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  • richardmitnick 10:54 am on January 4, 2017 Permalink | Reply
    Tags: Blue Ring Around an Ancient Red Core, , Exotic Double-Ring Galaxy Unlike Any Observed Before, U Minnesota   

    From U Minnesota via Daily Galaxy: “Exotic Double-Ring Galaxy Unlike Any Observed Before –“Blue Ring Around an Ancient Red Core” 

    u-minnesota-bloc

    University of Minnesota

    1

    Daily Galaxy

    January 04, 2017
    No writer credit

    1
    Image credit: Ryan Beauchemin

    Approximately 359 million light-years away from Earth, there is a galaxy with an innocuous name (PGC 1000714) that doesn’t look quite like anything astronomers have observed before. New research provides a first description of a well-defined elliptical-like core surrounded by two circular rings — a galaxy that appears to belong to a class of rarely observed, Hoag-type galaxies (Hoag’s Bull’s Eye Galaxy 600 million light years away is shown above).
    “Less than 0.1% of all observed galaxies are Hoag-type galaxies,” says Burcin Mutlu-Pakdil, lead author of a paper on this work and a graduate student at the Minnesota Institute for Astrophysics, University of Minnesota Twin Cities and University of Minnesota Duluth. Hoag-type galaxies are round cores surrounded by a circular ring, with nothing visibly connecting them. The majority of observed galaxies are disc-shaped like our own Milky Way. Galaxies with unusual appearances give astronomers unique insights into how galaxies are formed and change.

    The researchers collected multi-waveband images of the galaxy, which is only easily observable in the Southern Hemisphere, using a large diameter telescope in the Chilean mountains. These images were used to determine the ages of the two main features of the galaxy, the outer ring and the central body.

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    While the researchers found a blue and young (0.13 billion years) outer ring, surrounding a red and older (5.5 billion years) central core, they were surprised to uncover evidence for second inner ring around the central body. To document this second ring, researchers took their images and subtracted out a model of the core. This allowed them to observe and measure the obscured, second inner ring structure.

    “We’ve observed galaxies with a blue ring around a central red body before, the most well-known of these is Hoag’s object. However, the unique feature of this galaxy is what appears to be an older diffuse red inner ring,” says Patrick Treuthardt, co-author of the study and an astrophysicist at the North Carolina Museum of Natural Sciences.

    Galaxy rings are regions where stars have formed from colliding gas. “The different colors of the inner and outer ring suggest that this galaxy has experienced two different formation periods,” Mutlu-Pakdil says. “From these initial single snapshots in time, it’s impossible to know how the rings of this particular galaxy were formed.” The researchers say that by accumulating snapshot views of other galaxies like this one astronomers can begin to understand how unusual galaxies are formed and evolve.

    While galaxy shapes can be the product of internal or external environmental interactions, the authors speculate that the outer ring may be the result of this galaxy incorporating portions of a once nearby gas-rich dwarf galaxy. They also say that inferring the history of the older inner ring would require the collection of higher-resolution infrared data.

    “Whenever we find a unique or strange object to study, it challenges our current theories and assumptions about how the Universe works. It usually tells us that we still have a lot to learn,” says Treuthardt.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    u-minnesota-campus-twin-cities

    We are Minnesota’s research university. We change lives—through research, education, and outreach.
    Research

    We seek new knowledge that can change how we all work and live.

    At the University of Minnesota, students do research alongside top professors in all majors.
    Education

    We prepare students to meet the great challenges facing our state, our nation, and our world.

    As a U of M student you’ll engage with your professors and fellow students from the very beginning. And you’ll develop your strengths with beyond-the-classroom experiences.
    Outreach

    We apply our expertise to meet the needs of Minnesota, our nation, and the world.

     
  • richardmitnick 7:06 pm on November 28, 2016 Permalink | Reply
    Tags: , , , Researchers propose low-mass supernova triggered formation of solar system, U Minnesota   

    From U Minnesota: “Researchers propose low-mass supernova triggered formation of solar system” 

    u-minnesota-bloc

    University of Minnesota Twin Cities

    1
    About 4.6 billion years ago, a cloud of gas and dust that eventually formed our solar system was disturbed. The ensuing gravitational collapse formed the proto-Sun with a surrounding disc where the planets were born. That cloud might be similar to some region in this much larger complex of gas and dust about 4,500 light-years away in the constellation Cygnus observed by NASA’s Spitzer Telescope. Image credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA

    A research team led by University of Minnesota School of Physics and Astronomy Professor Yong-Zhong Qian uses new models and evidence from meteorites to show that a low-mass supernova triggered the formation of our solar system.

    The findings are published in the most recent issue of Nature Communications, a leading scientific journal.

    About 4.6 billion years ago, a cloud of gas and dust that eventually formed our solar system was disturbed. The ensuing gravitational collapse formed the proto-Sun with a surrounding disc where the planets were born. A supernova—a star exploding at the end of its life-cycle—would have enough energy to compress such a gas cloud. Yet there was no conclusive evidence to support this theory. In addition, the nature of the triggering supernova remained elusive.

    Qian and his collaborators decided to focus on short-lived nuclei present in the early solar system. Due to their short lifetimes, these nuclei could only have come from the triggering supernova. Their abundances in the early solar system have been inferred from their decay products in meteorites. As the debris from the formation of the solar system, meteorites are comparable to the leftover bricks and mortar in a construction site. They tell us what the solar system is made of and in particular, what short-lived nuclei the triggering supernova provided.

    “This is the forensic evidence we need to help us explain how the solar system was formed,” Qian said. “It points to a low-mass supernova as the trigger.”

    Qian is an expert on the formation of nuclei in supernovae. His previous research has focused on the various mechanisms by which this occurs in supernovae of different masses. His team includes the lead author of the paper, Projjwal Banerjee, who is a former Ph.D. student and postdoctoral research associate, and longtime collaborators Alexander Heger of Monash University, Australia, and Wick Haxton of the University of California, Berkeley. Qian and Banerjee realized that previous efforts in studying the formation of the solar system were focused on a high-mass supernova trigger, which would have left behind a set of nuclear fingerprints that are not present in the meteoric record.

    Qian and his collaborators decided to test whether a low-mass supernova, about 12 times heavier than our sun, could explain the meteoritic record. They began their research by examining Beryllium-10, a short-lived nucleus that has 4 protons (hence the fourth element in the periodic table) and 6 neutrons, weighing 10 mass units. This nucleus is widely distributed in meteorites.

    In fact the ubiquity of Beryllium-10 was something of a mystery in and of itself. Many researchers had theorized that spallation—a process where high-energy particles strip away protons or neutrons from a nucleus to form new nuclei—by cosmic rays was responsible for the Beryllium-10 found in meteorites. Qian said that this hypothesis involves many uncertain inputs and presumes that Beryllium-10 cannot be made in supernovae.

    Using new models of supernovae, Qian and his collaborators have shown that Beryllium-10 can be produced by neutrino spallation in supernovae of both low and high masses. However, only a low-mass supernova triggering the formation of the solar system is consistent with the overall meteoritic record.

    “The findings in this paper have opened up a whole new direction in our research,” Qian said. “In addition to explaining the abundance of Beryllium-10, this low-mass supernova model would also explain the short-lived nuclei Calcium-41, Palladium-107, and a few others found in meteorites. What it cannot explain must then be attributed to other sources that require detailed study.”

    Qian said the group would like to examine the remaining mysteries surrounding short-lived nuclei found in meteorites. The first step, however is to further corroborate their theory by looking at Lithium-7 and Boron-11 that are produced along with Beryllium-10 by neutrino spallation in supernovae. Qian said they may examine this in a future paper and urged researchers studying meteorites look at the correlations among these three nuclei with precise measurements.

    The research is funded by the Department of Energy Office of Nuclear Physics. Qian, Banerjee, and Heger are also scientific participants of the Joint Institute for Nuclear Astrophysics-Center for the Evolution of the Elements, a National Science Foundation Physics Frontier Center.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    u-minnesota-campus-twin-cities

    We are Minnesota’s research university. We change lives—through research, education, and outreach.
    Research

    We seek new knowledge that can change how we all work and live.

    At the University of Minnesota, students do research alongside top professors in all majors.
    Education

    We prepare students to meet the great challenges facing our state, our nation, and our world.

    As a U of M student you’ll engage with your professors and fellow students from the very beginning. And you’ll develop your strengths with beyond-the-classroom experiences.
    Outreach

    We apply our expertise to meet the needs of Minnesota, our nation, and the world.

     
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