News Article | December 12, 2016
In 2015, the All Sky Automated Survey for SuperNovae (ASAS-SN) detected an event, named ASASSN-15lh, that was recorded as the brightest supernova ever -- and categorised as a superluminous supernova, the explosion of an extremely massive star at the end of its life. It was twice as bright as the previous record holder, and at its peak was 20 times brighter than the total light output of the entire Milky Way. An international team, led by Giorgos Leloudas at the Weizmann Institute of Science, Israel, and the Dark Cosmology Centre, Denmark, has now made additional observations of the distant galaxy, about 4 billion light-years from Earth, where the explosion took place and they have proposed a new explanation for this extraordinary event. "We observed the source for 10 months following the event and have concluded that the explanation is unlikely to lie with an extraordinarily bright supernova. Our results indicate that the event was probably caused by a rapidly spinning supermassive black hole as it destroyed a low-mass star," explains Leloudas. In this scenario, the extreme gravitational forces of a supermassive black hole, located in the centre of the host galaxy, ripped apart a Sun-like star that wandered too close -- a so-called tidal disruption event, something so far only observed about 10 times. In the process, the star was "spaghettified" and shocks in the colliding debris as well as heat generated in accretion led to a burst of light. This gave the event the appearance of a very bright supernova explosion, even though the star would not have become a supernova on its own as it did not have enough mass. The team based their new conclusions on observations from a selection of telescopes, both on the ground and in space. Among them was the Very Large Telescope at ESO's Paranal Observatory, the New Technology Telescope at ESO's La Silla Observatory and the NASA/ESA Hubble Space Telescope . The observations with the NTT were made as part of the Public ESO Spectroscopic Survey of Transient Objects (PESSTO). "There are several independent aspects to the observations that suggest that this event was indeed a tidal disruption and not a superluminous supernova," explains coauthor Morgan Fraser from the University of Cambridge, UK (now at University College Dublin, Ireland). In particular, the data revealed that the event went through three distinct phases over the 10 months of follow-up observations. These data overall more closely resemble what is expected for a tidal disruption than a superluminous supernova. An observed re-brightening in ultraviolet light as well as a temperature increase further reduce the likelihood of a supernova event. Furthermore, the location of the event -- a red, massive and passive galaxy -- is not the usual home for a superluminous supernova explosion, which normally occur in blue, star-forming dwarf galaxies. Although the team say a supernova source is therefore very unlikely, they accept that a classical tidal disruption event would not be an adequate explanation for the event either. Team member Nicholas Stone from Columbia University, USA, elaborates: "The tidal disruption event we propose cannot be explained with a non-spinning supermassive black hole. We argue that ASASSN-15lh was a tidal disruption event arising from a very particular kind of black hole." The mass of the host galaxy implies that the supermassive black hole at its centre has a mass of at least 100 million times that of the Sun. A black hole of this mass would normally be unable to disrupt stars outside of its event horizon -- the boundary within which nothing is able to escape its gravitational pull. However, if the black hole is a particular kind that happens to be rapidly spinning -- a so-called Kerr black hole -- the situation changes and this limit no longer applies. "Even with all the collected data we cannot say with 100% certainty that the ASASSN-15lh event was a tidal disruption event," concludes Leloudas. "But it is by far the most likely explanation."  As well as the data from ESO's Very Large Telescope, the New Technology Telescope and the NASA/ESA Hubble Space Telescope the team used observations from NASA's Swift telescope, the Las Cumbres Observatory Global Telescope (LCOGT), the Australia Telescope Compact Array, ESA's XMM-Newton, the Wide-Field Spectrograph (WiFeS and the Magellan Telescope. This research was presented in a paper entitled "The Superluminous Transient ASASSN-15lh as a Tidal Disruption Event from a Kerr Black Hole", by G. Leloudas et al. to appear in the new Nature Astronomy magazine. The team is composed of G. Leloudas (Weizmann Institute of Science, Rehovot, Israel; Niels Bohr Institute, Copenhagen, Denmark), M. Fraser (University of Cambridge, Cambridge, UK), N. C. Stone (Columbia University, New York, USA), S. van Velzen (The Johns Hopkins University, Baltimore, USA), P. G. Jonker (Netherlands Institute for Space Research, Utrecht, the Netherlands; Radboud University Nijmegen, Nijmegen, the Netherlands), I. Arcavi (Las Cumbres Observatory Global Telescope Network, Goleta, USA; University of California, Santa Barbara, USA), C. Fremling (Stockholm University, Stockholm, Sweden), J. R. Maund (University of Sheffield, Sheffield, UK), S. J. Smartt (Queen's University Belfast, Belfast, UK), T. Krühler (Max-Planck-Institut für extraterrestrische Physik, Garching b. München, Germany), J. C. A. Miller-Jones (ICRAR - Curtin University, Perth, Australia), P. M. Vreeswijk (Weizmann Institute of Science, Rehovot, Israel), A. Gal-Yam (Weizmann Institute of Science, Rehovot, Israel), P. A. Mazzali (Liverpool John Moores University, Liverpool, UK; Max-Planck-Institut für Astrophysik, Garching b. München, Germany), A. De Cia (European Southern Observatory, Garching b. München, Germany), D. A. Howell (Las Cumbres Observatory Global Telescope Network, Goleta, USA; University of California Santa Barbara, Santa Barbara, USA), C. Inserra (Queen's University Belfast, Belfast, UK), F. Patat (European Southern Observatory, Garching b. München, Germany), A. de Ugarte Postigo (Instituto de Astrofisica de Andalucia, Granada, Spain; Niels Bohr Institute, Copenhagen, Denmark), O. Yaron (Weizmann Institute of Science, Rehovot, Israel), C. Ashall (Liverpool John Moores University, Liverpool, UK), I. Bar (Weizmann Institute of Science, Rehovot, Israel), H. Campbell (University of Cambridge, Cambridge, UK; University of Surrey, Guildford, UK), T.-W. Chen (Max-Planck-Institut für extraterrestrische Physik, Garching b. München, Germany), M. Childress (University of Southampton, Southampton, UK), N. Elias-Rosa (Osservatoria Astronomico di Padova, Padova, Italy), J. Harmanen (University of Turku, Piikkiö, Finland), G. Hosseinzadeh (Las Cumbres Observatory Global Telescope Network, Goleta, USA; University of California Santa Barbara, Santa Barbara, USA), J. Johansson (Weizmann Institute of Science, Rehovot, Israel), T. Kangas (University of Turku, Piikkiö, Finland), E. Kankare (Queen's University Belfast, Belfast, UK), S. Kim (Pontificia Universidad Católica de Chile, Santiago, Chile), H. Kuncarayakti (Millennium Institute of Astrophysics, Santiago, Chile; Universidad de Chile, Santiago, Chile), J. Lyman (University of Warwick, Coventry, UK), M. R. Magee (Queen's University Belfast, Belfast, UK), K. Maguire (Queen's University Belfast, Belfast, UK), D. Malesani (University of Copenhagen, Copenhagen, Denmark; DTU Space, Denmark), S. Mattila (University of Turku, Piikkiö, Finland; Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Piikkiö, Finland; University of Cambridge, Cambridge, UK), C. V. McCully (Las Cumbres Observatory Global Telescope Network, Goleta, USA; University of California Santa Barbara, Santa Barbara, USA), M. Nicholl (Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA), S. Prentice (Liverpool John Moores University, Liverpool, UK), C. Romero-Ca[ñ] - https:/ izales (Pontificia Universidad Católica de Chile, Santiago, Chile; Millennium Institute of Astrophysics, Santiago, Chile), S. Schulze (Pontificia Universidad Católica de Chile, Santiago, Chile; Millennium Institute of Astrophysics, Santiago, Chile), K. W. Smith (Queen's University Belfast, Belfast, UK), J. Sollerman (Stockholm University, Stockholm, Sweden), M. Sullivan (University of Southampton, Southampton, UK), B. E. Tucker (Australian National University, Canberra, Australia; ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia), S. Valenti (University of California, Davis, USA), J. C. Wheeler (University of Texas at Austin, Austin, USA), and D. R. Young (Queen's University Belfast, Belfast, UK). ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become "the world's biggest eye on the sky".
News Article | November 18, 2016
Flash Physics is our daily pick of the latest need-to-know developments from the global physics community selected by Physics World's team of editors and reporters The first optical clock to be operated in space has been launched by Matthias Lezius and colleagues at the Germany-based Menlo Systems. Based on a frequency-comb laser system, the optical clock operates at a frequency that is about 100,000 times higher than that of the microwave-based atomic clocks that are currently used on global-positioning-system (GPS) satellites. The optical clock is about 22 cm in size and weighs 22 kg. Its power consumption is about 70 W, which makes it suitable for satellite applications. Although this prototype optical clock can only operate at about one tenth the accuracy of today's GPS atomic clocks, Lezius' team is now working on a new version of the clock that promises to improve this accuracy by several orders of magnitude – which could boost the accuracy of GPS. The current clock was tested on board a research rocket that flew a 6 min parabolic flight. The next version of the optical clock is scheduled for testing in 2017. The research is described in Optica. The physicist and advocate of strategic nuclear-arms reduction Richard Garwin will receive a Presidential Medal of Freedom from US president Barack Obama. Garwin, who is 88, was a PhD student of Enrico Fermi at the University of Chicago before designing the first hydrogen bomb in 1952 under Edward Teller at Los Alamos National Laboratory. He then moved to IBM's Thomas J Watson Research Center, where he is an IBM fellow emeritus. At IBM he worked on a broad range of topics including condensed matter, particle physics and gravitation. He also applied his skills to the development of touch screens, laser printers and intelligence-gathering technologies. Garwin served as a scientific adviser to presidents Kennedy, Johnson and Nixon, which is when he developed his long-standing interest in nuclear non-proliferation (see video). The medal is the highest civilian honour in the US and it will be given to Garwin and 20 other winners at a ceremony at the White House on 22 November. A brilliant burst of radiation known as a fast radio burst (FRB) that has travelled over a billion light years has unexpectedly revealed information about the cosmic web – the large-scale structure of the universe. A team led by Ryan Shannon at the International Centre for Radio Astronomy Research (ICRAR) and Vikram Ravi of the California Institute of Technology says that the latest FRB – one of 18 to be detected to date – is one of the brightest seen. The flash was captured by CSIRO's Parkes radio telescope in New South Wales, Australia. FRBs are extremely rare, short but intense pulses of radio waves, each only lasting about a millisecond. "This particular FRB is the first detected to date to contain detailed information about the cosmic web – regarded as the fabric of the universe – but it is also unique because its travel path can be reconstructed to a precise line of sight and back to an area of space about a billion light-years away that contains only a small number of possible home galaxies," says Shannon. The cosmic web is very difficult to spot because most of the plasma and gas it contains is very faint. It is usually detected when large sections of it are lit up briefly, for example by a bright quasar or a FRB. This particular flash reached the Parkes radio telescope mid last year and is described in Science.
News Article | September 14, 2016
The research, made possible by cutting-edge AAO instrumentation, means that astronomers can now classify galaxies according to their physical properties rather than human interpretation of a galaxy's appearance. For the past 200 years, telescopes have been capable of observing galaxies beyond our own galaxy, the Milky Way. Only a few were visible to begin with but as telescopes became more powerful, more galaxies were discovered, making it crucial for astronomers to come up with a way to consistently group different types of galaxies together. In 1926, the famous American astronomer Edwin Hubble refined a system that classified galaxies into categories of spiral, elliptical, lenticular or irregular shape. This system, known as the Hubble sequence, is the most common way of classifying galaxies to this day. Despite its success, the criteria on which the Hubble scheme is based are subjective, and only indirectly related to the physical properties of galaxies. This has significantly hampered attempts to identify the evolutionary pathways followed by different types of galaxies as they slowly change over billions of years. Dr Luca Cortese, from The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), said the world's premier astronomical facilities are now producing surveys consisting of hundreds of thousands of galaxies rather than the hundreds that Hubble and his contemporaries were working with. "We really need a way to classify galaxies consistently using instruments that measure physical properties rather than a time consuming and subjective technique involving human interpretation," he said. In a study led by Dr Cortese, a team of astronomers has used a technique known as Integral Field Spectroscopy to quantify how gas and stars move within galaxies and reinterpret the Hubble sequence as a physically based two-dimensional classification system. "Thanks to the development of new technologies, we can map in great detail the distribution and velocity of different components of galaxies. Then, using this information we're able to determine the overall angular momentum of a galaxy, which is the key physical quantity affecting how the galaxy will evolve over billions of years. "Remarkably, the galaxy types described by the Hubble scheme appear to be determined by two primary properties of galaxies–mass and angular momentum. This provides us with a physical interpretation for the well known Hubble sequence whilst removing the subjectiveness and bias of a visual classification based on human perception rather than actual measurement." The new study involved 488 galaxies observed by the 3.9m Anglo Australian Telescope in New South Wales and an instrument attached to the telescope called the Sydney-AAO Multi-object Integral-field spectrograph or 'SAMI'. The SAMI project, led by the University of Sydney and the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), aims to create one of the first large-scale resolved survey of galaxies, measuring the velocity and distribution of gas and stars of different ages in thousands of systems. "Australia has a lot of expertise with this type of astronomy and is really at the forefront of what's being done," said Professor Warrick Couch, Director of the Australian Astronomical Observatory and CAASTRO Partner Investigator. "For the SAMI instrument we succeeded in putting 61 optical fibres within a distance that's less than half the width of a human hair. "That's no small feat, it's making this type of work possible and attracting interest from astronomers and observatories from around the world." Future upgrades of the instrument are planned that will allow astronomers to obtain even sharper maps of galaxies and further their understanding of the physical processes shaping the Hubble sequence. "As we get better at doing this and the instruments we're using are upgraded, we should be able to look for the physical triggers that cause one type of galaxy to evolve into another—that's really exciting stuff," Dr Cortese said. More information: The SAMI Galaxy Survey: the link between angular momentum and optical morphology. arxiv.org/abs/1608.00291
News Article | October 26, 2016
Published today in the Monthly Notices of the Royal Astronomical Society, the GaLactic and Extragalactic All-sky MWA, or 'GLEAM' survey, has produced a catalogue of 300,000 galaxies observed by the Murchison Widefield Array (MWA), a $50 million radio telescope located at a remote site north-east of Geraldton. Lead author Dr Natasha Hurley-Walker, from Curtin University and the International Centre for Radio Astronomy Research (ICRAR), said this is the first radio survey to image the sky in such amazing technicolour. "The human eye sees by comparing brightness in three different primary colours – red, green and blue," she said. "GLEAM does rather better than that, viewing the sky in each of 20 primary colours. That's much better than we humans can manage, and it even beats the very best in the animal kingdom, the mantis shrimp, which can see 12 different primary colours." GLEAM is a large-scale, high-resolution survey of the radio sky observed at frequencies from 70 to 230 MHz, observing radio waves that have been travelling through space—some for billions of years. "Our team are using this survey to find out what happens when clusters of galaxies collide," Dr Hurley-Walker said. "We're also able to see the remnants of explosions from the most ancient stars in our galaxy, and find the first and last gasps of supermassive black holes." MWA director Dr Randall Wayth said GLEAM is one of the biggest radio surveys of the sky ever assembled. "The area surveyed is enormous," he said. "Large sky surveys like this are extremely valuable to scientists and they're used across many areas of astrophysics, often in ways the original researchers could never have imagined." Completing the GLEAM survey with the Murchison Widefield Array is a big step on the path to SKA-low, the low frequency part of the international Square Kilometre Array radio telescope to be built in Australia in the coming years. "It's a significant achievement for the MWA telescope and the team of researchers that have worked on the GLEAM survey," Dr Wayth said. "The survey gives us a glimpse of the Universe that SKA-low will be probing once it's built. By mapping the sky in this way we can help fine-tune the design for the SKA and prepare for even deeper observations into the distant Universe." Explore further: Astronomers smash cosmic records to see hydrogen in distant galaxy More information: Original publication, 'GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue', published in the Monthly Notices of the Royal Astronomical Society onOctober 27th, 2016. Available from s3-ap-southeast-2.amazonaws.com/icrar.org/wp-content/uploads/2016/10/18223055/GLEAM-Paper_sml.pdf
News Article | October 27, 2016
A telescope located deep in the West Australian outback has shown what the Universe would look like if human eyes could see radio waves. Published today in the Monthly Notices of the Royal Astronomical Society, the GaLactic and Extragalactic All-sky MWA, or 'GLEAM' survey, has produced a catalogue of 300,000 galaxies observed by the Murchison Widefield Array (MWA), a $50 million radio telescope located at a remote site northeast of Geraldton. Lead author Dr Natasha Hurley-Walker, from Curtin University and the International Centre for Radio Astronomy Research (ICRAR), said this is the first radio survey to image the sky in such amazing technicolour. "The human eye sees by comparing brightness in three different primary colours - red, green and blue," Dr Hurley-Walker said. "GLEAM does rather better than that, viewing the sky in 20 primary colours. "That's much better than we humans can manage, and it even beats the very best in the animal kingdom, the mantis shrimp, which can see 12 different primary colours," she said. GLEAM is a large-scale, high-resolution survey of the radio sky observed at frequencies from 70 to 230 MHz, observing radio waves that have been travelling through space--some for billions of years. "Our team are using this survey to find out what happens when clusters of galaxies collide," Dr Hurley-Walker said. "We're also able to see the remnants of explosions from the most ancient stars in our galaxy, and find the first and last gasps of supermassive black holes." MWA Director Associate Professor Randall Wayth, from Curtin University and ICRAR, said GLEAM is one of the biggest radio surveys of the sky ever assembled. "The area surveyed is enormous," he said. "Large sky surveys like this are extremely valuable to scientists and they're used across many areas of astrophysics, often in ways the original researchers could never have imagined," Associate Professor Wayth said. Completing the GLEAM survey with the MWA is a big step on the path to SKA-low, the low frequency part of the international Square Kilometre Array (SKA) radio telescope to be built in Australia in the coming years. "It's a significant achievement for the MWA telescope and the team of researchers that have worked on the GLEAM survey," Associate Professor Wayth said. "The survey gives us a glimpse of the Universe that SKA-low will be probing once it's built. By mapping the sky in this way we can help fine-tune the design for the SKA and prepare for even deeper observations into the distant Universe." 'GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue', published in the Monthly Notices of the Royal Astronomical Society on October 27th, 2016. The Murchison Widefield Array (MWA) is a low frequency radio telescope located at the Murchison Radio-astronomy Observatory in Western Australia's Mid West. The MWA observes radio waves with frequencies between 70 and 320 MHz and was the first of the three Square Kilometre Array (SKA) precursors to be completed. A consortium of 13 partner institutions from four countries (Australia, USA, India and New Zealand) has financed the development, construction, commissioning and operations of the facility. Since commencing operations in mid 2013 the consortium has grown to include new partners from Canada and Japan. Key science for the MWA ranges from the search for redshifted HI signals from the Epoch of Reionisation to wide-field searches for transient and variable objects (including pulsars and Fast Radio Bursts), wide-field Galactic and extra-galactic surveys, and solar and heliospheric science. The Square Kilometre Array (SKA) project is an international effort to build the world's largest radio telescope, led by SKA Organisation based at the Jodrell Bank Observatory near Manchester, England. Co-located primarily in South Africa and Western Australia, the SKA will be a collection of hundreds of thousands of radio antennas with a combined collecting area equivalent to approximately one million square metres, or one square kilometre. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility. The International Centre for Radio Astronomy Research (ICRAR) is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia. High-resolution videos and imagery are available from http://www. (password = 'glimmer').
News Article | February 17, 2017
A minor planet in the Solar System will officially be known as Bernardbowen from today after Australian citizen science project theSkyNet won a competition to name the celestial body. The minor planet was named by the International Centre for Radio Astronomy Research (ICRAR) in honour of their founding chairman Dr Bernard Bowen. Bernardbowen sits in the asteroid belt between Mars and Jupiter and takes 3.26 Earth years to orbit the Sun. The minor planet was discovered on October 28, 1991, and until now has been known as (6196) 1991 UO4. Based at ICRAR, theSkyNet has been running since 2011 and sees citizen scientists donating their spare computing power to help Australian astronomers uncover the mysteries of the Universe. Its 50,000-odd volunteers entered an International Astronomical Union (IAU) contest to name planets beyond our Solar System. Project founders ICRAR also won the right to name a minor planet within our Solar System. Bernardbowen was one of 17 minor planets to be christened today. Other newly named minor planets include Kagura, after a traditional Shinto theatrical dance, and Mehdia, which is equivalent to the Arabic word for gift. Dr Bowen is renowned as one of the country's finest science administrators and has presided over scientific advances ranging from the oceans to the skies. He was instrumental in the establishment of ICRAR in 2009, and helped bring part of the Square Kilometre Array telescope to Western Australia. A full list of the citation of the minor planets can be found at the IAU Minor Planet Circular. http://bit. Bernardbowen on the Minor Planet Centre site, including an interactive showing its position in the Solar System. http://bit. Images of the orbit of minor planet Bernardbowenare available at http://www. A minor planet is an astronomical object in direct orbit around the Sun that is neither a planet nor exclusively classified as a comet. Minor planets can be dwarf planets, asteroids, trojans, centaurs, Kuiper belt objects, and other trans-Neptunian objects. The International Centre for Radio Astronomy Research (ICRAR) is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia. http://www. By connecting 100s and 1000s of computers together through the Internet, it's possible to simulate a single machine capable of doing some pretty amazing stuff. That's what theSkyNet is all about - using your spare computing power to process radio astronomy data. http://www. The IAU is the international astronomical organisation that brings together more than 10 000 professional astronomers from almost 100 countries. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. The IAU also serves as the internationally recognised authority for assigning designations to celestial bodies and the surface features on them. Founded in 1919, the IAU is the world's largest professional body for astronomers. http://www.
News Article | January 20, 2017
An astronomic phenomenon, called ram-pressure stripping, drives gas from galaxies and condemns them to premature death because of the deprivation of material needed for the process of star formation. The research investigating this occurrence was conducted by a global team of researchers. The study, published Jan. 16, in the journal Monthly Notices of the Royal Astronomical Society, was carried out at the International Centre for Radio Astronomy Research as an attempt to better understand this phenomenon and its consequences. The research analyzed 10,600 satellite galaxies and concluded that the gas is stripped away at a very fast pace all over the local universe. The gas is a vital element when it comes to star formation, without which these cannot be created. The universe, as we know it, is composed of matter, accounting for approximately 5 percent of the entire universe; dark matter, accounting for approximately 27 percent; and dark energy, accounting for the rest of 68 percent of our universe. Toby Brown, lead researcher and a PhD candidate at ICRAR, noted that galaxies are embedded in clouds of dark matter, carrying the name of dark matter halos. "During their lifetimes, galaxies can inhabit halos of different sizes, ranging from masses typical of our own Milky Way to halos thousands of times more massive. As galaxies fall through these larger halos, the superheated intergalactic plasma between them removes their gas in a fast-acting process called ram-pressure stripping," Brown noted. The process threatens the existing stars, as these cool off in the absence of gas, grow old, and die. The phenomenon also obstructs new stars from being formed. Prior to this research, it was known that the ram-pressure stripping phenomenon had an effect of galaxies in clusters. However, this new study shows that galaxies can be affected even on a significantly smaller level, when there is notably less dark matter around the galaxies. The vast majority of galaxies in our universe exist in groups, ranging between two to a hundred, which obstructs star formation on a large level, affecting all the galaxies that are part of the cluster. "Our results are then compared with state-of-the-art semi-analytic models and hydrodynamical simulations and discussed within this framework, showing that more work is needed if models are to reproduce the observations. We conclude that the observed decrease of gas content in the group and cluster environments cannot be reproduced by starvation of the gas supply alone and invoke fast acting processes such as ram-pressure stripping of cold gas to explain this," noted the research. However, while this situation raises concern among specialists, another recent study, published in October 2016, suggests that there actually are ten times more galaxies in the observable universe than previously thought. "The missing 90 percent of the universe's galaxies are too faint and too far away to be detected by the current crop of telescopes, including Hubble. To uncover them, astronomers will have to wait for much larger and more powerful future telescopes. The researchers arrived at their result by painstakingly converting Hubble deep-field images into 3-D pictures so they could make accurate measurements of the number of galaxies at different epochs in the universe's history," stated the paper's press release. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | October 21, 2016
A grand hydrogen map of the Milky Way has been prepared by scientists for the first time, revealing new information regarding the spaces between stars. The superior map HI4PI was compiled after taking vast data from two huge radio telescopes: the Max Planck radio telescope in Germany and CSIRO radio telescope in Australia. The HI4PI survey mapped neutral atomic hydrogen, considering its abundance in space and status as the main component of stars and galaxies. The meticulous study comes after millions of personal observations and data points that numbered more than 10 billion. Published in Astronomy & Astrophysics, the new mapping scores over a previous study, which was named the Leiden-Argentine-Bonn (LAB) survey in terms of sensitivity and angular resolution. Reflecting on the merits of the new map, University of Bonn astronomer Jürgen Kerp called it a big leap over the earlier study, which was hamstrung by the difficult sampling of the sky. According to him, in HI4PI data, pilot studies were showing a wealth of structures unseen before. In the new map, even tiny clouds are visible. That is important because they are vital as having been instrumental in hastening the formation of stars in the Milky Way. Thanks to more than a million individual observations, the new outcome is telling the tale with all fine details of the structures between stars, according to the German and Australian scientists. The data gathered by the big radio telescopes reflect the cumulative hydrogen content and explain the locations of so many dwarf galaxies. "We've been able to produce a whole-sky image that in many ways are greater than the sum of its parts," Lister Staveley-Smith of the International Center for Radio Astronomy Research (ICRAR) said. Star formation in the Milky Way for billions of years has been abetted by gas clouds. From the map, convincing answers on questions related to the Milky Way, and galaxies in the neighborhood, can be obtained. According to Staveley-Smith, mysteries such as the source of gas for the Milky Way for sustained star formation and the position of dwarf galaxies have been answered by the new study, and it certainly has more excitement in store. The project, which used 10 billion individual data points, revealed that the Milky Way as a galactic home contains 400 billion stars. The distance of the solar system from the Galactic Center is an average 27,000 light years. In short, the HI4PI map marks the great strides made in astronomy after the advent of new telescopes and use of latest scientific techniques. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | October 27, 2016
Maybe you’ve always wondered what the universe would look like if you could see radio waves ― or maybe not. Either way, you’ll be wowed by this extraordinary new view of the cosmos as seen by the Murchison Widefield Array (MWA) radio telescope in the Australian outback. Even astronomers are awed by the view, a product of the Galactic and Extragalactic All-Sky MWA (GLEAM) survey of 300,000 galaxies in frequencies from 70 to 230 megahertz. “The human eye sees by comparing brightness in three different primary colors ― red, green and blue,” Dr. Natasha Hurley-Walker, an early career research fellow at the International Centre for Radio Astronomy Research (ICRAR) in Bentley, Western Australia, and the lead author of a new paper describing the the survey, said in a press statement. “GLEAM does rather better than that, viewing the sky in 20 primary colors.” For an even more spectacular viewing experience, the “Gleamoscope” tool (below) lets you see the universe as it appears across the electromagnetic spectrum ― from radio waves and microwaves, to far-infrared and visible light, to X-rays and gamma rays. The tool is based on the Chromoscope, an interactive graphic produced at Cardiff University in Wales, the New York Times reported. Hurley-Walker and her collaborators are interested in more than just pretty pictures, as you might imagine. “Large sky surveys like this are extremely valuable to scientists and they’re used across many areas of astrophysics, often in ways the original researchers could never have imagined,” ICRAR astronomer Dr. Randall Wayth, a co-author of the paper, said in the statement. Dr. Jay Pasachoff, an astronomer at Williams College in Williamstown, Massachusetts, called the GLEAM survey “important research” in an email to The Huffington Post. He added, “It’s great that there are new radio telescopes ... that are mapping the radio waves that come from celestial objects at finer resolutions than we had before.” Yale astrophysicist Dr. Meg Urry gave a similar assessment of the GLEAM research. In an email to HuffPost, she called it “a gold mine for scientists interested in many different areas.” The GLEAM astronomers are using the survey to find out what happens when clusters of galaxies collide, Hurley-Walker said, adding that they’re also able to see remnants of explosions from the oldest stars and supermassive black holes’ “last gasp.” Of course, the real gasps will be the ones from the people who see the image.
News Article | March 15, 2016
Zadko Telescope Director Associate Professor David Coward, from UWA's School of Physics, said the collaboration follows the recent revelation that the skies are teeming with short-lived exotic phenomena, named the "Transient Universe". The new project, SUPERB (SUrvey for Pulsars and Extragalactic Radio Bursts) will try and understand the origin of mysterious radio flashes. "These transients – flashes of light and radio bursts – are believed to originate from colliding black-holes or the formation of neutron stars, but no one knows for sure," Associate Professor Coward said. "They are completely unpredictable so we don't know when the next flash will occur, and where in the sky it will happen. To really understand such a phenomenon requires combining the signals from optical and radio telescopes, something that hasn't been successful in the past. "Until now it has taken many hours to interrupt other observing programs and to point telescopes in the same direction as the radio burst – our new collaboration will change all of that." Associate Professor Coward said the Zadko Telescope had already slashed the world record for the fastest response to a Parkes discovery of a radio burst – a near zero time delay – which was achieved by 'shadowing' Parkes, the NSW-based telescope made famous by the 2001 film "The Dish". "The Parkes Radio Telescope is in constant communication with the Zadko Telescope through the internet to ensure they are both pointing at the same sky location, something that is only possible when it is done robotically, with no human involvement," he said. In December 2015 the Zadko Telescope was shadowing Parkes at the same time a radio burst occurred. "The team is still searching for such an optical signature in the data – if a coincident signal is found it could reveal the hidden source of the flashes," Associate Professor Coward said. The cutting-edge project is led by Associate Professor Coward in collaboration with Dr Richard Dodson from the International Centre for Radio Astronomy Research (ICRAR) and French PhD student Damien Turpin, from Toulouse University. Dr Dodson said UWA's ownership of the Zadko Telescope, WA's premier optical telescope, provided a research-class resource. "It has an exceptionally wide view of the sky, where almost all the observing time can be dedicated to in-house projects, a combination of factors which has allowed us to perform some very unique science.," he said. Explore further: 11 billion year-old blast from the past captured by UWA Zadko Telescope