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  • richardmitnick 5:43 pm on December 4, 2014 Permalink | Reply
    Tags: Arecibo Observatory, , , , , ,   

    From RAS: “Astronomers detect atomic hydrogen emission in galaxies at record breaking distances” 

    Royal Astronomical Society

    Royal Astronomical Society

    Wednesday, 03 December 2014
    Media contact (UK)

    Dr Robert Massey
    Royal Astronomical Society
    Tel: +44 (0)20 7734 3307 x214
    Mob: +44 (0)794 124 8035
    rm@ras.org.uk

    Science contact

    Dr Barbara Catinella
    Australian Research Council Future Fellow
    Centre for Astrophysics & Supercomputing
    Swinburne University of Technology
    Australia
    Tel: +61 3 9214 4918
    bcatinella@swin.edu.au

    Using the world’s largest radio telescope, two astronomers from Swinburne University of Technology in Australia have detected the faint signal emitted by atomic hydrogen gas in galaxies three billion light years from Earth, breaking the previous record distance by 500 million light years. Their results appear in a paper published in the journal Monthly Notices of the Royal Astronomical Society.

    a
    The 305-m Arecibo radio observatory in Puerto Rico, which was used to detect the hydrogen gas in these distant galaxies. Credit: Arecibo Observatory/NAIC.

    Using the 305-m diameter Arecibo radio telescope in Puerto Rico, Dr Barbara Catinella and Dr Luca Cortese measured the hydrogen gas content of nearly 40 galaxies at distances of up to three billion light years. By doing so, the two scientists found a unique population of galaxies hosting huge reservoirs of hydrogen gas, the fuel for forming new stars like our Sun.

    These very gas-rich systems each contain between 20 and 80 billion times the mass of the Sun in atomic gas. Such galaxies are rare, but astronomers believe that they were more common in the past, when the Universe was younger.

    “Atomic hydrogen gas is the fuel out of which new stars are formed, hence it is a crucial component to study if we are to understand how galaxies form and evolve,” study leader Dr Catinella said.

    “Because of the limitations of current instruments, astronomers still know very little about the gas content of galaxies beyond our local neighbourhood.”

    Local Group
    Local Group

    Co-author Dr Luca Cortese said detecting atomic hydrogen emission from distant galaxies is very challenging.

    “The signals are not only weak, but they appear at radio frequencies that are used by communication devices and radars, which generate signals billions of times stronger than the cosmic ones that we are trying to detect.”

    4
    Images of four distant galaxies observed with the Arecibo radio telescope, which have been found to host huge reservoirs of atomic hydrogen gas. Credit: Sloan Digital Sky Survey.Measuring the atomic hydrogen signal emitted by distant galaxies is one of the main scientific drivers behind the billion dollar Square Kilometre Array (SKA) project, for which technology demonstrators like the Australian SKA Pathfinder are under construction. The Arecibo observations give astronomers a glimpse into the population of gas-rich galaxies that will be routinely discovered by these instruments in coming decades.

    Sloan Digital Sky Survey Telescope
    Sloan Digital Sky Survey Telescope

    SKA Square Kilometer Array

    SKA Pathfinder Radio Telescope
    SKA Pathfinder Radio Telescope

    This project started as an experiment to see at what distances astronomers were able to detect the signal from atomic hydrogen in galaxies.

    “The outcome vastly exceeded our initial expectations,” Dr Catinella said.

    “Not only did we detect radio signals emitted by distant galaxies when the Universe was three billion years younger, but their gas reservoirs turned out to be unexpectedly large, about 10 times larger than the mass of hydrogen in our Milky Way. Such a huge amount of fuel will be able to feed star formation in these galaxies for several billion years in the future.”

    Further studies will seek to understand why these galaxies have not yet converted a great part of their gas into stars. The SKA and its pathfinders will be the key to solving this mystery.

    Further information

    The new results are published in B. Catinella & L. Cortese, HIGHz: A Survey of the Most HI-Massive Galaxies at z~0.2, Monthly Notices of the Royal Astronomical Society, in press, published by Oxford University Press (link will go live on 9 December 2014). A preprint is available on the arXiv.

    The research was supported under the Australian Research Council’s Future Fellowship and Discovery funding schemes.

    See the full article here.

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    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

     
  • richardmitnick 3:38 pm on November 15, 2014 Permalink | Reply
    Tags: Arecibo Observatory, , , , , ,   

    From SLATE: “Messages to the Universe: A Short History of Interstellar Communication” 

    SLATE

    slate.com

    Nov. 14 2014
    Ella Morton

    Nov. 16, 2014, marks the 40th anniversary of the Arecibo message, an interstellar communiqué transmitted from the Arecibo radio telescope in Puerto Rico toward Messier 13, a globular cluster of stars located more than 22,000 light-years away.

    ari
    The Arecibo Radio Telescope in Puerto Rico. Photo: H. Schweiker/WIYN and NOAO/AURA/NSF (Public Domain)

    The content of the message was determined by astrophysicist and Search for Extraterrestrial Intelligence (SETI) founder Frank Drake, with a little help from luminaries like Carl Sagan. It used a string of 1,679 binary digits—the idea was that the alien civilization who receives the message will recognize 1,679 as a semiprime number and multiple of 23 and 73.* “Ah,” they will think (in their native language, obviously), “this binary string of unknown origin is intriguing. Let’s lay out the info in a 23-by-73 grid and see what emerges.”

    fd
    Frank Drake

    cs
    Carl Sagan in 1980

    When the ones and zeroes are put into grid form, what results is a pixelated summary of humanity. It contains seven parts. The first part of the message shows the numbers one through 10. Next are the atomic numbers for carbon, hydrogen, oxygen, nitrogen, and phosphorus. A very simple representation of the DNA double helix follows. Then there is a blocky image of a human, a depiction of Earth’s position in the solar system—with Pluto still shown as a planet, a matter that is still up for debate—and an image of the Arecibo telescope that, to a 2014 eye, resembles the Gmail logo.

    am
    The Arecibo message. Image: Arne Nordmann/Creative Commons

    Even if the folks in Messier 13 were to respond promptly to this message, we’d still have to wait at least 43,960 years for their reply. But the Arecibo message was never really intended as genuine interstellar communication—it was chiefly a demonstration of the Arecibo telescope’s might. (The dish was upgraded in 1974, and the three-minute digital transmission, ostensibly sent to an alien civilization, was quite the celebratory attention-getter.)

    Messier 13’s assumed inhabitants may never become our pen pals, but the tantalizing prospect of interstellar communication continues to entice Earthlings. Since the Arecibo message was transmitted into the universe, at least eight other interstellar radio messages have been beamed into the sky—all within the last 15 years.

    In 2001, Russian astronomer Aleksandr Zaitsev and a group of Russian teenagers broadcast a series of transmissions collectively known as the “Teen Age Message.” Targeted at six stars located between 45.9 and 68.5 light-years away, the messages included Russian folk music and works by classical composers such as Beethoven and Vivaldi. All of this music was played on the theremin—Zaitsev referred to the message as the “First Theremin Concert For Extraterrestrials.” Sent from Yevpatoria Planetary Radar in Crimea, the transmission was the first interstellar musical radio message. There have been more: In 2008, NASA sent the Beatles song Across the Universe across the universe, targeting the Northern Star, Polaris.

    team
    “Teen Age Message” being sent into the universe from Crimea in 2001. Photo: Rumlin/Creative Commons

    Yevpatoria 70m dish
    Yevpatoria Planetary Radar

    The question of how best to communicate with extraterrestrials is one of SETI’s ongoing concerns. Earlier this week, the organization held a workshop in California with the title Communicating Across the Cosmos. A common theme was humanity’s self-obsession. In composing interstellar messages, we tend to assume the intended recipients will get what we’re trying to say. But the scientific knowledge and physiology of nonhuman civilizations may be so different to our own that a Beethoven composition or a stick-figure human is totally indecipherable.

    Even the supposedly universal language of mathematics may not be the best lingua franca. During a talk at the SETI conference, Carl DeVito posed a mind-bending question: “Are the natural numbers, 1, 2, 3, 4, … merely creations of the human mind or do they exist independently of us?” You can watch his talk for more, but for the record, here is his own answer: “I think the natural numbers do exist independently of us. The rest of mathematics, however, might not exist anywhere but in our minds.”

    Of the eight interstellar messages sent since 1999, the first to reach its target will be A Message From Earth, which was sent to extrasolar planet Gliese 581 c in October 2008 and is scheduled to arrive in early 2029. The transmission, intended as a digital time capsule, was initiated by now-defunct RDF Digital—a subsidiary of the U.K. production company responsible for the TV show Wife Swap—and Bebo, a social networking website that declared bankruptcy in 2013. The 501 photos and text messages in the transmission were selected by Bebo users via web vote. In about 15 years, the residents of Gliese 581 c, assuming there are any, will receive a deluge of information about faded British pop stars.

    Though each interstellar transmission has varied wildly in tone and content, each reflects a common core message: “We are here. This is us.” Whether they reach other civilizations is almost irrelevant. The chance to sum up humanity to an extraterrestrial audience is an alluring task, and one that allows us to feel absurdly important while inhabiting, as Carl Sagan wrote in Pale Blue Dot, “a lonely speck in the great enveloping cosmic dark.”

    m13
    The heart of Messier 13, target audience for the Arecibo message. Photo: ESA/Hubble and NASA/Public domain

    NASA Hubble Telescope
    NASA Hubble schematic
    NASA/ESA Hubble

    Visit Atlas Obscura for more on Arecibo Observatory.

    *Correction, Nov. 14, 2014: The post originally misstated that 1,679 was a prime number. (Return to the corrected sentence.)

    See the full article here.

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    Slate is a daily magazine on the Web. Founded in 1996, we are a general-interest publication offering analysis and commentary about politics, news, business, technology, and culture. Slate’s strong editorial voice and witty take on current events have been recognized with numerous awards, including the National Magazine Award for General Excellence Online. The site, which is owned by Graham Holdings Company, does not charge for access and is supported by advertising revenues.

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  • richardmitnick 4:14 pm on August 18, 2014 Permalink | Reply
    Tags: Arecibo Observatory, , , , , , ,   

    From Astrobiology: ” SETI Searches Kepler Candidates for Signals of Life” 

    Astrobiology Magazine

    Astrobiology Magazine

    Aug 18, 2014
    Nola Taylor Redd

    A recent search by the Search for Extraterrestrial Intelligence (SETI) studied 86 candidates in the Kepler space observatory’s field for radio signals that could potentially indicate the presence of an intelligent civilization.

    Of course, no radio signals were found, but the search did identify the most promising Kepler objects for wide-band observations using the Green Bank Telescope in West Virginia.

    NRAO GBT
    NRAO Green Bank Telescope

    “The 86 target stars were selected because they hosted planets discovered by [the year] 2011 with properties that could be conducive to the development of life,” said Abhimat Gautam, of the University of California, Berkeley.

    Gautam, who just completed his senior undergratuate year at the University of California, Berkeley and was part of the Berkeley SETI Research Center, presented the results at the 224th summer meeting of the American Astronomical Society in Boston, Massachusetts in June.

    Widening the search

    By 2011, Kepler had revealed 1,235 planetary candidates (as of June 17, 2014, that number stands at 4,254, with 974 of them confirmed as planets). Gautam worked with Andrew Siemion and other scientists of the Berkeley SETI Research Center to select 86 planetary candidates that had surface temperatures between –50 and 100 degrees Celsius (-58 to 212 degrees Fahrenheit), a radius smaller than three times that of Earth, and an orbital period of more than 50 days. Such conditions placed the objects within the habitable zone around their stars, the region where liquid water can exist on the surface and where life might best be able to develop on a planet.

    k11
    Kepler-11, a sun-like star located approximately 2,000 light-years from Earth, hosts six transiting planets that were the target of a search for signals indicating advanced civilizations.

    The Green Bank Telescope (the world’s largest fully steerable radio telescope, located in Green Bank, West Virginia) targeted the parent stars using a wide-band signal. Scientists had performed previous searches of the Kepler field in the narrow-band with no success. Only 5 Hertz (Hz) wide on the radio spectrum, narrowband signals are only known to arise from artificial sources on Earth, Gautam said. The narrowband range is commonly used in SETI searches.

    By switching to wide-band, Gautam hoped for a number of benefits. Wide-band signals cover 2.5 Megahertz (MHz), which is half a billion times wider than previous searches. Increasing the region of the radio spectrum observed means that listening scientists can search for broader signals than those previously observed. The interstellar medium—the gas and dust between stars—can spread the signal out as it travels through the material, causing a delay that could provide a rough estimate of the distance to any detectable source and allowing SETI astronomers to track potential communications back to their origins.

    In addition, a wide-band signal may be more commonly used for intentional signaling, Gautam said.

    “An advanced alien civilization may even use a pulsar for signaling, which can be more easily and effectively detected in a wide-band search.”

    k22
    Located in the habitable zone around a sun-like star, Kepler-22b, shown in this artist’s interpretation, is 2.4 times the size of Earth. Credit: NASA/Ames/JPL-Caltech

    Gautam, who is pursuing a doctorate in astronomy at the University of California, Los Angeles, first took interest in SETI through theSETI@Home project while still in high school. He contacted Dan Werthimer, chief scientist for SETI@Home, in search of available research projects.

    SETI@home screensaver
    SETI @home

    “When UC Berkeley undergraduate students majoring in the physical sciences express an interest in continuing on for a graduate degree in their field, one of the first suggestions they receive is to seek out research opportunities,” SETI’s Andrew Siemion told Astrobiology Magazine in an email.

    Gautam presented the results while he was still an undergraduate student because“it was all his work,” Siemion said.

    “Abhimat [Gautam] was a fantastic member of our research group,” he said.

    Scanning the skies

    The SETI search focused both on active signals deliberately broadcast by a potential civilization, as well as passive signals such as those created by Earth’s television shows and airport radars.

    “We expect intentional, active signals to be brighter and easier to detect than non-intentional, passive signals,” Gautam said.

    With the Green Bank Telescope pointed at each target star, the radio beam would span approximately 4.2 light-years, wide enough to engulf the planetary system, including unknown bodies.

    According to Siemion’s SETI blog, the search also covered a region of the radio spectrum known as the “terrestrial microwave window,” which can travel through both interstellar space and Earth’s atmosphere with little distortion. Within that window, the SETI search covered the “water hole,” a region of the radio spectrum bounded by the two products of water — hydrogen and hydroxyl.

    “Some scientists have suggested that if an extraterrestrial intelligence were to deliberately signal other intelligent beings, they might chose this band,” Siemion wrote.

    The team found no sign of an intelligent civilization. They concluded that less than 1 percent of the stars in the region produce a radio signal greater than 60 times that of the Arecibo radio telescope in Puerto Rico.

    “The Arecibo Planetary Radar is the most powerful radio transmitter on Earth,” Gautam said.

    “This provides a good estimate for calculating estimates of the detectability of Earth-like technology in our search.”

    Arecibo
    Arecibo

    See the full article here.

    NASA

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  • richardmitnick 7:20 am on August 8, 2014 Permalink | Reply
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    From Royal Astronomical Society: “Astronomers find stream of gas – 2.6 million light years long” 

    Royal Astronomical Society

    Royal Astronomical Society

    07 August 2014
    Ruth E. Torres Hernández
    Public Relations Officer
    Arecibo Observatory
    Puerto Rico
    Tel: +1 787 878 2612 x615
    rutorres@suagm.edu

    Yvonne Guadalupe Negrón
    Director- Public Relations Office
    Universidad Metropolitana
    Puerto Rico
    Tel: +1 787 766 1717 x6405, +1 787 242 0806

    Erin Carver
    Media and Communications Manager
    Universities Space Research Association
    United States
    Tel: +1 410 227 7078
    ecarver@usra.edu

    Dr Robert Massey
    Royal Astronomical Society
    Tel: +44 (0)20 7734 3307 / 4582
    Mob: +44 (0)794 124 8035
    rm@ras.org.uk

    Astronomers and students have found a bridge of atomic hydrogen gas 2.6 million light years long between galaxies 500 million light years away. They detected the gas using the William E. Gordon Telescope at the Arecibo Observatory, a radio astronomy facility of the US National Science Foundation sited in Puerto Rico. The team publish their results today in a paper in Monthly Notices of the Royal Astronomical Society.

    Aracibo Observatory
    Arecibo

    bridge
    The bridge of gas (shown in green) stretches from the large galaxy at the bottom left to the group of galaxies at the top. A third nearby galaxy to the right also has a shorter stream of gas attached to it. The three insets show expanded views of the different galaxies and the green circle indicates the Arecibo telescope beam. Credit: Rhys Taylor/Arecibo Galaxy Environment Survey/The Sloan Digital Sky Survey Collaboration.

    The stream of atomic hydrogen gas is the largest known, a million light years longer than a gas tail found in the Virgo Cluster by another Arecibo project a few years ago. Dr Rhys Taylor, a researcher at the Czech Academy of Sciences and lead author of the paper, said “This was totally unexpected. We frequently see gas streams in galaxy clusters, where there are lots of galaxies close together, but to find something this long and not in a cluster is unprecedented.”

    It is not just the length of the stream that is surprising but also the amount of gas found in it. Roberto Rodriguez, a 2014 graduate from the University of Puerto Rico in Humacao who worked on the project as an undergraduate, explained “We normally find gas inside galaxies, but here half of the gas – 15 billion times the mass of the Sun – is in the bridge. That’s far more than in the Milky Way and Andromeda galaxies combined!”

    The team is still investigating the origin of the stream. One notion surmises that the large galaxy at one end of the stream passed close to the group of smaller galaxies at the other end in the past, and that the gas bridge was drawn out as they moved apart. A second notion suggests that the large galaxy plowed straight through the middle of the group, pushing gas out of it. The team plan to use computer simulations to find out which of these ideas can best match the shape of the bridge that is seen with the Arecibo Telescope.

    The project involved three undergraduate researchers: Roberto Rodriguez and Clarissa Vazquez from UPR Humacao, and Hanna Herbst, now a graduate student at the University of Florida. Dr Robert Minchin, a staff astronomer at Arecibo Observatory and the principal investigator on the project, said “Student involvement is very important to us. We are proud to be inspiring the next generation of astronomers, and particularly proud of the involvement of Puerto Rican students.”

    The bridge was found in data taken between 2008 and 2011 for the Arecibo Galaxy Environment Survey (AGES), which is using the power of the Arecibo Telescope to survey a large area of sky with a high level of sensitivity.

    See the full article here.

    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

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