Front Matter Pages i-xxiii. Pages The dream.
A dream becomes reality. Simulating servicing. Tools of the trade. Behind the scenes. Service Mission 1.
Back Matter Pages One of the things that we have found is that star-forming galaxies at redshift 2 were often rather clumpy, unlike the rather smooth Milky Way and other nearby galaxies. My colleagues and I have been simulating the formation and evolution of galaxies, and our simulations often also look rather clumpy, with giant star-forming regions in their disks.
The clumps occur partly because the galaxies have so much gas in their disks that the disks become gravitationally unstable and break up into clumps of gas that rapidly form stars. We have been comparing the observed and simulated galaxies systematically, and we have been gratified to find that they appear fairly similar in their sizes and shapes, as well as their clumpiness. See the full article here.
Resembling a diamond-encrusted bracelet, a ring of brilliant blue star clusters wraps Astronomers continue to use the Hubble telescope to look deeper and deeper into . But Hubble's sharp vision resolved the features of the icy world. Hubble image of ring galaxy The Lure of the Rings once a normal spiral galaxy in this image from NASA's Hubble Space Telescope (HST).
In late , the Hubble Space Telescope began an ambitious program to map five carefully selected areas of the sky with its sensitive near-infrared camera, the Wide-Field Camera 3. The observations are important for addressing a wide variety of questions, from testing theories for the birth and evolution of galaxies, to refining our understanding of the geometry of the universe. This is a research blog written by people involved in the project. We aim to share some of the excitement of working at the scientific frontier, using one of the greatest telescopes ever built. We will also share some of the trials and tribulations of making the project work, from the complications of planning and scheduling the observations to the challenges of trying to understand the data.
Along the way, we may comment on trends in astronomy or other such topics. The CANDELS observations are designed to search for galaxies within about a billion years of the big bang, study galaxies at cosmic high-noon about 3 billion years after the big bang — when star-formation and black hole growth were at their peak intensity — and discover distant supernovae for refining our understanding of cosmic acceleration.
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Notify me of new posts via email. In the Universe today galaxies come in a variety of different forms, and are classified via a system known as the Hubble Sequence — and it turns out that this sequence was already in place as early as 11 billion years ago. The Hubble Sequence classifies galaxies according to their morphology and star-forming activity, organising them into a cosmic zoo of spiral, elliptical, and irregular shapes with whirling arms, fuzzy haloes and bright central bulges.
Two main types of galaxy are identified in this sequence: elliptical and spiral , with a third type, lenticular , settling somewhere between the two. This accurately describes what we see in the region of space around us, but how does galaxy morphology change as we look further back in time, to when the Universe was very young?
The astronomers used Hubble to look 11 billion years back in time to when the Universe was very young, exploring the anatomy of distant galaxies. While it was known that the Hubble Sequence holds true as far back as around 8 billion years ago, these new observations push a further 2.
Previous studies had also reached into this epoch of the cosmos to study lower-mass galaxies, but none had conclusively also looked at large, mature galaxies like the Milky Way. The new CANDELS observations confirm that all galaxies this far back — big and small alike — fit into the different classifications of the sequence.
The galaxies at these earlier times appear to be split between blue star-forming galaxies with a complex structure — including discs, bulges, and messy clumps — and massive red galaxies that are no longer forming stars, as seen in the nearby Universe. Galaxies as massive as the Milky Way or more are rather rare in the young Universe. This scarcity has prevented previous studies from being able to gather a large enough sample of mature galaxies to properly describe their characteristics.
The Hubble Sequence underpins a lot of what we know about how galaxies form and evolve — finding it to be in place this far back is a significant discovery. See the full article, with more images and explanatory notes here. Right in the centre of this image, two spiral galaxies appear to be suffering a spectacular collision, with a host of stars appearing to flee the scene of the crash in a chaotic stampede. However, this is just a trick of perspective. It is true that two spiral galaxies are colliding, but they are millions of light-years away, far beyond the cloud of blue and red stars near the merging spiral.
This sprinkling of stars is actually an isolated, irregular dwarf galaxy named ESO The dwarf galaxy is actually much more distant than many bright stars in the foreground of the image, which are located much closer to us, in the Milky Way. It is composed of a few billion red and blue stars — a very small number when compared to galaxies like the Milky Way, which is estimated to contain around to billion stars, or the Andromeda Galaxy , which contains a mind-boggling one trillion. AM Release date: 22 April , The sparkling blue ring is , light-years in diameter, making it larger than our entire home galaxy, the Milky Way.
Tanvir University of Leicester , A. The definitive evidence came from Hubble observations in near-infrared light of the fading fireball produced in the aftermath of a short gamma-ray burst GRB. The afterglow reveals for the first time a new kind of stellar blast called a kilonova , an explosion predicted to accompany a short-duration GRB.
A kilonova is about 1, times brighter than a nova, which is caused by the eruption of a white dwarf. Gamma-ray bursts are mysterious flashes of intense high-energy radiation that appear from random directions in space.
Short-duration blasts last at most a few seconds, but they sometimes generate faint afterglows in visible and near-infrared light that continue for several hours or days. The afterglows have helped astronomers determine that GRBs lie in distant galaxies. The cause of short-duration GRBs, however, remains a mystery. The most popular theory is that astronomers are witnessing the energy released as two compact objects crash together.
But, until now, astronomers have not gathered enough strong evidence to prove it, say researchers.
A team of researchers led by Nial Tanvir of the University of Leicester in the United Kingdom has used Hubble to study a recent short-duration burst in near-infrared light. But we only had weak circumstantial evidence that short bursts were produced by the merger of compact objects. This result now appears to provide definitive proof supporting that scenario.
In a recent science paper Jennifer Barnes and Daniel Kasen of the University of California, Berkeley , and the Lawrence Berkeley National Laboratory presented new calculations predicting how kilonovas should look. They predicted that the same hot plasma producing the radiation will also act to block the visible light, causing the gusher of energy from the kilonova to flood out in near-infrared light over several days. So stay tuned for next time! Galaxies like this one are not stars or artifacts, they are just veeeery faint, so faint that even a telescope as powerful as Hubble is stretched to its capabilities to image them.
When you do see such a faint galaxy, please just answer the questions as best you can. It just happens to be smooth and featureless…. Can you see features despite the noise, or is it smooth? Just do your best! This post is the first of a series introducing the new Galaxy Zoo. The second is here , but come back in the next few days for more information about our fabulous new site. The site is stuffed with new galaxies! These brand new, never-seen-before images come from two places:.
The new SDSS images right , drawn from the latest data release, are better and hopefully easier to classify than the old left. These images are now prepared in a slightly different way, in order to highlight subtle details. In , astronauts on Space Shuttle mission STS visited Hubble for a final time and installed an exciting new camera in the telescope. As we peer deeper into the Universe, we look into the past, and since the universe is expanding, the galaxies we see are moving away from us faster and faster. This means that the light that left them gets stretched by the time it reaches us.
Taking infrared images is much harder than optical ones for many reasons, but the most important is that the night sky actually glows in the infrared. We are also introducing Galaxy Zoo Talk , a place where you can post, share, discuss and collect galaxies you find interesting and want to learn more about. You can of course still join us on the Forum , but Talk will make it easier for you to systematically discuss and analyse your galaxies.
Having looked though many images of merging galaxies I found some really amazing ones. The galaxies are not only connected via one spiral arm like M, but they also have a dimmer bridge between their disks. There is a blue trail which appears in the image flowing to the right of the system.
NGC is very bright in the infrared, with about a hundred billion times the luminosity of the Sun. It is located in the constellation Virgo, about million light-years away from Earth. Both are classic spiral galaxies with small bright nuclei, several knotty arms, and arm segments.
In reality, we know that Pluto's diameter must be somewhere in the range of 2,, kilometers about 1,, miles. Far fewer have had their atmospheres studied. I quickly proceeded past the novelty of being able to read The New York Times while most of Manhattan slept, and discovered a way of looking through the "windows" of crewless spacecraft—vessels that have seen Earth dwindle to the size of a pearl, and then a pixel, as they voyaged far beyond any place ever directly observed by human beings. Clearly visible in their weightless tilt, as symmetrical as something made by the most precise of machine tools from the cleanest of mathematical models on the largest lathe in the galaxy, the multiple rings encircling this improbable object redefine what nature is capable of. Already a member?
Both also have a hint of an inner ring. The pair is thought to be a member of the Virgo Galaxy Cluster. The galaxy cluster is part of the Great Wall of clusters and superclusters , the largest known structure in the Universe. The two spiral galaxies are linked by their swirling arms and is located about million light-years away from Earth. The galaxies are visibly interacting with each other via a bridge of dim stars connecting the two galaxies. Both galaxies have supermassive black holes in their centres and are actively forming new stars in their discs.
With the exception of a few foreground stars from our own Milky Way all the objects in this image are galaxies. Many thanks to everyone in the department and Galaxy Zoo who gave me this opportunity and continue to support me through my work.
It is because of their guidance that I was able to present a research poster at the conference this winter and enjoy a whole new experience. The AAS Conference was fascinating, motivating, and overwhelming all at the same time. Starting from am every morning, I listened to various compact minute talks given by various PhD candidates, post-docs, and researchers from around the world. Though I must admit some of the ideas presented went over my head, I learned more and more with each talk I heard.
The midday lunch breaks made up one of my favorite parts of the conference. Yes, the ribs in Texas are good. But no amount of delicious southern cuisine compares to how welcome and at ease I felt with fellow astronomers kind enough to invite me, a newbie sophomore undergraduate, to lunch.
Lunch became my 2-hour my opportunity to talk one-on-one with other researchers and get informed on their work. When my questions ran out, I gladly took the chance to introduce my own research and use their feedback to better prepare for my poster presentation. On Thursday morning, I tacked up my poster in the exhibit hall and stood guard, armed with organized details of my research and cookies as bait.
Let me confess now that I have never been at or in a science fair, but I imagine it must be similar to what I experienced that day. Non-scientist citizens and experts in AGN alike perused my poster and asked questions. Every once in a while I recognized a familiar face: members from my research group, students I had befriended throughout the conference, and fellow researchers I had shared lunch with stopped by to see my poster. Explaining my research to someone who was interested either in my work or the cookies was an immensely rewarding experience.
I felt proud of what I had accomplished and so thankful to the people who helped me do it. The encounters with other people also gave me ideas for future directions I could proceed in. This semester, I plan to continue searching for multiple AGN signatures in grism spectra of clumpy galaxies. My experience at the AAS Conference has inspired me to develop a more systematic search for clumpy galaxies using Galaxy Zoo and explore in more detail the possibility of low redshift galaxies containing multiple AGN.