testing. Only then will we find out if any asteroid samples made it in the canister for the ride back to Earth.

Recovery team makes sure all is safe with the sample return canister. Credit: JAXA
The recovery team handles the heat sheild for the Hayabusa sample return capsule. Credit: JAXA, Hayabusa Twitter feed.
JAXA's Hayabusa space capsule is transported inside a box to a clean room inside the Instrumentation Building at the Woomera Test Range, South Australia. Credit: Australian Science Media Centre

You can see more images of the canister retrieval at the Hayabusa Twitpic page and the Australian Science Media Centre’s Flickr page

Source: Subaru

Team Finds Most-Distant Galaxy Cluster Ever Seen

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Like a location from Star Wars, this galaxy cluster is far, far away and with origins a long, long time ago. With the ungainly name of SXDF-XCLJ0218-0510, this cluster is actually the most distant cluster of galaxies ever seen. It is a whopping 9.6 billion light years away, and X-ray and infrared observations show that the cluster hosts predominantly old, massive galaxies. This means the galaxies formed when the universe was still very young, so finding this cluster and being able to see it is providing new information not only about early galaxy evolution but also about history of the universe as a whole.

An international team of astronomers from the Max Planck Institute for Extraterrestrial Physics, the University of Tokyo and the Kyoto University discovered this cluster using the Subaru telescope along with the XMM-Newton space observatory to look in different wavelengths.

Using the Multi-Object Infrared Camera and Spectrometer (MOIRCS) on the Subaru telescope, the team was able to look in near-infrared wavelengths, where the galaxies are most luminous.

“The MOIRCS instrument has an extremely powerful capability of measuring distances to galaxies. This is what made our challenging observation possible,” said Masayuki Tanaka from the University of Tokyo. “Although we confirmed only several massive galaxies at that distance, there is convincing evidence that the cluster is a real, gravitationally bound cluster.”

Like a contour map, the arrows in the image above indicate galaxies that are likely located at the same distance, clustered around the center of the image. The contours indicate the X-ray emission of the cluster. Galaxies with confirmed distance measurements of 9.6 billion light years are circled. The combination of the X-ray detection and the collection of massive galaxies unequivocally proves a real, gravitationally bound cluster.

That the individual galaxies are indeed held together by gravity is confirmed by observations in a very different wavelength regime: The matter between the galaxies in clusters is heated to extreme temperatures and emits light at much shorter wavelengths than visible to the human eye. The team therefore used the XMM-Newton space observatory to look for this radiation in X-rays.

“Despite the difficulties in collecting X-ray photons with a small effective telescope size similar to the size of a backyard telescope, we detected a clear signature of hot gas in the cluster,” said Alexis Finoguenov from the Max Planck Institute for Extraterrestrial Physics.

The combination of these different observations in what are invisible wavelengths to the human eye led to the pioneering discovery of the galaxy cluster at a distance of 9.6 billion light years – some 400 million light years further into the past than the previously most distant cluster known.

An analysis of the data collected about the individual galaxies shows that the cluster contains already an abundance of evolved, massive galaxies that formed some two billion years earlier. As the dynamical processes for galaxy aging are slow, presence of these galaxies requires the cluster assembly through merger of massive galaxy groups, each nourishing its dominant galaxy. The cluster is therefore an ideal laboratory for studying the evolution of galaxies, when the universe was only about a third of its present age.

As distant galaxy clusters are also important tracers of the large scale structure and primordial density fluctuations in the universe, similar observations in the future will lead to important information for cosmologists. The results obtained so far demonstrate that current near infrared facilities are capable of providing a detailed analysis of distant galaxy populations and that the combination with X-ray data is a powerful new tool. The team therefore is continuing the search for more distant clusters.

Source: Max Planck Institute for Extraterrestrial Physics