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

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

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”

Can You Find a Hubble Hidden Treasure?


Just look at the kind of stunning images that are buried in the archives from the Hubble Space Telescope! Here, Hubble turned its powerful wide field Advanced Camera for Surveys towards this spiral galaxy and took this close-up of its northern half. The entire galaxy, called NGC 891, stretches across 100,000 light-years and we see it exactly edge-on. Visible are filaments of dust and gas escaping the plane of the galaxy. A few foreground stars from the Milky Way shine brightly in the image, while distant elliptical galaxies can be seen in the lower right of the image.

This is just an example of the hidden gems in Hubble’s archives that have never been seen by the general public. There’s a new contest to find more — so how can you participate?

The HST has made over one million observations during its more than two decades in orbit. New images are published nearly every week, but hidden in Hubble’s huge data archives are some truly breathtaking images that have never been seen. They’re called Hubble’s Hidden Treasures, and between now and May 31, 2012, ESA invites you to help bring them to light. Just explore the Hubble Legacy Archive (HLA), and dig out a great dataset, adjust the contrast and colors using the simple online tools, and submit to the Hubble’s Hidden Treasures Contest Flickr group. For more information about the competition, visit the Hubble’s Hidden Treasures webpage.

The European Southern Observatory (ESO) also conducted a similar ‘treasure hunt’ with great results

This image was found by contestant Nick Rose.

A Star-Making Blob from the Cosmic Dawn


Looking back in time with some of our best telescopes, astronomers have found one of the most distant and oldest galaxies. The big surprise about this blob-shaped galaxy, named GN-108036, is how exceptionally bright it is, even though its light has taken 12.9 billion years to reach us. This means that back in its heyday – which astronomers estimate at about 750 million years after the Big Bang — it was generating an exceptionally large amount of stars in the “cosmic dawn,” the early days of the Universe.

“The high rate of star formation found for GN-108036 implies that it was rapidly building up its mass some 750 million years after the Big Bang, when the Universe was only about five percent of its present age,” said Bahram Mobasher, from the University of California, Riverside. “This was therefore a likely ancestor of massive and evolved galaxies seen today.”

An international team of astronomers, led by Masami Ouchi of the University of Tokyo, Japan, first identified the remote galaxy after scanning a large patch of sky with the Subaru Telescope atop Mauna Kea in Hawaii. Its great distance was then confirmed with the W.M. Keck Observatory, also on Mauna Kea. Then, infrared observations from the Spitzer and Hubble space telescopes were crucial for measuring the galaxy’s star-formation activity.

“We checked our results on three different occasions over two years, and each time confirmed the previous measurement,” said Yoshiaki Ono, also from the of the University of Tokyo.

Astronomers were surprised to see such a large burst of star formation because the galaxy is so small and from such an early cosmic era. Back when galaxies were first forming, in the first few hundreds of millions of years after the Big Bang, they were much smaller than they are today, having yet to bulk up in mass.

The team says the galaxy’s star production rate is equivalent to about 100 suns per year. For reference, our Milky Way galaxy is about five times larger and 100 times more massive than GN-108036, but makes roughly 30 times fewer stars per year.

Astronomers refer to the object’s distance by a number called its “redshift,” which relates to how much its light has stretched to longer, redder wavelengths due to the expansion of the universe. Objects with larger redshifts are farther away and are seen further back in time. GN-108036 has a redshift of 7.2. Only a handful of galaxies have confirmed redshifts greater than 7, and only two of these have been reported to be more distant than GN-108036.

About 380,000 years after the Big Bang, a decrease in the temperature of the Universe caused hydrogen atoms to permeate the cosmos and form a thick fog that was opaque to ultraviolet light, creating what astronomers call the cosmic dark ages.

“It ended when gas clouds of neutral hydrogen collapsed to generate stars, forming the first galaxies, which probably radiated high-energy photons and reionized the Universe,” Mobasher said. “Vigorous galaxies like GN-108036 may well have contributed to the reionization process, which is responsible for the transparency of the Universe today.”

“The discovery is surprising because previous surveys had not found galaxies this bright so early in the history of the universe,” said Mark Dickinson of the National Optical Astronomy Observatory in Tucson, Ariz. “Perhaps those surveys were just too small to find galaxies like GN-108036. It may be a special, rare object that we just happened to catch during an extreme burst of star formation.”

Sources: Science Paper by: Y. Ono et al., Subaru , Spitzer Hubble

Space Spectacular — Rotation Movies of Vesta

Take us into orbit Mr. Sulu!

The Dawn science team has released two spectacular rotation movies of the entire globe of the giant asteroid Vesta. The flyover videos give the distinct impression that you are standing on the bridge of the Starship Enterprise and gazing at the view screen as the ship enters orbit about a new planet for the first time and are about to begin an exciting new journey of exploration and discovery of the body you’re looking at below.

Thanks to NASA, DLR, ASI and Dawn’s international science and engineering team, we can all join the away team on the expedition to unveil Vesta’s alluring secrets.

Click the start button and watch protoplanet Vesta’s striking surface moving beneath from the perspective of Dawn flying above – in the initial survey orbit at an altitude of 2700 kilometers (1700 miles). Vesta is the second most massive object in the main asteroid belt and Dawn’s first scientific conquest.

Another video below was compiled from images taken earlier on July 24, 2011 from a higher altitude after Dawn first achieved orbit about Vesta and revealed that the northern and southern hemispheres are totally different.

The array of images in the videos was snapped by Dawn’s framing camera which was provided by the German Aerospace Center (DLR). The team then created a shape model from the images, according to Dr. Carol Raymond, Dawn’s Deputy Principal Investigator from NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

The shape model will aid in studying Vesta’s strikingly diverse features of mountains, ridges, valley’s, scarps, cliffs, grooves, craters, even a ‘snowman’ and much more.

Notice that not all of Vesta is illuminated – because it’s northern winter at the asteroid. Vesta has seasons like Earth and the northern polar region in now in perpetual darkness. Data is collected over the day side and radioed back to Earth over the night side.

“On Vesta right now, the southern hemisphere is facing the sun, so everywhere between about 52 degrees north latitude and the north pole is in a long night,” says Dr. Rayman, Dawn’s Chief Engineer from JPL. “That ten percent of the surface is presently impossible to see. Because Dawn will stay in orbit around Vesta as together they travel around the sun, in 2012 it will be able to see some of this hidden scenery as the seasons advance.”

Another movie highlight is a thorough look at the gigantic south pole impact basin. The circular feature is several hundred miles wide and may have been created by a cosmic collision eons ago that excavated massive quantities of material and basically left Vesta lacking a south pole.


The massive feature was discovered in images taken by the Hubble Space Telescope several years ago and mission scientists have been eager to study it up close in a way that’s only possible from orbit. Dawn’s three science instruments will investigate the south pole depression in detail by collecting high resolution images and spectra which may reveal the interior composition of Vesta.

Dawn entered the survey orbit on Aug. 11 and completed seven revolutions of 69 hours each on Sept. 1. It transmitted more than 2,800 pictures from the DLR framing camera covering the entire illuminated surface and also collected over three million visible and infrared spectra from the VIR spectrometer – provided by ASI, the Italian Space Agency. This results exceeded the mission objectives.

The Dawn spacecraft is now spiraling down closer using its ion propulsion system to the next mapping orbit – known as HAMO – four times closer than the survey orbit and only some 680 km (420 miles) above the surface.

Read Ken’s continuing features about Dawn
3 D Alien Snowman Graces Vesta
NASA Unveils Thrilling First Full Frame Images of Vesta from Dawn
Dawn Spirals Down Closer to Vesta’s South Pole Impact Basin
First Ever Vesta Vistas from Orbit – in 2D and 3D
Dawn Exceeds Wildest Expectations as First Ever Spacecraft to Orbit a Protoplanet – Vesta
Dawn Closing in on Asteroid Vesta as Views Exceed Hubble
Dawn Begins Approach to Asteroid Vesta and Snaps First Images
Revolutionary Dawn Closing in on Asteroid Vesta with Opened Eyes

Hubble’s Birthday Gift to Us: Mystic Mountain


Happy 20th Birthday to the Hubble Space Telescope! While we should be showering HST with gifts, instead the telescope provides this present to us: an amazing view of what has been nicknamed “Mystic Mountain. ” It is just a small portion of one of the largest known star-birth regions in the galaxy, the Carina Nebula. Three light-year-tall towers of cool hydrogen laced with dust rise from the wall of the nebula. The scene is reminiscent of Hubble’s classic “Pillars of Creation” photo from 1995, but even more striking. “Mystic Mountain has clouds of gas and dust, that have not only baby stars, but also baby solar systems,” said John Grunsfeld, Hubble-hugger, repairman and now the Deputry Director of the Space Telescope Science Institute. “4.5 billion years ago, this may be what our solar system looked like.”

Would you like to wish Hubble a happy birthday?

Hubble fans worldwide are being invited to take an interactive journey with Hubble. They can also visit Hubble Site to share the ways the telescope has affected them. Follow the “Messages to Hubble” link to send an e-mail, post a Facebook message, or send a cell phone text message. Fan messages will be stored in the Hubble data archive along with the telescope’s science data. For those who use Twitter, you can follow @HubbleTelescope or post tweets using the Twitter hashtag #hst20.

These two images of a three-light-year-high pillar of star birth demonstrate how observations taken in visible and infrared light by NASA's Hubble Space Telescope reveal dramatically different and complementary views of an object. Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI) › Larger image

Hubble launched on April 24, 1990.

“Hubble is undoubtedly one of the most recognized and successful scientific projects in history,” said Ed Weiler, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “Last year’s space shuttle servicing mission left the observatory operating at peak capacity, giving it a new beginning for scientific achievements that impact our society.”

This morning during interviews on NASA TV, Grunsfeld and Weiler said they both felt fortunate to work with Hubble, a telescope who’s legacy will live on, no matter how much longer the telescope operates.

“I’m lucky to have worked on a project that will outlive me,” Weiler said.

“The discovery that I think is so incredible, and could not be imaged was that Hubble has now analyzed the constituents of an atmosphere of a planet around another star,” said Grunsfeld. “It is as if we were exploring that planet – and that’s what Hubble does for us, allows us to visit places we’ll never be able to go.”

On that note, take a 3-D trip into the Carina Nebula with the video below:

Hubble Captures Birth, Annihilation of Young Solar Systems in Orion Nebula

Looking deep inside the Orion Nebula, the Hubble Space Telescope has captured a stunning collection of protoplanetary disks – or proplyds – which are embryonic solar systems in the making. Using Hubble’s Advanced Camera for Surveys (ACS), researchers have discovered 42 protoplanetary blobs, which are being illuminated by a bright star cluster. These disks, which sometimes appear like boomerangs, arrows, or space jellyfish, surround baby stars and are shedding light on the mechanism behind planet formation.

One of 42 new proplyds discovered in the Orion Nebula, 181-825 is one of the bright proplyds that lies relatively close to the nebula’s brightest star, Theta 1 Orionis C. Resembling a tiny jellyfish, this proplyd is surrounded by a shock wave that is caused by stellar wind from the massive Theta 1 Orionis C interacting with gas in the nebula.  Credit: NASA/ESA and L. Ricci (ESO)
One of 42 new proplyds discovered in the Orion Nebula, 181-825 is one of the bright proplyds that lies relatively close to the nebula’s brightest star, Theta 1 Orionis C. It resembles a tiny jellyfish. Credit: NASA/ESA and L. Ricci (ESO)

As newborn stars emerge from the nebula’s mixture of gas and dust, proplyds form around them. The center of the spinning disc heats up and becomes a new star, but remnants around the outskirts of the disc attract other bits of dust and clump together. This is the beginning of a solar system.

But not all proplyds face a bright and happy future, even in these beautiful images.

Bright star that illuminates some of the proplyds is both a blessing and a curse. The disks that lie close to the brightest star in the cluster (Theta 1 Orionis C) are being zapped by the star’s powerful emissions. The radiation that lights them up and makes them visible also threatens their very existence. As the disk material begins to heat, it is very likely to dissipate and dissolve, destroying the potential for planets to form. Some of these proplyds will be torn apart; however others will survive and perhaps evolve into planetary systems.

One of 42 new proplyds discovered in the Orion Nebula, 321-602 is one of the dark proplyds that lies relatively far from the nebula’s brightest star, Theta 1 Orionis C.  Credit: NASA/ESA and L. Ricci (ESO)
One of 42 new proplyds discovered in the Orion Nebula, 321-602 is one of the dark proplyds that lies relatively far from the nebula’s brightest star, Theta 1 Orionis C. Credit: NASA/ESA and L. Ricci (ESO)

Discs that are farther away do not receive enough energetic radiation from the star to heat up the gas and so they can only be detected as dark silhouettes against the background of the bright nebula, as the dust that surrounds these discs absorbs background visible light. By studying these silhouetted discs, astronomers are better able to characterize the properties of the dust grains that are thought to bind together and possibly form planets like our own.

A montage of 30 proplyds in the Orion Nebula.  Credit: NASA/ESA and L. Ricci (ESO
A montage of 30 proplyds in the Orion Nebula. Credit: NASA/ESA and L. Ricci (ESO

The brighter discs are indicated by a glowing cusp in the excited material and facing the bright star, but which we see at a random orientation within the nebula, so some appear edge on, and others face on, for instance. Other interesting features enhance the look of these captivating objects, such as emerging jets of matter and shock waves.

It is rare to see proplyds in visible light, but the astronomers were able to use Hubble for this ambitious survey of the familiar and photogenic Orion Nebula.

Source: ESA