Posted on by Nancy Atkinson

Ancient Quasar Shines Brightly, But All the Galaxy’s Stars Are Missing

Hubble Space Telescope image of J1148+5251. Credit: NASA/ESA/M. Mechtley, R. Windhorst, Arizona State University

Quasars have been the best and most easily observed beacons for astronomers to probe the distant Universe, and one of the most distant and brightest quasars is providing a bit of a surprise. Astronomers studying a distant galaxy, dubbed J1148+5251 and which contains a bright quasar, are seeing only the quasar and not the host galaxy itself. It has been thought that the quasar has been feeding on a handful of stars every year in order to bulk up to its size of three billion solar masses over just a few hundred million years. But where are all the stars?

Likely, the quasar hasn’t gone on a feeding frenzy and eaten everything in sight! But it might be eating on the sly. Near infrared views with the Hubble Space Telescope’s Wide Field Camera 3 are only providing hints of what might be taking place: the galaxy is so enshrouded with dust that none of the starlight can be seen; only the bright, blaring quasar shines through. Just how many stars this quasar is eating is now uncertain, as the carnage is taking place undercover.

While most early galaxies contain hardly any dust — the early universe was dust-free until the first generation of stars started making dust through nuclear fusion – previous submillimeter observations showed this galaxy harbors large amounts of dust, so that is somewhat of a mystery, too.

So how could this all be happening?

Artist’s impression of one of the most distant, oldest, brightest quasars ever seen is hidden behind dust. The dust is also hiding the view of the underlying galaxy of stars that the quasar is presumably embedded in. (Credit: NASA/ESA/G.Bacon, STScI)

“If you want to hide the stars with dust, you need to make lots of short-lived massive stars earlier on that lose their mass at the end of their lifetime. You need to do this very quickly, so supernovae and other stellar mass-loss channels can fill the environment with dust very quickly,” said Rogier Windhorst of Arizona State University (ASU), Tempe, Ariz.
“You also have to be forming them throughout the galaxy to spread the dust throughout the galaxy,” added Matt Mechtley, also of ASU.

This quasar was first identified in the Sloan Digital Sky Survey (SDSS) and the follow-up submillimeter observations showed significant dust but not how and where it was distributed.

Windhorst and his team used Hubble to very carefully subtract light from the quasar image and look for the glow of surrounding stars. They did this by looking at the glow of a reference star in the sky near the quasar and using it as a template to remove the quasar light from the image. Once the quasar was removed, no significant underlying starlight was detected. The underlying galaxy’s stars could have been easily detected, had they been present and relatively unobscured by dust in at least some locations.

“It is remarkable that Hubble didn’t find any of the underlying galaxy,” said Windhorst. “The underlying galaxy is everywhere much fainter than expected, and therefore must be in a very dusty environment throughout. It’s one of the most rip-roaring forest fires in the universe. It’s creating so much smoke that you’re not seeing any starlight, anywhere. The forest fire is complete, not a tree is spared.”

Because we don’t see the stars, we can rule out that the galaxy that hosts this quasar is a normal galaxy,” said Mechtley. “It’s among the dustiest galaxies in the universe, and the dust is so widely distributed that not even a single clump of stars is peeking through. We’re very close to a plausible detection, in the sense that if we had gone a factor of two deeper we might have detected some light from its young stars, even in such a dusty galaxy.”

This result was published in the Sept. 10 issue of the Astrophysical Journal Letters in the team’s paper.

The only way to get to the bottom of this mystery, Windhorst said, is to wait for the James Webb Space Telescope to launch and come online.

“The Webb telescope is designed to make a definitive detection of this,” he said. “ We will get solid detections of the stars with Webb’s better sensitivity to longer wavelengths of light, which will better probe the dusty regions in these young galaxies.”

The Webb telescope will also have the infrared sensitivity to peer all the way back to 200 million years after the Big Bang. If galaxies started forming stars at this early epoch, Webb is designed and being built to detect them.

So only then will the true nature – and potential carnage – of this system be revealed.

Read the team’s paper.
Source: NASA

Posted on by Nancy Atkinson

Hubble Studies Dark Matter Filament in 3-D

Hubble’s view of massive galaxy cluster MACS J0717.5+3745. The large field of view is a combination of 18 separate Hubble images. Credit:
NASA, ESA, Harald Ebeling (University of Hawaii at Manoa) & Jean-Paul Kneib (LAM)

Earlier this year, astronomers using the Hubble Space Telescope were able to identify a slim filament of dark matter that appeared to be binding a pair of distant galaxies together. Now, another filament has been found, and scientists a have been able to produce a 3-D view of the filament, the first time ever that the difficult-to-detect dark matter has been able to be measured in such detail. Their results suggest the filament has a high mass and, the researchers say, that if these measurements are representative of the rest of the Universe, then these structures may contain more than half of all the mass in the Universe.

Dark matter is thought to have been part of the Universe from the very beginning, a leftover from the Big Bang that created the backbone for the large-scale structure of the Universe.

“Filaments of the cosmic web are hugely extended and very diffuse, which makes them extremely difficult to detect, let alone study in 3D,” said Mathilde Jauzac, from Laboratoire d’Astrophysique de Marseille in France and University of KwaZulu-Natal, in South Africa, lead author of the study.

The team combined high resolution images of the region around the massive galaxy cluster MACS J0717.5+3745 (or MACS J0717 for short) – one of the most massive galaxy clusters known — and found the filament extends about 60 million light-years out from the cluster.

The team said their observations provide the first direct glimpse of the shape of the scaffolding that gives the Universe its structure. They used Hubble, NAOJ’s Subaru Telescope and the Canada-France-Hawaii Telescope, with spectroscopic data on the galaxies within it from the WM Keck Observatory and the Gemini Observatory. Analyzing these observations together gives a complete view of the shape of the filament as it extends out from the galaxy cluster almost along our line of sight.

The team detailed their “recipe” for studying the vast but diffuse filament. .

First ingredient: A promising target. Theories of cosmic evolution suggest that galaxy clusters form where filaments of the cosmic web meet, with the filaments slowly funnelling matter into the clusters. “From our earlier work on MACS J0717, we knew that this cluster is actively growing, and thus a prime target for a detailed study of the cosmic web,” explains co-author Harald Ebeling (University of Hawaii at Manoa, USA), who led the team that discovered MACS J0717 almost a decade ago.

Second ingredient: Advanced gravitational lensing techniques. Albert Einstein’s famous theory of general relativity says that the path of light is bent when it passes through or near objects with a large mass. Filaments of the cosmic web are largely made up of dark matter [2] which cannot be seen directly, but their mass is enough to bend the light and distort the images of galaxies in the background, in a process called gravitational lensing. The team has developed new tools to convert the image distortions into a mass map.

Third ingredient: High resolution images. Gravitational lensing is a subtle phenomenon, and studying it needs detailed images. Hubble observations let the team study the precise deformation in the shapes of numerous lensed galaxies. This in turn reveals where the hidden dark matter filament is located. “The challenge,” explains co-author Jean-Paul Kneib (LAM, France), “was to find a model of the cluster’s shape which fitted all the lensing features that we observed.”

Finally: Measurements of distances and motions. Hubble’s observations of the cluster give the best two-dimensional map yet of a filament, but to see its shape in 3D required additional observations. Colour images [3], as well as galaxy velocities measured with spectrometers [4], using data from the Subaru, CFHT, WM Keck, and Gemini North telescopes (all on Mauna Kea, Hawaii), allowed the team to locate thousands of galaxies within the filament and to detect the motions of many of them.

A model that combined positional and velocity information for all these galaxies was constructed and this then revealed the 3D shape and orientation of the filamentary structure. As a result, the team was able to measure the true properties of this elusive filamentary structure without the uncertainties and biases that come from projecting the structure onto two dimensions, as is common in such analyses.

The results obtained push the limits of predictions made by theoretical work and numerical simulations of the cosmic web. With a length of at least 60 million light-years, the MACS J0717 filament is extreme even on astronomical scales. And if its mass content as measured by the team can be taken to be representative of filaments near giant clusters, then these diffuse links between the nodes of the cosmic web may contain even more mass (in the form of dark matter) than theorists predicted.

More info in this ESA HubbleCast video:

Source: ESA Hubble

Posted on by Nancy Atkinson

Watch Live Webcast: What Does Hubble’s Deepest Image of the Universe Reveal?

This image, called the Hubble eXtreme Deep Field (XDF), combines Hubble observations taken over the past decade of a small patch of sky in the constellation of Fornax. With a total of over two million seconds of exposure time, it is the deepest image of the Universe ever made, combining data from previous images including the Hubble Ultra Deep Field (taken in 2002 and 2003) and Hubble Ultra Deep Field Infrared (2009). The image covers an area less than a tenth of the width of the full Moon, making it just a 30 millionth of the whole sky. Yet even in this tiny fraction of the sky, the long exposure reveals about 5500 galaxies, some of them so distant that we see them when the Universe was less than 5% of its current age. The Hubble eXtreme Deep Field image contains several of the most distant objects ever identified. Credit: NASA

Astronomers using the Hubble Space Telescope recently released the deepest image of the sky ever obtained which reveals the faintest and most distant galaxies ever seen. The Hubble eXtreme Deep Field (XDF) is like a time machine, allowing us to see at how some galaxies looked just 450 million years after the Universe’s birth in the Big Bang.

Want to know more? The Kavli Foundation is hosting a live Q&A webcast on October 4 from 18:00- 18:30 UTC (11-11:30 am PDT) to provide the public a chance to ask questions of leading scientists about the image and the science behind it. Pascal Oesch, a Hubble Fellow at the University of California at Santa Cruz, and Michele Trenti, a researcher at the Kavli Institute for Cosmology, Cambridge at the University of Cambridge in the U.K., will discuss the image and answer questions about how the image was created and what it reveals about the early Universe. Watch the webcast below or at this link. Viewers may submit questions to the two Hubble researchers via Twitter using #KavliAstro or email to [email protected].

Lead image caption: The Hubble eXtreme Deep Field (XDF). Credit: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team

Posted on by Nancy Atkinson

Spitzer Provides Most Precise Measurement Yet of the Universe’s Expansion

Calibrated Period-luminosity Relationship for Cepheid variables.
Calibrated Period-luminosity Relationship for Cepheid variables. Courtesy Spitzer Space Telescope/IPAC.

This graph illustrates the Cepheid period-luminosity relationship, which scientists use to calculate the size, age and expansion rate of the Universe. Credit: NASA/JPL-Caltech/Carnegie

How fast is our Universe expanding? Over the decades, there have been different estimates used and heated debates over those approximations, but now data from the Spitzer Space Telescope have provided the most precise measurement yet of the Hubble constant, or the rate at which our universe is stretching apart. The result? The Universe is getting bigger a little bit faster than previously thought.

The newly refined value for the Hubble constant is 74.3 plus or minus 2.1 kilometers per second per megaparsec.

The most previous estimation came from a study from the Hubble Space Telescope, at 74.2 plus or minus 3.6 kilometers per second per megaparsec. A megaparsec is roughly 3 million light-years.

To make the new measurements, Spitzer scientists looked at pulsating stars called cephied variable stars, taking advantage of being able to observe them in long-wavelength infrared light. In addition, the findings were combined with previously published data from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) on dark energy. The new determination brings the uncertainty down to 3 percent, a giant leap in accuracy for cosmological measurements, scientists say.

WMAP obtained an independent measurement of dark energy, which is thought to be winning a battle against gravity, pulling the fabric of the universe apart. Research based on this acceleration garnered researchers the 2011 Nobel Prize in physics.

The Hubble constant is named after the astronomer Edwin P. Hubble, who astonished the world in the 1920s by confirming our universe has been expanding since it exploded into being 13.7 billion years ago. In the late 1990s, astronomers discovered the expansion is accelerating, or speeding up over time. Determining the expansion rate is critical for understanding the age and size of the universe.

“This is a huge puzzle,” said the lead author of the new study, Wendy Freedman of the Observatories of the Carnegie Institution for Science in Pasadena. “It’s exciting that we were able to use Spitzer to tackle fundamental problems in cosmology: the precise rate at which the universe is expanding at the current time, as well as measuring the amount of dark energy in the universe from another angle.” Freedman led the groundbreaking Hubble Space Telescope study that earlier had measured the Hubble constant.

Glenn Wahlgren, Spitzer program scientist at NASA Headquarters in Washington, said the better views of cepheids enabled Spitzer to improve on past measurements of the Hubble constant.

“These pulsating stars are vital rungs in what astronomers call the cosmic distance ladder: a set of objects with known distances that, when combined with the speeds at which the objects are moving away from us, reveal the expansion rate of the universe,” said Wahlgren.

Cepheids are crucial to the calculations because their distances from Earth can be measured readily. In 1908, Henrietta Leavitt discovered these stars pulse at a rate directly related to their intrinsic brightness.

To visualize why this is important, imagine someone walking away from you while carrying a candle. The farther the candle traveled, the more it would dim. Its apparent brightness would reveal the distance. The same principle applies to cepheids, standard candles in our cosmos. By measuring how bright they appear on the sky, and comparing this to their known brightness as if they were close up, astronomers can calculate their distance from Earth.

Spitzer observed 10 cepheids in our own Milky Way galaxy and 80 in a nearby neighboring galaxy called the Large Magellanic Cloud. Without the cosmic dust blocking their view, the Spitzer research team was able to obtain more precise measurements of the stars’ apparent brightness, and thus their distances. These data opened the way for a new and improved estimate of our universe’s expansion rate.

“Just over a decade ago, using the words ‘precision’ and ‘cosmology’ in the same sentence was not possible, and the size and age of the universe was not known to better than a factor of two,” said Freedman. “Now we are talking about accuracies of a few percent. It is quite extraordinary.”

“Spitzer is yet again doing science beyond what it was designed to do,” said project scientist Michael Werner at NASA’s Jet Propulsion Laboratory. Werner has worked on the mission since its early concept phase more than 30 years ago. “First, Spitzer surprised us with its pioneering ability to study exoplanet atmospheres,” said Werner, “and now, in the mission’s later years, it has become a valuable cosmology tool.”

The study appears in the Astrophysical Journal.

Paper on arXiv: A Mid-Infrared Calibration of the Hubble Constant

Source: JPL

Posted on by Nancy Atkinson

Hubble Goes to the eXtreme in Stunning New Deepest View Ever of the Universe

This image, called the Hubble eXtreme Deep Field (XDF), combines Hubble observations taken over the past decade of a small patch of sky in the constellation of Fornax. With a total of over two million seconds of exposure time, it is the deepest image of the Universe ever made, combining data from previous images including the Hubble Ultra Deep Field (taken in 2002 and 2003) and Hubble Ultra Deep Field Infrared (2009). The image covers an area less than a tenth of the width of the full Moon, making it just a 30 millionth of the whole sky. Yet even in this tiny fraction of the sky, the long exposure reveals about 5500 galaxies, some of them so distant that we see them when the Universe was less than 5% of its current age. The Hubble eXtreme Deep Field image contains several of the most distant objects ever identified. Credit: NASA

The Hubble eXtreme Deep Field (XDF) combines Hubble observations taken over the past decade of a small patch of sky in the constellation of Fornax. With a total of over two million seconds of exposure time, it is the deepest image of the Universe ever made. Credit: credit: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team

Oh my! The Hubble Space Telescope has just outdone itself, taking the deepest-ever view of the Universe. But the new image really is a compilation of work over the past ten years, as the eXtreme Deep Field, or XDF was assembled by combining ten years of observations, with over 2 million seconds of exposure time, taken of a patch of sky in the center of the original Hubble Ultra Deep Field from 2004. The XDF is a small fraction of the angular diameter of the full Moon.

The new full-color XDF image is even more sensitive than the Hubble Ultra Deep Field image from 2004 and the original Hubble Deep Field image from 1995. The new XDF image contains about 5,500 galaxies, even within its smaller field of view. The faintest galaxies are one ten-billionth the brightness that the unaided human eye can see.
Continue reading “Hubble Goes to the eXtreme in Stunning New Deepest View Ever of the Universe”

Posted on by Nancy Atkinson

Early Galaxy Found from the Cosmic ‘Dark Ages’

In the big image at left, the many galaxies of a massive cluster called MACS J1149+2223 dominate the scene. Gravitational lensing by the giant cluster brightened the light from the newfound galaxy, known as MACS 1149-JD, some 15 times. At upper right, a partial zoom-in shows MACS 1149-JD in more detail, and a deeper zoom appears to the lower right. Image credit: NASA/ESA/STScI/JHU

Take a close look at the pixelated red spot on the lower right portion of the image above, as it might be the oldest thing humanity has ever seen. This is a galaxy from the very early days of the Universe, and the light from the primordial galaxy traveled approximately 13.2 billion light-years before reaching the Spitzer and Hubble space telescopes. The telescopes — and the astronomers using them — had a little help from a gravitational lens effect to be able to see such a faint and distant object, which was shining way back when our Universe was just 500 million years old.

“This galaxy is the most distant object we have ever observed with high confidence,” said Wei Zheng, a principal research scientist in the department of physics and astronomy at Johns Hopkins University in Baltimore who is lead author of a new paper appearing in Nature. “Future work involving this galaxy, as well as others like it that we hope to find, will allow us to study the universe’s earliest objects and how the dark ages ended.”

This ancient and distant galaxy comes from an important time in the Universe’s history — one which astronomers know little about – the early part of the epoch of reionization, when the Universe began to move from the so-called cosmic dark ages. During this period, the Universe went from a dark, starless expanse to a recognizable cosmos full of galaxies. The discovery of the faint, small galaxy opens a window onto the deepest, most remote epochs of cosmic history.

“In essence, during the epoch of reionization, the lights came on in the universe,” said paper co-author Leonidas Moustakas, from JPL.

Because both the Hubble and Spitzer telescopes were used in this observation, this newfound galaxy, named MACS 1149-JD, was imaged in five different wavebands. As part of the Cluster Lensing And Supernova Survey with Hubble Program, the Hubble Space Telescope registered the newly described, far-flung galaxy in four visible and infrared wavelength bands. Spitzer measured it in a fifth, longer-wavelength infrared band, placing the discovery on firmer ground.

Objects at these extreme distances are mostly beyond the detection sensitivity of today’s largest telescopes. To catch sight of these early, distant galaxies, astronomers rely on gravitational lensing, where the gravity of foreground objects warps and magnifies the light from background objects. A massive galaxy cluster situated between our galaxy and MACS 1149-JD magnified the newfound galaxy’s light, brightening the remote object some 15 times and bringing it into view.

Astronomers use redshift to describe cosmic distances, and the ancient but newly-found galaxy has a redshift, of 9.6. The term redshift refers to how much an object’s light has shifted into longer wavelengths as a result of the expansion of the universe.

Based on the Hubble and Spitzer observations, astronomers think the distant galaxy was less than 200 million years old when it was viewed. It also is small and compact, containing only about 1 percent of the Milky Way’s mass. According to leading cosmological theories, the first galaxies indeed should have started out tiny. They then progressively merged, eventually accumulating into the sizable galaxies of the more modern universe.

The epoch of reionization refers to the period in the history of the Universe during which the predominantly neutral intergalactic medium was ionized by the emergence of the first luminous sources, and these first galaxies likely played the dominant role in lighting up the Universe. By studying reionization, astronomers can learn about the process of structure formation in the Universe, and find the evolutionary links between the smooth matter distribution at early times revealed by cosmic microwave background studies, and the highly structured Universe of galaxies and clusters of galaxies at redshifts of 6 and below.

This epoch began about 400,000 years after the Big Bang when neutral hydrogen gas formed from cooling particles. The first luminous stars and their host galaxies emerged a few hundred million years later. The energy released by these earliest galaxies is thought to have caused the neutral hydrogen strewn throughout the Universe to ionize, or lose an electron, a state that the gas has remained in since that time.

The paper is available here (pdf document).

Source: JPL

Posted on by Nancy Atkinson

Win a Hubble Photograph, Now Through September 16

We all hate to see the summer end (coming soon in the northern hemisphere) but before the September equinox arrives, the HubbleSite team is making the most of the last few days of summer by giving away copies of a few iconic images taken by the venerable Hubble Space Telescope. The End-of-Summer Hubble Picture Giveaway is a random drawing accessible via HubbleSite’s Facebook page. Three winners per day, selected randomly from Sept. 4-16 will receive one 16×20 print of one of three images: Mystic Mountain (as seen below), The Helix Nebula, or Barred Spiral Galaxy NGC 1300.

HubbleSite runs these drawings periodically on its Facebook page, but for readers of Universe Today, they are we’re offering an extra chance to win for users who enter a promo code in the appropriate field!

The code for Universe Today readers is UNIVTDAY.

So check out HubbleSite’s Facebook page, and also check out the HubbleSite website, chock full of all the images taken by HST.

So, enter every day — and don’t forget you can enter twice a day by using the special code for UT readers.

Thanks to the HubbleSite Facebook team!

Hubble’s ‘Mystic Mountain’ shows a mountain of dust and gas rising in the Carina Nebula. The top of a three-light-year tall pillar of cool hydrogen is being worn away by the radiation of nearby stars, while stars within the pillar unleash jets of gas that stream from the peaks. Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI)

Posted on by John Williams

Hubble’s Hidden Treasures Unveiled

A quick check of Hubble’s gallery shows just 1,300 images; however more than raw 700,000 images reside in a vast archive with hundreds of potentially jaw-dropping astronomical scenes just waiting to be uncovered. That was the idea behind the European Space Agency’s international contest called Hubble’s Hidden Treasures. And now with the hard work of amateur astronomers and more than 3,000 submissions, some of Hubble’s incredible celestial treasures are revealed.

“The response was impressive, with almost 3000 submissions,” the ESA said in a press release. “More than a thousand of these images were fully processed: a difficult and time-consuming task. We’ve already started featuring the best of these in our Hubble Picture of the Week series.”

The top 10 images selected in the Hubble Hidden Treasures basic imaging category. Top row: NGC 6300 by Brian Campbell, V* PV Cephei by Alexey Romashin, IRAS 14568-6304 by Luca Limatola, NGC 1579 by Kathlyn Smith, B 1608+656 by Adam Kill Bottom row: NGC 4490 by Kathy van Pelt, NGC 6153 by Ralf Schoofs, NGC 6153 by Matej Novak, NGC 7814 by Gavrila Alexandru, NGC 7026 by Linda Morgan-O’Connor

Credit: NASA & ESA

Judges ranked images from two categories, an image processing category and basic image searching category. Judges sifted through 1189 entries in the image processing category; a painstaking process of finding promising data and creating an attractive image using professional imaging software. But even if contestants didn’t have the technical know-how to create large mosaics and combine color filters, they could find stunning images in the Hubble archive using using simple online tools. The ESA received more than 1600 entries in this category.

“Every week, we search the archive for hidden treasures, process the scientific data into attractive images and publish them as the Hubble Picture of the Week,” says the ESA on their Hidden Treasures website. “But the archive is so vast that nobody really knows the full extent of what Hubble has observed.”

Josh Lake of the United States won with this awesome image of NGC 1763, part of the N11 star-forming region of the Large Magellanic Cloud.

First place in the processed category, which asked contestants to find promising data within the archive and process that scene into an attractive image, went to Josh Lake, from the United States. The image, which won the public vote, narrowly edged out other images. Lake produced a bold two-color image that is not in natural colors but contrasts light from glowing hydrogen and nitrogen. In natural colors, the two glowing gasses produce almost indistinguishable shades of red. Lake’s image separates them out into red and blue offering a dramatic view of the structure.

Messier 77 produced by Andre van der Hoeven, of the Netherlands came in a close second.

Andre van der Hoeven of the Netherlands came in a close second. The jury noted the impressive nature of Messier 77 in the image as well as the processing which combines several datasets from separate instruments to create the amazing image.

“This was my hardest job until now,” van der Hoeven says on the Flickr page. “Combining the different datasets to get equal colors was really hard. M77 was not fully covered by one dataset, so I had to combine channels of the WFPC2 with different wavelengths and tune the colors to get them to fit. But the result is in my opinion quite astonishing.”

We are as surprised as him that this image had not been released before.

Judy Schmidt of the United States entered this image of XZ Tauri, a new star lighting up a nearby cloud of gas and dust. She entered several images into the contest.

Third place went to an interesting image of XZ Tauri, a newborn star spraying gas into its surroundings as well as lighting up a nearby cloud of gas. The panel said it was a challenging dataset to process because Hubble captured only two colors in the region. “Nevertheless, the end result is an attractive image, and an unusual object that we would never have found without her help,” the panel said.

Revealing the challenge of many Hubble mosaics, the jury was impressed with the technical achievement Renaud Houdinet showed in putting together this ambitious view. He called this “The Great Mosaic Disaster in Chamaeleon. “Sometimes, things don’t turn out as they ought,” Houdinet admits on the Flickr description. Chamaeleon 1 is a large nebula near the south celestial pole and was not covered in one single Hubble image.

Robert Gendler took fifth place with an image of spiral galaxy Messier 96. You may know Gendler’s work as his version of Hubble’s image of NGC 3190 is the default image on the desktop of new Apple computers.

Top image caption: Top ten images selected in the Hubble Hidden Treasures image processing competition. Top row: NGC 1763 by Josh Lake, M 77 by Andre van der Hoeven, XZ Tauri by Judy Schmidt, Chamaeleon I by Renaud Houdinet, M 96 by Robert Gendler. Bottom row: SNR 0519-69 by Claude Cornen, PK 111-2.1 by Josh Barrington, NGC 1501 by kyokugaisha1, Abell 68 by Nick Rose, IC 10 by Nikolaus Sulzenauer. Credit: NASA & ESA

Links:

About the Author: John Williams is owner of TerraZoom, a Colorado-based web development shop specializing in web mapping and online image zooms. He also writes the award-winning blog, StarryCritters, an interactive site devoted to looking at images from NASA’s Great Observatories and other sources in a different way. A former contributing editor for Final Frontier, his work has appeared in the Planetary Society Blog, Air & Space Smithsonian, Astronomy, Earth, MX Developer’s Journal, The Kansas City Star and many other newspapers and magazines.

Posted on by Nancy Atkinson

Star Clusters on a Clandestine Collision Course

Astronomers originally thought that just one massive star cluster shone brightly in a huge star forming region of the Tarantula Nebula, also known as 30 Doradus. But closer analysis using data from the Hubble Space Telescope shows that it is actually two different clusters that are just starting to collide and merge. A team of astronomers led by Elena Sabbi of the Space Telescope Science Institute noticed that different stars in the same region were of different ages, by at least one million years. Besides the age differences, the scientists also noticed two distinct regions, with one having the elongated “look” of a merging cluster.

“Stars are supposed to form in clusters,” said Sabbi, “but there are many young stars outside 30 Doradus that could not have formed where they are; they may have been ejected at very high velocity from 30 Doradus itself.”


Sabbi and her team were initially looking for runaway stars — fast-moving stars that have been kicked out of their stellar nurseries where they first formed.

But they noticed something unusual about the cluster when looking at the distribution of the low-mass stars detected by Hubble. It is not spherical, as was expected, but has features somewhat similar to the shape of two merging galaxies where their shapes are elongated by the tidal pull of gravity.

Some models predict that giant gas clouds out of which star clusters form may fragment into smaller pieces. Once these small pieces precipitate stars, they might then interact and merge to become a bigger system. This interaction is what Sabbi and her team think they are observing in 30 Doradus.

There are also an unusually large number of runaway, high-velocity stars around 30 Doradus, and after looking more closely at the clusters, the astronomers believe that these runaway stars were expelled from the core of 30 Doradus as the result of the dynamical interactions between the two star clusters. These interactions are very common during a process called core collapse, in which more-massive stars sink to the center of a cluster by dynamical interactions with lower-mass stars. When many massive stars have reached the core, the core becomes unstable and these massive stars start ejecting each other from the cluster.

The big cluster R136 in the center of the 30 Doradus region is too young to have already experienced a core collapse. However, since in smaller systems the core collapse is much faster, the large number of runaway stars that has been found in the 30 Doradus region can be better explained if a small cluster has merged into R136.

The entire 30 Doradus complex has been an active star-forming region for 25 million years, and it is currently unknown how much longer this region can continue creating new stars. Smaller systems that merge into larger ones could help to explain the origin of some of the largest known star clusters, Sabbi and her team said.

Follow-up studies will look at the area in more detail and on a larger scale to see if any more clusters might be interacting with the ones observed. In particular the infrared sensitivity of NASA’s planned James Webb Space Telescope (JWST) will allow astronomers to look deep into the regions of the Tarantula Nebula that are obscured in visible-light photographs. In these areas cooler and dimmer stars are hidden from view inside cocoons of dust. Webb will better reveal the underlying population of stars in the nebula.

The 30 Doradus Nebula is particularly interesting to astronomers because it is a good example of how star-forming regions in the young universe may have looked. This discovery could help scientists understand the details of cluster formation and how stars formed in the early Universe.

Science Paper by: E. Sabbi, et al. (ApJL, 2012) (PDF document)

Source: HubbleSite

Posted on by Nancy Atkinson

Inspiring Video: The Biological Advantage of Being Awestruck

How many times a week do we use the word “awesome” here on Universe Today? While we haven’t kept track, we admit it’s quite often. We feel privileged to be able to share with you the incredible — yes, awesome — images, videos and stories of our exploration of space. And it turns out, being awestruck could actually be good for us.

“Our ability to awe was biologically selected for us by evolution because it imbues our lives with a sense of cosmic significance that has resulted in a species that works harder not just to survive but to flourish and thrive,” writes filmmaker Jason Silva, who has produced this awesome new video about being awestruck.

Based on three different researcher’s work, Silva’s film highlights how having regular experiences of awe makes us feel good, provides a reason to live and love, spurs us to keep exploring and pushing onward, and provides an “unprecedented expansion of human vision.” The video shows many images from space, especially pictures produced by the Hubble Space Telescope, and Silva told Universe Today that this video is actually dedicated to the HST.

Sit back and enjoy the wonder of being awestruck!

Caption: A firestorm of star birth in the active galaxy Centaurus A. Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration

The Biological Advantage of Being Awestruck – by @Jason_Silva from Jason Silva on Vimeo.