galaxies | Universe Today

Looking at a galaxy edge-on provides astronomers the opportunity to study different aspects of galaxies than a face-on view offers. This Hubble image of NGC 4710 is part of a survey conducted to provide more information about the puzzling bulges that form around the middle of some galaxies. Have these galaxies been "eating" too much, or is it just part of a "middle-age spread" similar to what humans experience? Astronomers aren't sure why bulges evolve and become a substantial component of most spiral galaxies.
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We regularly report on the discovery of extrasolar planets in our galaxy, but earlier this year came news of possibly the first planet discovered outside of the Milky Way. Now comes news of the potential discovery of dozens of extragalactic planetary systems. Erin Mentuch and her colleagues at the University of Toronto in Canada have analyzed 88 remote galaxies and found a broad continuum excess in the near-infrared. They conclude the most likely explanation for the 2-5 micron excess is the light from circumstellar disks, or young solar systems, forming around massive young stars. "[This] presents us with an exciting opportunity to measure the formation rate of planetary systems at cosmic epochs before our own Solar System formed," the team writes in their paper.
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This 3D illustration shows the position of the galaxies and reveals the extent of this gigantic structure. The galaxies located in the newly discovered structure are shown in red. Galaxies that are either in front or behind the structure are shown in blue. Credit: ESO

Are there "skeletons" out in the Universe –structures that form the framework of how galaxies are distributed? Astronomers have tracked down a gigantic, previously unknown assembly of galaxies located almost seven billion light-years away from us, which seems to point to a prominent galaxy structure in the distant Universe, providing further insight into the cosmic web and how it formed. “Matter is not distributed uniformly in the Universe,” says Masayuki Tanaka from ESO, who led the new study. “In our cosmic vicinity, stars form in galaxies and galaxies usually form groups and clusters of galaxies. The most widely accepted cosmological theories predict that matter also clumps on a larger scale in the so-called ‘cosmic web’, in which galaxies, embedded in filaments stretching between voids, create a gigantic wispy structure.”
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What accelerates cosmic rays to nearly the speed of light? Astronomer have pondered that question for nearly 100 years, and now new evidence supports a theory held for two decades that cosmic rays likely are powered by exploding stars and stellar winds. "This discovery has been predicted for almost 20 years, but until now no instrument was sensitive enough to see it," said Wystan Benbow, an astrophysicist at the Smithsonian Astrophysical Observatory who coordinated this project for the Very Energetic Radiation Imaging Telescope Array System (VERITAS) collaboration.
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A galaxy cluster located about 10.2 billion light years from Earth has been discovered by combining data from NASA's Chandra X-ray Observatory with optical and infrared telescopes. The cluster, JKCS041, is the most distant galaxy cluster yet observed, and we see it as when the Universe was only about a quarter of its present age. The cluster's distance beats the previous record holder by about a billion light years.
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By galactic standards, Barnard is a misfit. This galaxy is diminutive, oddly shaped, and hard to see. But give the little box-shaped guy credit: this dwarf galaxy has no shortage of stellar splendor and pyrotechnics. Some feisty star formation is taking place, and a few curious nebulae dot the landscape with scorching stars sending waves of matter smashing into the surrounding stellar material. Plus, Barnard has a storied past: it likely was the victim of cannibalization. But cosmic misfits like Barnard's Galaxy help researchers understand how galaxies interact, evolve and occasionally feed on each other, leaving behind radiant, star-filled scraps.
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At first glance, this latest image release from Hubble appears to be one really bizarre-looking galaxy. But actually, this is a pair of spiral galaxies that resemble our own Milky Way smashing together at breakneck speeds. The centers have already merged into one nucleus, and the two tidal tails stretching out from the center are sparkling with active star formation, prompted by the exchange of mass and gases from the dramatic collision. This object, NGC 2623, or Arp 243, is about 250 million light-years away in the constellation of Cancer (the Crab), and is in the late stages of the merging process.
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Strange forces of nature are stripping away gas from galaxies in the Virgo cluster. An extremely hot X-ray emitting gas known as the intra-cluster medium permeates the regions between galaxies inside clusters and, as fast moving galaxies whip through this medium, strong winds tear through galaxies distorting their shape and even halting star formation with a process known as "ram pressure stripping." Hubble spied two galaxies "losing it" to these forces.
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Normally, the Swift satellite is searching for distant cosmic explosions. But recently it took some time to take a long look (total exposure time: 24 hours) with its ultraviolet eyes at the Andromeda galaxy, a.k.a. M31. The result is this gorgeous image. "Swift reveals about 20,000 ultraviolet sources in M31, especially hot, young stars and dense star clusters," said Stefan Immler, a research scientist on the Swift team at NASA's Goddard Space Flight Center. "Of particular importance is that we have covered the galaxy in three ultraviolet filters. That will let us study M31's star-formation processes in much greater detail than previously possible."

Compare this image to an optical version taken by a ground-based telescope:
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Unfortunately, the Universe isn't equipped with any three-panel dressing room mirrors, so we can't see what our own Milky Way Galaxy looks like face on, or even from the side. But here's a great new edge-on image of Galaxy NGC 4945, and many astronomers think this hive of stars closely resembles our own spiral galaxy with swirling, luminous arms and a bar-shaped central region. However, in sizing up this mirror-like image, does our black hole look that big? No, say astronomers from the European Southern Observatory. NGC 4945 has a brighter center that is likely home to a supermassive black hole bigger than the Milky Way's, and it is devouring reams of matter and blasting energy out into space.
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A long time ago in a galaxy far, far away there was a supermassive black hole….. Astronomers from the University of Hawaii have spotted a giant galaxy surrounding the most distant supermassive black hole ever found. The galaxy, so distant that it is seen as it was 12.8 billion years ago, is as large as the Milky Way galaxy and harbors a supermassive black hole that contains at least a billion times as much matter as our Sun.
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We humans like to coddle and cuddle our young, protecting them in comfy, quiet nurseries where they will come to no harm. But what kind of treatment do infant planetary systems receive? They get bombarded with powerful winds and blazing heat, and pummeled by short-lived, massive stars that explode as supernovae. New images released today delve into the heart of a cosmic cloud, called RCW 38, crowded with budding stars and planetary systems. Although this is a hostile place, it makes a pretty picture, and new solar systems are in the process of forming in the same kind of environment from which our home may have evolved.
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We all know youngsters are a handful, but this really takes the cake: astronomers have clocked the speeds of stars in infant galaxies at about a million miles an hour, about twice the pace of our Sun's cruise through the Milky Way.

The small galaxies date to 11 billion years ago, when the universe was just a couple billion years old. Their stars, astronomers say, are buzzing and whirling at head-spinning rates.

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Astronomers think that there are hundreds of billions galaxies in the universe, however the exact number is not known. But astronomers should know how many galaxies we've actually seen and discovered, right? Well, not necessarily. “We don’t know,” says Ed Churchwell, professor of astronomy at the University of Wisconsin-Madison. “We know it’s a very large number.” In just one image for example, the Hubble Ultra Deep Field, above, there are about 10,000 galaxies visible.
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What is small, mysterious, faint, in the process of losing mass, and can dance like crazy? Could it be Marie Osmond? Well, that might be the correct answer in this galaxy, but just on the outskirts of the Milky Way are small, mysterious galaxies called dwarf spheroidal galaxies, and a new study offers an explanation for the origin of these puzzling objects. But can they really dance? Yes, says lead author Elena D'Onghia of the Harvard-Smithsonian Center for Astrophysics.
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