My heart stirs at these sights of Transcendence and Harmony,
The cosmic winds whisper an elegant Symphony,
I dance with the Stars, enshrouded in Magnificence
I let my soul free, to soak in this Blissfulness
— Leonidas Papadopoulos
Astronomers have revealed the first deep views from the Hubble Frontier Fields project during the recent 223rd meeting of the American Astronomical Society in Washington, D.C.
As previously reported here on AmericaSpace, Hubble Frontiers Fields is a collaborative project utilising all of NASA’s Great Observatories—the Hubble, Spitzer, and Chandra space telescopes—which aims to obtain the deepest-ever views of the distant Universe by utilising a technique called “gravitational lensing” while studying six specific galaxy clusters.
Gravitational lensing can be described as the phenomenon of the bending of light coming from distant, faraway cosmic sources, from the gravity of massive objects that lie in between. The gravity of these intermediate objects bends and refocuses the light of the more distant, background sources, acting like a lens, allowing us to observe distant parts of the Universe that would otherwise be beyond our view. Gravitational lensing, as an effect of the curvature of space-time by gravity, was first described by Einstein’s theory of General Relativity in the early 20th century and was later observed by astronomers in their studies of distant galaxies and galactic clusters.
Video Credit: NASA/ESA and F. Summers, B. Lawton, M. Lussier, G. Bacon, and D. Coe (STScI)
The goal of the Hubble Frontier Fields project is to boost the viewing capabilities of NASA’s Great Observatories by taking advantage of this property of space-time. “The Frontier Fields is an experiment; can we use Hubble’s exquisite image quality and Einstein’s theory of General Relativity to search for the first galaxies?” says Dr. Matt Mountain, director of the Space Telescope Science Institute, which is responsible for the science operations of the Hubble and Kepler space telescopes, as well as the upcoming James Webb Space Telescope, due to launch in 2018. “With the other Great Observatories, we are undertaking an ambitious joint program to use galaxy clusters to explore the first billion years of the universe’s history.”
The first galaxy cluster to be observed was Abell 2744, also known as the Pandora Cluster, located 3.5 billion light-years away at the southern constellation of Sculptor. It is one of the most massive galactic clusters ever observed and is believed to be the result of a series of previous collisions between four smaller clusters. Indeed, its estimated mass is approximately 400 trillion times that of the Sun—a staggering amount. Yet, the visible galaxies and gas seen in Abell 2744 account for only 25 percent of its total mass. The other 75 percent is believed to consist of dark matter—an invisible kind of matter that can only be observed indirectly by the effects of its gravity and is believed to make up 26.8 percent of the Universe’s total mass-energy.
The combined mass of the few hundreds of galaxies that comprise Abell 2744 has revealed the presence of approximately 3,000 more distant objects lying behind the cluster. The gravitational lensing effect of Abell 2744’s mass bent and refocused the light of these distant objects toward our line of sight, which would have otherwise remained invisible. This way, those galaxies appeared to Hubble 10 to 20 times larger and brighter than normal, seen as bright, long blue streaks and smudges around Abell 2744 in the Frontier Field images. Their warped, arc-shaped appearance is a consequence of this bending of light.
These first results from the Hubble Frontier Fields really validate the techniques of its observing campaign. Some of the distant galaxies discovered lying behind Abell 2744 are actually small dwarf galaxies, with the more distant located more than 12 billion light-years away. This means that with this technique, the Hubble Space Telescope could observe galaxies that are three times more distant than Abell 2744 itself, looking back at a time when the Universe was less than 2 billion years old!
In addition to being able to look further back in time using gravitational lensing, the Hubble telescope was able to observe the interior of Abell 2744 in a resolution that was unobtainable to previous studies of the cluster. In fact, Abell 2744 is revealed in such detail in these images that astronomers were able to detect previously unobserved small, dwarf galaxies inside the cluster, with masses as low as 1/1000th that of our own galaxy. Moreover, Hubble was even able to discern the faint light of individual rogue stars inside the cluster that have been stripped away from their galaxies of origin through gravitational interactions!
These first results help to meet some of the additional goals of the Hubble Frontier Fields project as well: probing the presence of dark matter inside Abell 2744. With the ability to obtain such crisp, deep-view images of the cluster’s interior, astronomers could possibly gain a better understanding of the nature of this ever-elusive mystery of astrophysics. “The Frontier Fields is combining the power of nature’s telescopes — these massive clusters of galaxies — with Hubble, to provide the intrinsically deepest yet view of the universe,” said Jennifer M. Lotz, assistant astronomer at the Space Telescope Science Institute, during the recent AAS meeting.
During the three-year duration of the Frontier Fields program, Hubble will observe six massive galaxy clusters in total. As was the case with the Abell 2744 observations, it will use its Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) instruments in parallel, one focused at the galaxy cluster itself, and the other pointed six arc minutes away from it. After six months, following the Earth’s orbit around the Sun, Hubble will be at the opposite side of the sky and the instruments will “swap” targets, producing a more comprehensive and detailed set of observations for the same object in various wavelengths. The first set of pictures of Abell 2744 were obtained during observing sessions that were conducted in November 2013, totaling 67 hours. Hubble will observe Abell 2744 again the following May. In the meantime, Hubble will start observing next week the second galaxy cluster on the Frontier Fields list, the MACSJ 0416.1-240.
“It’s a fabulous demonstration of the synergy between Hubble and Spitzer,” says Pascal Oesch, astronomer with Yale University in New Haven, Conn.
“The Space Age has transformed technology, and our view of our planet and ourselves. For the last half-century, NASA has been at the forefront of the scientific exploration of the cosmos. Let’s keep it there,” remarks Mountain.
Indeed, the recent results coming from the Hubble Frontier Fields program are a testament to the pioneering spirit and the leadership role that have been the hallmark of NASA throughout the agency’s celebrated history of exploration of the Cosmos.
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This is another beautifily article – with a poem, too! – of yours, thanks!
One detail in the photos makes me wonder: I thought the further away a galaxy is, the more redshifted it gets. Usually, they’d be red on the photos. However, on these two photos, most of the small, far away galaxies seem to be blue? Is this because someone photoprocessed the images for some other purpose, or what is going on?
I’ve heard Hubble usually makes 3 separate images in R, G, and B and then they get combined to show the actual colors. I understand they’d sometimes change the colors to explore a feature not seen as good otherwise.
Can you “shed some light” on this? Thanks
Thank you very much for your kind words!
You’re right, the further away from us an object is in the Universe, the more red-shifted its light will appear to us. For many distant cosmic objects, observations can only be made in the infrared for instance, because their light has been ‘streched’ due to the Universe’s expansion towards longer wavelenghts, that make the object not to appear in visible-light photos.
It is a very keen observation on your behalf to wonder about the blue light that the ‘warped’ galaxies emit in the Frontier Fields images. It shows scientific literacy. Well done! Actually, the image is not photoshoped the way one might think. The Hubble images are indeed processed to correct for bad pixels, observational anomalies and other things. You can read more about this process on the Frontier Fields website here. If you want, you can also read the Hubble team’s scientific paper, that explains the whole process in great detail here, though it’s highly technical and more academic.
The bright blue appearance of the background galaxies were part of a different study, which I didn’t include in the article, because I wanted to focus on the initial first results of the Frontier Fields program instead. Indeed, many different scientific studies have already been made and more will come in the future, from the same images. The reason that the warped’ galaxies appear blue, is because of their intense star formation, which astronomers have calculated is approximately up to 50 times more than the star formation in our own Milky Way galaxy! In essence, these galaxies are packed with young, massive and very bright blue and white stars. Additionally, the Frontier Fields images, are composite images in different wavelenghts, from two different cameras onboard Hubble, The bright blue galaxies for instance, were imaged by the Wide Field Camera 3 in ultraviolet light. Furthermore, not all galaxies are located 13 billion light years away. They’re spreaded in space, with distances that range between 4 to 13 billion light-years away from us. Those that are the more distant ones, indeed appear red in color, because of the high redshift of their light. Some of these distant red galaxies have also been spoted in the Frontier Fields image, during a separate scientific study, which you can read about here.
I hope all of these info help!
With kind regards,
What a humbling experience it is to see these images and to think about our position in the Universe. Even more awe-inspiring is that we as a species can even contemplate such enormity! One wonders what the “limits” are to peering back in time? I seem to recall that we could never observe the “big bang” even if we had the theoretical capability to do so. Another gem, Leonidas, that gets your readers to truly appreciate the beauty of the Universe.
Thank you Tom.
Indeed, faraway areas of the Universe that recede from us (due to the Universe’s expansion) at a speed higher than the speed of light, will always be unobservable and unknown to us. Thus, there will always be ‘limits’ to how far in space and how far back in time we will be able to observe, from our vantage point here on Earth. The observable Universe that we can see, is just a part of the whole Universe that exists. You can read a good summary about that, here.
As for the Big Bang, the theory states that it wasn’t something that happened on a specific point in space-time, for there wasn’t a space-time before the Bang Bang, so it’s not something we could search for at a specific place or time.
Yet, who knows what future discoveries will bring forth, ever changing our perceptions about the Universe in the process?
Thanks, Leonidas. Is it also possible that the “Big Bang” is but a series of “big bangs” in a continuous birth/rebirth of the Universe (or multi-verses)? Just wondering.
Yes. Actually there are a number of scientific hypotheses proposed throughout the years, that posit just that: that the Bing Bang that created our Universe, was just one in a series of infinite Big Bangs, or that it might have been caused by the collision of two multiverses. It’s all highly speculative, for not only aren’t any concrete observational evidence for the existence of multiverses (except for the latest Planck results – more on that here), but a small part of the cosmology community is skeptical of the Standard Model of cosmology itself.
You can also watch a good BBC documentary on parallel universes here. I also tried to find a link to another interesting BBC documentary but couldn’t find any.