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Astronomers have found a system of seven Earth-sized planets just 40 light-years away. Using ground and space telescopes, including ESO's Very Large Telescope, the planets were all detected as they passed in front of their parent star, the ultracool dwarf star known as TRAPPIST-1. According to the paper appearing today in the journal Nature, three of the planets lie in the habitable zone and could harbour oceans of water on their surfaces, increasing the possibility that the star system could play host to life. This system has both the largest number of Earth-sized planets yet found and the largest number of worlds that could support liquid water on their surfaces. Astronomers using the TRAPPIST-South telescope at ESO's La Silla Observatory, the Very Large Telescope at Paranal and the NASA Spitzer Space Telescope, as well as other telescopes around the world [1], have now confirmed the existence of at least seven small planets orbiting the cool red dwarf star TRAPPIST-1) [2]. All the planets, labeled TRAPPIST-1b, c, d, e, f, g and h in order of increasing distance from their parent star, have sizes similar to Earth [3]. Dips in the star's light output caused by each of the seven planets passing in front of it -- events known as transits -- allowed the astronomers to infer information about their sizes, compositions and orbits [4]. They found that at least the inner six planets are comparable in both size and temperature to the Earth. Lead author Michaël Gillon of the STAR Institute at the University of Liège in Belgium is delighted by the findings: "This is an amazing planetary system -- not only because we have found so many planets, but because they are all surprisingly similar in size to the Earth!" With just 8% the mass of the Sun, TRAPPIST-1 is very small in stellar terms -- only marginally bigger than the planet Jupiter -- and though nearby in the constellation Aquarius (The Water Carrier), it appears very dim. Astronomers expected that such dwarf stars might host many Earth-sized planets in tight orbits, making them promising targets in the hunt for extraterrestrial life, but TRAPPIST-1 is the first such system to be found. Co-author Amaury Triaud expands: "The energy output from dwarf stars like TRAPPIST-1 is much weaker than that of our Sun. Planets would need to be in far closer orbits than we see in the solar system if there is to be surface water. Fortunately, it seems that this kind of compact configuration is just what we see around TRAPPIST-1!" The team determined that all the planets in the system are similar in size to Earth and Venus in the solar system, or slightly smaller. The density measurements suggest that at least the innermost six are probably rocky in composition. The planetary orbits are not much larger than that of Jupiter's Galilean moon system , and much smaller than the orbit of Mercury in the solar system. However, TRAPPIST-1's small size and low temperature mean that the energy input to its planets is similar to that received by the inner planets in our solar system; TRAPPIST-1c, d and f receive similar amounts of energy to Venus, Earth and Mars, respectively. All seven planets discovered in the system could potentially have liquid water on their surfaces, though their orbital distances make some of them more likely candidates than others. Climate models suggest the innermost planets, TRAPPIST-1b, c and d, are probably too hot to support liquid water, except maybe on a small fraction of their surfaces. The orbital distance of the system's outermost planet, TRAPPIST-1h, is unconfirmed, though it is likely to be too distant and cold to harbour liquid water -- assuming no alternative heating processes are occurring [5]. TRAPPIST-1e, f, and g, however, represent the holy grail for planet-hunting astronomers, as they orbit in the star's habitable zone and could host oceans of surface water [6]. These new discoveries make the TRAPPIST-1 system a very important target for future study. The NASA/ESA Hubble Space Telescope is already being used to search for atmospheres around the planets and team member Emmanuël Jehin is excited about the future possibilities: "With the upcoming generation of telescopes, such as ESO's European Extremely Large Telescope and the NASA/ESA/CSA James Webb Space Telescope , we will soon be able to search for water and perhaps even evidence of life on these worlds." [1] As well as the NASA Spitzer Space Telescope , the team used many ground-based facilities: TRAPPIST-South at ESO's La Silla Observatory in Chile, HAWK-I on ESO's Very Large Telescope in Chile, TRAPPIST-North in Morocco, the 3.8-metre UKIRT in Hawaii, the 2-metre Liverpool and 4-metre William Herschel telescopes at La Palma in the Canary Islands, and the 1-metre SAAO telescope in South Africa. [2] TRAPPIST-South (the TRAnsiting Planets and PlanetesImals Small Telescope-South) is a Belgian 0.6-metre robotic telescope operated from the University of Liège and based at ESO's La Silla Observatory in Chile. It spends much of its time monitoring the light from around 60 of the nearest ultracool dwarf stars and brown dwarfs ("stars" which are not quite massive enough to initiate sustained nuclear fusion in their cores), looking for evidence of planetary transits. TRAPPIST-South, along with its twin TRAPPIST-North, are the forerunners to the SPECULOOS system, which is currently being installed at ESO's Paranal Observatory. [3] In early 2016, a team of astronomers, also led by Michaël Gillon announced the discovery of three planets orbiting TRAPPIST-1. They intensified their follow-up observations of the system mainly because of a remarkable triple transit that they observed with the HAWK-I instrument on the VLT. This transit showed clearly that at least one other unknown planet was orbiting the star. And that historic light curve shows for the first time three temperate Earth-sized planets, two of them in the habitable zone, passing in front of their star at the same time! [4] This is one of the main methods that astronomers use to identify the presence of a planet around a star. They look at the light coming from the star to see if some of the light is blocked as the planet passes in front of its host star on the line of sight to Earth -- it transits the star, as astronomers say. As the planet orbits around its star, we expect to see regular small dips in the light coming from the star as the planet moves in front of it. [5] Such processes could include tidal heating , whereby the gravitational pull of TRAPPIST-1 causes the planet to repeatedly deform, leading to inner frictional forces and the generation of heat. This process drives the active volcanism on Jupiter's moon Io. If TRAPPIST-1h has also retained a primordial hydrogen-rich atmosphere, the rate of heat loss could be very low. [6] This discovery also represents the largest known chain of exoplanets orbiting in near-resonance with each other. The astronomers carefully measured how long it takes for each planet in the system to complete one orbit around TRAPPIST-1 -- known as the revolution period -- and then calculated the ratio of each planet's period and that of its next more distant neighbour. The innermost six TRAPPIST-1 planets have period ratios with their neighbours that are very close to simple ratios, such as 5:3 or 3:2. This means that the planets most likely formed together further from their star, and have since moved inwards into their current configuration. If so, they could be low-density and volatile-rich worlds, suggesting an icy surface and/or an atmosphere. "Seven Temperate Terrestrial Planets Around the Nearby Ultracool Dwarf Star TRAPPIST-1," M. Gillon et al., 2017 Feb. 23, Nature [http://www.nature.com, preprint (PDF): http://www.eso.org/public/archives/releases/sciencepapers/eso1706/eso1706a.pdf]. The team is composed of M. Gillon (Université de Liège, Liège, Belgium), A. H. M. J. Triaud (Institute of Astronomy, Cambridge, UK), B.-O. Demory (University of Bern, Bern, Switzerland; Cavendish Laboratory, Cambridge, UK), E. Jehin (Université de Liège, Liège, Belgium), E. Agol (University of Washington, Seattle, USA; NASA Astrobiology Institute's Virtual Planetary Laboratory, Seattle, USA), K. M. Deck (California Institute of Technology, Pasadena, CA, USA), S. M. Lederer (NASA Johnson Space Center, Houston, USA), J. de Wit (Massachusetts Institute of Technology, Cambridge, MA, USA), A. Burdanov (Université de Liège, Liège, Belgium), J. G. Ingalls (California Institute of Technology, Pasadena, California, USA), E. Bolmont (University of Namur, Namur, Belgium; Laboratoire AIM Paris-Saclay, CEA/DRF -- CNRS -- Univ. Paris Diderot -- IRFU/SAp, Centre de Saclay, France), J. Leconte (Univ. Bordeaux, Pessac, France), S. N. Raymond (Univ. Bordeaux, Pessac, France), F. Selsis (Univ. Bordeaux, Pessac, France), M. Turbet (Sorbonne Universités, Paris, France), K. Barkaoui (Oukaimeden Observatory, Marrakesh, Morocco), A. Burgasser (University of California, San Diego, California, USA), M. R. Burleigh (University of Leicester, Leicester, UK), S. J. Carey (California Institute of Technology, Pasadena, CA, USA), A. Chaushev (University of Leicester, UK), C. M. Copperwheat (Liverpool John Moores University, Liverpool, UK), L. Delrez (Université de Liège, Liège, Belgium; Cavendish Laboratory, Cambridge, UK), C. S. Fernandes (Université de Liège, Liège, Belgium), D. L. Holdsworth (University of Central Lancashire, Preston, UK), E. J. Kotze (South African Astronomical Observatory, Cape Town, South Africa), V. Van Grootel (Université de Liège, Liège, Belgium), Y. Almleaky (King Abdulaziz University, Jeddah, Saudi Arabia; King Abdullah Centre for Crescent Observations and Astronomy, Makkah Clock, Saudi Arabia), Z. Benkhaldoun (Oukaimeden Observatory, Marrakesh, Morocco), P. Magain (Université de Liège, Liège, Belgium), and D. Queloz (Cavendish Laboratory, Cambridge, UK; Astronomy Department, Geneva University, Switzerland). 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." Please follow SpaceRef on Twitter and Like us on Facebook.


News Article | February 24, 2017
Site: phys.org

Since that first sighting, SN 1987A has continued to fascinate astronomers with its spectacular light show. Located in the nearby Large Magellanic Cloud, it is the nearest supernova explosion observed in hundreds of years and the best opportunity yet for astronomers to study the phases before, during, and after the death of a star. To commemorate the 30th anniversary of SN 1987A, new images, time-lapse movies, a data-based animation based on work led by Salvatore Orlando at INAF-Osservatorio Astronomico di Palermo, Italy, and a three-dimensional model are being released. By combining data from NASA's Hubble Space Telescope and Chandra X-ray Observatory, as well as the international Atacama Large Millimeter/submillimeter Array (ALMA), astronomers—and the public—can explore SN 1987A like never before. Hubble has repeatedly observed SN 1987A since 1990, accumulating hundreds of images, and Chandra began observing SN 1987A shortly after its deployment in 1999. ALMA, a powerful array of 66 antennas, has been gathering high-resolution millimeter and submillimeter data on SN 1987A since its inception. "The 30 years' worth of observations of SN 1987A are important because they provide insight into the last stages of stellar evolution," said Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and the Gordon and Betty Moore Foundation in Palo Alto, California. The latest data from these powerful telescopes indicate that SN 1987A has passed an important threshold. The supernova shock wave is moving beyond the dense ring of gas produced late in the life of the pre-supernova star when a fast outflow or wind from the star collided with a slower wind generated in an earlier red giant phase of the star's evolution. What lies beyond the ring is poorly known at present, and depends on the details of the evolution of the star when it was a red giant. "The details of this transition will give astronomers a better understanding of the life of the doomed star, and how it ended," said Kari Frank of Penn State University who led the latest Chandra study of SN 1987A. Supernovas such as SN 1987A can stir up the surrounding gas and trigger the formation of new stars and planets. The gas from which these stars and planets form will be enriched with elements such as carbon, nitrogen, oxygen and iron, which are the basic components of all known life. These elements are forged inside the pre-supernova star and during the supernova explosion itself, and then dispersed into their host galaxy by expanding supernova remnants. Continued studies of SN 1987A should give unique insight into the early stages of this dispersal. Some highlights from studies involving these telescopes include: Hubble studies have revealed that the dense ring of gas around the supernova is glowing in optical light, and has a diameter of about a light-year. The ring was there at least 20,000 years before the star exploded. A flash of ultraviolet light from the explosion energized the gas in the ring, making it glow for decades. The central structure visible inside the ring in the Hubble image has now grown to roughly half a light-year across. Most noticeable are two blobs of debris in the center of the supernova remnant racing away from each other at roughly 20 million miles an hour. From 1999 until 2013, Chandra data showed an expanding ring of X-ray emission that had been steadily getting brighter. The blast wave from the original explosion has been bursting through and heating the ring of gas surrounding the supernova, producing X-ray emission. In the past few years, the ring has stopped getting brighter in X-rays. From about February 2013 until the last Chandra observation analyzed in September 2015 the total amount of low-energy X-rays has remained constant. Also, the bottom left part of the ring has started to fade. These changes provide evidence that the explosion's blast wave has moved beyond the ring into a region with less dense gas. This represents the end of an era for SN 1987A. Beginning in 2012, astronomers used ALMA to observe the glowing remains of the supernova, studying how the remnant is actually forging vast amounts of new dust from the new elements created in the progenitor star. A portion of this dust will make its way into interstellar space and may become the building blocks of future stars and planets in another system. These observations also suggest that dust in the early universe likely formed from similar supernova explosions. Astronomers also are still looking for evidence of a black hole or a neutron star left behind by the blast. They observed a flash of neutrinos from the star just as it erupted. This detection makes astronomers quite certain a compact object formed as the center of the star collapsed—either a neutron star or a black hole—but no telescope has uncovered any evidence for one yet. Astronomers combined observations from three different observatories to produce this colorful, multiwavelength image of the intricate remains of Supernova 1987A. Credit: NASA, ESA, and A. Angelich (NRAO/AUI/NSF); Hubble credit: NASA, ESA, and R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation) Chandra credit: NASA/CXC/Penn State/K. Frank et al.; ALMA credit: ALMA (ESO/NAOJ/NRAO) and R. Indebetouw (NRAO/AUI/NSF) Explore further: Space image: New supernova remnant lights up


News Article | February 22, 2017
Site: www.eurekalert.org

Astronomers using the TRAPPIST-South telescope at ESO's La Silla Observatory, the Very Large Telescope (VLT) at Paranal and the NASA Spitzer Space Telescope, as well as other telescopes around the world [1], have now confirmed the existence of at least seven small planets orbiting the cool red dwarf star TRAPPIST-1 [2]. All the planets, labelled TRAPPIST-1b, c, d, e, f, g and h in order of increasing distance from their parent star, have sizes similar to Earth [3]. Dips in the star's light output caused by each of the seven planets passing in front of it (astronomy) -- events known as transits -- allowed the astronomers to infer information about their sizes, compositions and orbits [4]. They found that at least the inner six planets are comparable in both size and temperature to the Earth. Lead author Michaël Gillon of the STAR Institute at the University of Liège in Belgium is delighted by the findings: "This is an amazing planetary system -- not only because we have found so many planets, but because they are all surprisingly similar in size to the Earth!" With just 8% the mass of the Sun, TRAPPIST-1 is very small in stellar terms -- only marginally bigger than the planet Jupiter -- and though nearby in the constellation Aquarius (constellation) ) (The Water Carrier), it appears very dim. Astronomers expected that such dwarf stars might host many Earth-sized planets in tight orbits, making them promising targets in the hunt for extraterrestrial life, but TRAPPIST-1 is the first such system to be found. Co-author Amaury Triaud expands: "The energy output from dwarf stars like TRAPPIST-1 is much weaker than that of our Sun. Planets would need to be in far closer orbits than we see in the Solar System if there is to be surface water. Fortunately, it seems that this kind of compact configuration is just what we see around TRAPPIST-1!" The team determined that all the planets in the system are similar in size to Earth and Venus in the Solar System, or slightly smaller. The density measurements suggest that at least the innermost six are probably rocky in composition. The planetary orbits are not much larger than that of Jupiter's Galilean moon system, and much smaller than the orbit of Mercury in the Solar System. However, TRAPPIST-1's small size and low temperature mean that the energy input to its planets is similar to that received by the inner planets in our Solar System; TRAPPIST-1c, d and f receive similar amounts of energy to Venus, Earth and Mars, respectively. All seven planets discovered in the system could potentially have liquid water on their surfaces, though their orbital distances make some of them more likely candidates than others. Climate models suggest the innermost planets, TRAPPIST-1b, c and d, are probably too hot to support liquid water, except maybe on a small fraction of their surfaces. The orbital distance of the system's outermost planet, TRAPPIST-1h, is unconfirmed, though it is likely to be too distant and cold to harbour liquid water -- assuming no alternative heating processes are occurring [5]. TRAPPIST-1e, f, and g, however, represent the holy grail for planet-hunting astronomers, as they orbit in the star's habitable zone[6]. These new discoveries make the TRAPPIST-1 system a very important target for future study. The NASA/ESA Hubble Space Telescope is already being used to search for atmospheres around the planets and team member Emmanuël Jehin is excited about the future possibilities: "With the upcoming generation of telescopes, such as ESO's European Extremely Large Telescope and the NASA/ESA/CSA James Webb Space Telescope , we will soon be able to search for water and perhaps even evidence of life on these worlds." [1] As well as the NASA Spitzer Space Telescope , the team used many ground-based facilities: TRAPPIST-South at ESO's La Silla Observatory in Chile, HAWK-I on ESO's Very Large Telescope in Chile, TRAPPIST-North in Morocco, the 3.8-metre UKIRT in Hawaii, the 2-metre Liverpool and 4-metre William Herschel telescopes at La Palma in the Canary Islands, and the 1-metre SAAO telescope in South Africa. [2] TRAPPIST-South (the TRAnsiting Planets and PlanetesImals Small Telescope-South) is a Belgian 0.6-metre robotic telescope operated from the University of Liège and based at ESO's La Silla Observatory in Chile. It spends much of its time monitoring the light from around 60 of the nearest ultracool dwarf stars and brown dwarfs ("stars" which are not quite massive enough to initiate sustained nuclear fusion in their cores), looking for evidence of planetary transits. TRAPPIST-South, along with its twin TRAPPIST-North, are the forerunners to the SPECULOOS system, which is currently being installed at ESO's Paranal Observatory. [3] In early 2016, a team of astronomers, also led by Michaël Gillon announced the discovery of three planets orbiting TRAPPIST-1. They intensified their follow-up observations of the system mainly because of a remarkable triple transit that they observed with the HAWK-I instrument on the VLT. This transit showed clearly that at least one other unknown planet was orbiting the star. And that historic light curve shows for the first time three temperate Earth-sized planets, two of them in the habitable zone, passing in front of their star at the same time! [4] This is one of the main methods that astronomers use to identify the presence of a planet around a star. They look at the light coming from the star to see if some of the light is blocked as the planet passes in front of its host star on the line of sight to Earth -- it transits (astronomy) the star, as astronomers say. As the planet orbits around its star, we expect to see regular small dips in the light coming from the star as the planet moves in front of it. [5] Such processes could include tidal heating, whereby the gravitational pull of TRAPPIST-1 causes the planet to repeatedly deform, leading to inner frictional forces and the generation of heat. This process drives the active volcanism on Jupiter's moon Io. If TRAPPIST-1h has also retained a primordial hydrogen-rich atmosphere, the rate of heat loss could be very low. [6] This discovery also represents the largest known chain of exoplanets orbiting in near-resonance with each other. The astronomers carefully measured how long it takes for each planet in the system to complete one orbit around TRAPPIST-1 -- known as the revolution period -- and then calculated the ratio of each planet's period and that of its next more distant neighbour. The innermost six TRAPPIST-1 planets have period ratios with their neighbours that are very close to simple ratios, such as 5:3 or 3:2. This means that the planets most likely formed together further from their star, and have since moved inwards into their current configuration. If so, they could be low-density and volatile-rich worlds, suggesting an icy surface and/or an atmosphere. This research was presented in a paper entitled "Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1", by M. Gillon et al., to appear in the journal Nature. The team is composed of M. Gillon (Université de Liège, Liège, Belgium), A. H. M. J. Triaud (Institute of Astronomy, Cambridge, UK), B.-O. Demory (University of Bern, Bern, Switzerland; Cavendish Laboratory, Cambridge, UK), E. Jehin (Université de Liège, Liège, Belgium), E. Agol (University of Washington, Seattle, USA; NASA Astrobiology Institute's Virtual Planetary Laboratory, Seattle, USA), K. M. Deck (California Institute of Technology, Pasadena, CA, USA), S. M. Lederer (NASA Johnson Space Center, Houston, USA), J. de Wit (Massachusetts Institute of Technology, Cambridge, MA, USA), A. Burdanov (Université de Liège, Liège, Belgium), J. G. Ingalls (California Institute of Technology, Pasadena, California, USA), E. Bolmont (University of Namur, Namur, Belgium; Laboratoire AIM Paris-Saclay, CEA/DRF - CNRS - Univ. Paris Diderot - IRFU/SAp, Centre de Saclay, France), J. Leconte (Univ. Bordeaux, Pessac, France), S. N. Raymond (Univ. Bordeaux, Pessac, France), F. Selsis (Univ. Bordeaux, Pessac, France), M. Turbet (Sorbonne Universités, Paris, France), K. Barkaoui (Oukaimeden Observatory, Marrakesh, Morocco), A. Burgasser (University of California, San Diego, California, USA), M. R. Burleigh (University of Leicester, Leicester, UK), S. J. Carey (California Institute of Technology, Pasadena, CA, USA), A. Chaushev (University of Leicester, UK), C. M. Copperwheat (Liverpool John Moores University, Liverpool, UK), L. Delrez (Université de Liège, Liège, Belgium; Cavendish Laboratory, Cambridge, UK), C. S. Fernandes (Université de Liège, Liège, Belgium), D. L. Holdsworth (University of Central Lancashire, Preston, UK), E. J. Kotze (South African Astronomical Observatory, Cape Town, South Africa), V. Van Grootel (Université de Liège, Liège, Belgium), Y. Almleaky (King Abdulaziz University, Jeddah, Saudi Arabia; King Abdullah Centre for Crescent Observations and Astronomy, Makkah Clock, Saudi Arabia), Z. Benkhaldoun (Oukaimeden Observatory, Marrakesh, Morocco), P. Magain (Université de Liège, Liège, Belgium), and D. Queloz (Cavendish Laboratory, Cambridge, UK; Astronomy Department, Geneva University, Switzerland). 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 | March 1, 2017
Site: www.eurekalert.org

The events surrounding the Big Bang were so cataclysmic that they left an indelible imprint on the fabric of the cosmos. We can detect these scars today by observing the oldest light in the universe. As it was created nearly 14 billion years ago, this light -- which exists now as weak microwave radiation and is thus named the cosmic microwave background (CMB) -- permeates the entire cosmos, filling it with detectable photons. The CMB can be used to probe the cosmos via something known as the Sunyaev-Zel'dovich (SZ) effect, which was first observed over 30 years ago. We detect the CMB here on Earth when its constituent microwave photons travel to us through space. On their journey to us, they can pass through galaxy clusters that contain high-energy electrons. These electrons give the photons a tiny boost of energy. Detecting these boosted photons through our telescopes is challenging but important -- they can help astronomers to understand some of the fundamental properties of the universe, such as the location and distribution of dense galaxy clusters. The NASA/ESA (European Space Agency) Hubble Space Telescope observed one of most massive known galaxy clusters, RX J1347.5-1145, seen in this Picture of the Week, as part of the Cluster Lensing And Supernova survey with Hubble (CLASH). This observation of the cluster, 5 billion light-years from Earth, helped the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to study the cosmic microwave background using the thermal Sunyaev-Zel'dovich effect. The observations made with ALMA are visible as the blue-purple hues.


News Article | February 27, 2017
Site: news.yahoo.com

Discovered 30 years ago, Supernova 1987A is one of the brightest exploding stars of the last four centuries. To commemorate its anniversary, NASA has now released a tranche of new data about the spectacular star, including striking imagery and time-lapse video. The supernova is the closest star explosion seen in centuries, presenting an unique opportunity for astronomers to study the progress of the star’s death. The images, animations and time-lapse video have been created from data from NASA’s Hubble Space Telescope, Chandra X-ray Observatory and ALMA. All three instruments have been collecting data about the star’s explosion since it was first discovered in 1987. “The 30 years’ worth of observations of SN 1987A are important because they provide insight into the last stages of stellar evolution,” said Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and the Gordon and Betty Moore Foundation in Palo Alto, California. NASA ESA R Kirshner Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation and M Mutchler and R Avila STScI SN 1987A can be seen at the centre of this image, resembling a white eye with a bright white pupil. The image can be viewed in full here. The data suggests the supernova has passed a critical threshold: the shockwave is now beyond the ring of gas produced late in the life of the pre-supernova. It’s knot known what lies beyond the ring. “The details of this transition will give astronomers a better understanding of the life of the doomed star, and how it ended,” said Kari Frank of Penn State University who led the latest Chandra study of SN 1987A. Supernovas occur when a change in a star’s core causes it to explode. They are the brightest explosions in space. Edward H. White II, pilot of the Gemini 4 spacecraft, floats in the zero gravity of space with an earth limb backdrop circa November 1965. Kinescope images of astronaut Commander Neil Armstrong in the Apollo 11 space shuttle during the space mission to land on the moon for the first time in history on July 20, 1969 The ascent stage of Orion, the Apollo 16 Lunar Module, lifts of from its descent stage to rendezvous with the Apollo 16 Command and Service Module, Casper, with astronaut Thomas Mattingly aboard in lunar orbit on 23rd April 1972. Five NASA astronauts aboard the Space Shuttle Atlantis look out overhead windows on the aft flight deck toward their counterparts aboard the Mir Space Station in March of 1996. Photograph of the Milky Way Galaxy captured by NASA's Spitzer Space Telescope. Dated 2007. The exhaust plume from space shuttle Atlantis is seen through the window of a Shuttle Training Aircraft (STA) as it launches from launch pad 39A at the Kennedy Space Center July 8, 2011 in Cape Canaveral, Florida. A United Launch Alliance Delta 4 rocket carrying NASA's first Orion deep space exploration craft sits on its launch pad as it is prepared for a 7:05 AM launch on December 4, 2014 in Cape Canaveral, Florida. A military pilot sits in the cockpit of an X-15 experimental rocket aircraft, wearing an astronaut's spacesuit circa 1959. Echo 1, a spherical balloon with a metalized skin, was launched by NASA on 12th August 1960. Once in orbit the balloon was inflated until it reached its intended diameter of 30 metres and it was then used as a reflector to bounce radio signals across the oceans. Four views of Earth rising above the lunar horizon, photographed by the crew of the Apollo 10 Lunar Module, while in lunar orbit, May 1969. American geologist and Apollo 17 astronaut Harrison Hagan Schmitt stands next to the US flag on the surface of the moon, during a period of EVA (Extra-Vehicular Activity) at the Taurus-Littrow landing site, December 1972. The space shuttle 'Enterprise' (NASA Orbiter Vehicle 101) makes its way along Rideout Road (Alabama State Route 255) to the Marshall Space Flight Center near Huntsville, Alabama, 15th March 1978. A crowd of people, viewed from behind, watch the launch of the first NASA Space Shuttle mission (STS-1), with Columbia (OV-102) soaring up into the sky, leaving a trail of exhaust smoke, in the distance from the launchpad at the Kennedy Space Center, Florida, USA, 12 April 1981. Astronaut Bruce McCandless II photographed at his maximum distance (320 ft) from the Space Shuttle Challenger during the first untethered EVA, made possible by his nitrogen jet propelled backpack (Manned Manuevering Unit or MMU) in 1984. Aerial shot of the launch of Space Shuttle Discovery (STS-41-D) as it takes off, leaving a trail of exhaust smoke, from Kennedy Space Center, Florida, USA, 30 August 1984. An astronaut's bootprint leaves a mark on the lunar surface July 20, 1969 on the moon. The 30th anniversary of the Apollo 11 Moon mission is celebrated July 20, 1999. Astronaut Charles Moss Duke, Jr. leaves a photograph of his family on the surface of the moon during the Apollo 16 lunar landing mission, 23rd April 1972.


Now scientists from MIT, the University of Cambridge, and elsewhere may have an answer. In a paper published today in the Astrophysical Journal, the team reports observing jets of hot, 10-million-degree gas blasting out from the central galaxy's black hole and blowing large bubbles out into the surrounding plasma. These jets normally act to quench star formation by blowing away cold gas—the main fuel that a galaxy consumes to generate stars. However, the researchers found that the hot jets and bubbles emanating from the center of the Phoenix cluster may also have the opposite effect of producing cold gas, that in turn rains back onto the galaxy, fueling further starbursts. This suggests that the black hole has found a way to recycle some of its hot gas as cold, star-making fuel. "We have thought the role of black hole jets and bubbles was to regulate star formation and to keep cooling from happening," says Michael McDonald, assistant professor of physics in MIT's Kavli Institute for Astrophysics and Space Research. "We kind of thought they were one-trick ponies, but now we see they can actually help cooling, and it's not such a cut-and-dried picture." The new findings help to explain the Phoenix cluster's exceptional star-producing power. They may also provide new insight into how supermassive black holes and their host galaxies mutually grow and evolve. McDonald's co-authors include lead author Helen Russell, an astronomer at Cambridge University; and others from the University of Waterloo, the Harvard-Smithsonian Center for Astrophysics, the University of Illinois, and elsewhere. The team analyzed observations of the Phoenix cluster gathered by the Atacama Large Millimeter Array (ALMA), a collection of 66 large radio telescopes spread over the desert of northern Chile. In 2015, the group obtained permission to direct the telescopes at the Phoenix cluster to measure its radio emissions and to detect and map signs of cold gas. The researchers looked through the data for signals of carbon monoxide, a gas that is present wherever there is cold hydrogen gas. They then converted the carbon monoxide emissions to hydrogen gas, to generate a map of cold gas near the center of the Phoenix cluster. The resulting picture was a puzzling surprise. "You would expect to see a knot of cold gas at the center, where star formation happens," McDonald says. "But we saw these giant filaments of cold gas that extend 20,000 light years from the central black hole, beyond the central galaxy itself. It's kind of beautiful to see." The team had previously used NASA's Chandra X-Ray Observatory to map the cluster's hot gas. These observations produced a picture in which powerful jets flew out from the black hole at close to the speed of light. Further out, the researchers saw that the jets inflated giant bubbles in the hot gas. When the team superimposed its picture of the Phoenix cluster's cold gas onto the map of hot gas, they found a "perfect spatial correspondence": The long filaments of frigid, 10-kelvins gas appeared to be draped over the bubbles of hot gas. "This may be the best picture we have of black holes influencing the cold gas," McDonald says. What the researchers believe to be happening is that, as jet inflate bubbles of hot, 10-million-degree gas near the black hole, they drag behind them a wake of slightly cooler, 1-million-degree gas. The bubbles eventually detach from the jets and float further out into the galaxy cluster, where each bubble's trail of gas cools, forming long filaments of extremely cold gas that condense and rain back onto the black hole as fuel for star formation. "It's a very new idea that the bubbles and jets can actually influence the distribution of cold gas in any way," McDonald says. Scientists have estimated that there is enough cold gas near the center of the Phoenix cluster to keep producing stars at a high rate for another 30 to 40 million years. Now that the researchers have identified a new feedback mechanism that may supply the black hole with even more cold gas, the cluster's stellar output may continue for much longer. "As long as there's cold gas feeding it, the black hole will keep burping out these jets," McDonald says. "But now we've found that these jets are making more food, or cold gas. So you're in this cycle that, in theory, could go on for a very long time." He suspects the reason the black hole is able to generate fuel for itself might have something to do with its size. If the black hole is relatively small, it may produce jets that are too weak to completely blast cold gas away from the cluster. "Right now [the black hole] may be pretty small, and it'd be like putting a civilian in the ring with Mike Tyson," McDonald says. "It's just not up to the task of blowing this cold gas far enough away that it would never come back." The team is hoping to determine the mass of the black hole, as well as identify other, similarly extreme starmakers in the universe.


Last year researchers "heard" black holes for the first time, when they detected the gravitational waves unleashed as two of them crashed together and merged. Now, they want to see a black hole, or at least its silhouette. Next month, astronomers will harness radio telescopes across the globe to create the equivalent of a single Earth-spanning dish—an instrument powerful enough, they hope, to image black holes backlit by the incandescent gas swirling around them. Their targets are the supermassive black hole at the heart of our Milky Way galaxy, known as Sagittarius A* (Sgr A*), and an even bigger one in the neighboring galaxy M87. Earlier observations using this Event Horizon Telescope (EHT) without its full roster of dishes yielded tantalizing results, but in images the two black holes remained featureless blobs. This year, for the first time, the EHT will add dishes in Chile and Antarctica, sharpening its resolution and raising expectations. Astronomers now hope to see how the black holes whip the hot gas around them into accretion disks and spawn matter-spewing jets. They also hope to chart the size and shape of the event horizon—the boundary of the black hole—to test whether Albert Einstein's theory of gravity, general relativity, still works under such extreme conditions. "It's a very bold and gutsy experiment," says theoretical astrophysicist Roger Blandford of Stanford University in Palo Alto, California, who is not involved in the project. Blandford believes the EHT may not only show how black holes work, but also deliver a more fundamental message. "It will validate this remarkable proposition: that black holes are common in the universe. Seeing is believing." The EHT takes aim just once a year, when good weather is likely, when both black holes are visible in the sky, and when it's possible to get time at all the observatories around the globe. This year, the team will observe for 5 nights during a 10-night window from 5 to 14 April. Then, an intensive data processing effort begins, and it may be a year before they know whether they've succeeded. "It's an exercise in delayed gratification. Delayed gratification squared," says EHT director Shep Doeleman at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. Imaging black holes is a formidable challenge, and not just because their intense gravity prevents even light from escaping. They are also surprisingly small. Sgr A* is calculated to contain the mass of 4 million suns, based on the nervy, high-speed orbits of stars in its gravitational grip. But its event horizon, the point of no return for anything approaching a black hole, is 24 million kilometers across, just 17 times wider than the sun. To see something so small from 26,000 light-years away requires a telescope dish of global dimensions. At optical wavelengths, Sgr A* is hidden by the shroud of dust and gas obscuring the galaxy's heart. Radio waves can pass through more easily, but ordinary radio dishes are still hampered by ionized gas clouds and low resolution. Best are telescopes sensitive to the shortest radio waves—millimeter waves—but the dishes, detectors, and data processing technology for this part of the spectrum were developed only in the past few decades. "There is only a tiny window where we can see the event horizon," says Heino Falcke, an astrophysicist at Radboud University in Nijmegen, the Netherlands, and chair of the EHT science council. "The Milky Way is like a milky glass." Early this decade, Doeleman and other EHT researchers began testing the idea with millimeter-sensitive dishes in Hawaii, California, and Arizona. Later, they extended the array to include the Large Millimeter Telescope in Mexico. Along the way, they got a good enough image of the black hole in M87 to see the base of its matter-spewing jets—data that are helping them understand how the jets are created. In 2015, they glimpsed the magnetic field around Sgr A*, which may help explain how black holes heat up the material around them. But to see the event horizon itself, the EHT had to grow even larger. Over the years, it has evolved from a loose, poorly funded group to a worldwide collaboration involving 30 institutions in 12 countries. Next month it will include farflung additions, including the IRAM dish in Spain, the South Pole Telescope, and the Atacama Large Millimeter/submillimeter Array (ALMA), a large international observatory comprising 66 dishes in northern Chile. With its huge dish area, ALMA is the big catch because it will boost the EHT's sensitivity by an order of magnitude. "That's the key for us," Doeleman says. Adding new instruments isn't simple. The technique for combining signals from distant dishes is known as very long baseline interferometry, and most millimeter-wave telescopes are not equipped to take part. EHT researchers had to visit each facility to tinker with its hardware and install new digital signal processors and data recorders. In the case of ALMA, that took some persuading. "We had to go into the bowels of ALMA and rewire it," Doeleman says. "It required political buy-in at all levels." The campaign next month will be a nervous time for the EHT team. All eight observatories need clear skies and no technical glitches to get the best possible observations. "The first time, things can go wrong," Falcke says. Data volumes will be so large that they have to be recorded on hard drives and shipped back to the Haystack Observatory in Westford, Massachusetts, and the Max Planck Institute for Radio Astronomy in Bonn, Germany, for processing. There, devices known as correlators, made from clusters of PCs but with the power of supercomputers, will spend months crunching through the data, combining the signals from separate dishes as if they came from a single dish as wide as Earth. Adding further delay, data from the South Pole Telescope won't arrive until September or October, when planes can retrieve the hard drives after the Antarctic winter. When the data finally all come together sometime next year, the team hopes to see a bright ring of light from photons orbiting close to the event horizon, with a dark disk in its center. The ring should be brighter on one side, where the rotation of the black hole gives photons a boost, although the images on this first attempt may not be as crisp as the team's simulations. "It'll probably be a crappy image, but scientifically it will be very interesting," Falcke says. Doeleman hopes to see structure in the matter swirling around the event horizon and watch, movielike, as gas falls into it and vanishes. Such observations might help explain why some black holes gorge on matter and shine brightly, whereas others—like Sgr A*—seem to be on a starvation diet. Falcke has a simpler wish. "The event horizon is the defining thing about a black hole," he says. "I hope to see it; to literally see it."


News Article | February 14, 2017
Site: www.rdmag.com

A new discovery that powerful radio jets from a black hole are stimulating the production of cold gas in the galaxy’s extended halo of hot gas has astronomers surprised. Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) discovered the previously unknown connections between an active galactic nucleus (AGN) and the abundance of cold molecular gas that fuels star birth. “To produce powerful jets, black holes must feed on the same material that the galaxy uses to make new stars,” Michael McDonald, an astrophysicist at the Massachusetts Institute of Technology in Cambridge and coauthor on the paper, said in a statement. “This material powers the jets that disrupt the region and quenches star formation. This illustrates how black holes can slow the growth of their host galaxies.” Normally powerful radio jets from a black hole will suppress star formation but this newly identified supply of cold, dense gas could eventually fuel future star birth as well as feed the black hole itself. The researchers used ALMA to study the galaxy at the heart of the Phoenix Cluster, an uncommonly crowded collection of galaxies about 5.7 billion light-years from Earth. The central galaxy in the cluster harbors a supermassive black hole that is in the process of devouring star-forming gas, which fuels a pair of powerful jets that erupt from the black hole in opposite directions into intergalactic space. Earlier research with NASA’s Chandra X-ray observatory showed that the jets from this AGN are carving out a pair of giant radio bubbles, huge cavities in the hot, diffuse plasma that surrounds the galaxy. The expanding bubbles should create conditions that are too inhospitable for the surrounding hot gas to cool and condense, which are essential steps for future star formation. The astronomers observed long filaments—which extend up to 82,000 light-years from either side of the AGN—of cold molecular gas condensing around the outer edges of the radio bubbles. These filaments collectively contain enough material to make about 10 billion suns. Helen Russell, an astronomer with the University of Cambridge, UK, and lead author on the paper, explained the observation. “With ALMA we can see that there's a direct link between these radio bubbles inflated by the supermassive black hole and the future fuel for galaxy growth,” Russell said in a statement. “This gives us new insights into how a black hole can regulate future star birth and how a galaxy can acquire additional material to fuel an active black hole.” Without a significant source of heat, most massive galaxies in the universe would be forming stars at extreme rates that far exceed observations. The astronomers believe that the heat in the form of radiation and jets from an actively feeding supermassive black hole, prevents overcooling of the cluster’s hot gas atmosphere, suppressing star formation. However, Russell and her team found an additional process that ties the galaxy and its black hole together, where the radio jets that heat the core of the cluster’s hot atmosphere also appear to stimulate the production of the cold gas required to sustain the AGN. “That's what makes this result so surprising,” Brian McNamara, an astronomer at the University of Waterloo, Ontario, and co-author on the paper, said in a statement. “This supermassive black hole is regulating the growth of the galaxy by blowing bubbles and heating the gases around it. “Remarkably, it also is cooling enough gas to feed itself.” The results could help astronomers understand the workings of the cosmic thermostat that controls the launching of radio jets from the supermassive black hole. “This could also explain how the most massive black holes were able to both suppress run-away starbursts and regulate the growth of their host galaxies over the past six billion years or so of cosmic history,” Russell said.


News Article | February 15, 2017
Site: www.eurekalert.org

The Phoenix cluster is an enormous accumulation of about 1,000 galaxies, located 5.7 billion light years from Earth. At its center lies a massive galaxy, which appears to be spitting out stars at a rate of about 1,000 per year. Most other galaxies in the universe are far less productive, squeaking out just a few stars each year, and scientists have wondered what has fueled the Phoenix cluster's extreme stellar output. Now scientists from MIT, the University of Cambridge, and elsewhere may have an answer. In a paper published today in the Astrophysical Journal, the team reports observing jets of hot, 10-million-degree gas blasting out from the central galaxy's black hole and blowing large bubbles out into the surrounding plasma. These jets normally act to quench star formation by blowing away cold gas -- the main fuel that a galaxy consumes to generate stars. However, the researchers found that the hot jets and bubbles emanating from the center of the Phoenix cluster may also have the opposite effect of producing cold gas, that in turn rains back onto the galaxy, fueling further starbursts. This suggests that the black hole has found a way to recycle some of its hot gas as cold, star-making fuel. "We have thought the role of black hole jets and bubbles was to regulate star formation and to keep cooling from happening," says Michael McDonald, assistant professor of physics in MIT's Kavli Institute for Astrophysics and Space Research. "We kind of thought they were one-trick ponies, but now we see they can actually help cooling, and it's not such a cut-and-dried picture." The new findings help to explain the Phoenix cluster's exceptional star-producing power. They may also provide new insight into how supermassive black holes and their host galaxies mutually grow and evolve. McDonald's co-authors include lead author Helen Russell, an astronomer at Cambridge University; and others from the University of Waterloo, the Harvard-Smithsonian Center for Astrophysics, the University of Illinois, and elsewhere. The team analyzed observations of the Phoenix cluster gathered by the Atacama Large Millimeter Array (ALMA), a collection of 66 large radio telescopes spread over the desert of northern Chile. In 2015, the group obtained permission to direct the telescopes at the Phoenix cluster to measure its radio emissions and to detect and map signs of cold gas. The researchers looked through the data for signals of carbon monoxide, a gas that is present wherever there is cold hydrogen gas. They then converted the carbon monoxide emissions to hydrogen gas, to generate a map of cold gas near the center of the Phoenix cluster. The resulting picture was a puzzling surprise. "You would expect to see a knot of cold gas at the center, where star formation happens," McDonald says. "But we saw these giant filaments of cold gas that extend 20,000 light years from the central black hole, beyond the central galaxy itself. It's kind of beautiful to see." The team had previously used NASA's Chandra X-Ray Observatory to map the cluster's hot gas. These observations produced a picture in which powerful jets flew out from the black hole at close to the speed of light. Further out, the researchers saw that the jets inflated giant bubbles in the hot gas. When the team superimposed its picture of the Phoenix cluster's cold gas onto the map of hot gas, they found a "perfect spatial correspondence": The long filaments of frigid, 10-kelvins gas appeared to be draped over the bubbles of hot gas. "This may be the best picture we have of black holes influencing the cold gas," McDonald says. What the researchers believe to be happening is that, as jet inflate bubbles of hot, 10-million-degree gas near the black hole, they drag behind them a wake of slightly cooler, 1-million-degree gas. The bubbles eventually detach from the jets and float further out into the galaxy cluster, where each bubble's trail of gas cools, forming long filaments of extremely cold gas that condense and rain back onto the black hole as fuel for star formation. "It's a very new idea that the bubbles and jets can actually influence the distribution of cold gas in any way," McDonald says. Scientists have estimated that there is enough cold gas near the center of the Phoenix cluster to keep producing stars at a high rate for another 30 to 40 million years. Now that the researchers have identified a new feedback mechanism that may supply the black hole with even more cold gas, the cluster's stellar output may continue for much longer. "As long as there's cold gas feeding it, the black hole will keep burping out these jets," McDonald says. "But now we've found that these jets are making more food, or cold gas. So you're in this cycle that, in theory, could go on for a very long time." He suspects the reason the black hole is able to generate fuel for itself might have something to do with its size. If the black hole is relatively small, it may produce jets that are too weak to completely blast cold gas away from the cluster. "Right now [the black hole] may be pretty small, and it'd be like putting a civilian in the ring with Mike Tyson," McDonald says. "It's just not up to the task of blowing this cold gas far enough away that it would never come back." The team is hoping to determine the mass of the black hole, as well as identify other, similarly extreme starmakers in the universe. PAPER: ALMA observations of massive molecular gas filaments encasing radio bubbles in the Phoenix Cluster http://iopscience. ARCHIVE: Why isn't the universe as bright as it should be? http://news.


News Article | February 23, 2017
Site: www.techtimes.com

Astronomers have long been studying black holes lurking at the center of most galaxies. Scientists have also discovered a great deal of information about them, but no actual photograph of a black hole has yet been produced. Sophisticated telescopes and instruments have allowed scientists to capture images of the sun, asteroids, and surface of other planets and moons, but all scientists have of black holes are mere artist depictions. As their name suggests, black holes are extremely dark object. Black holes are very massive and are known to consume anything that gets across their event horizon including light, which make them so far impossible to photograph. A new telescope network set to be switched on in April later this year, however, could change this and allow humanity to have a glimpse of what a black hole really looks like. The Event Horizon Telescope (EHT) will attempt to capture the first image of a black hole and its event horizon. The telescope will target Sagittarius A*, the monster black hole lurking at the center of the Milky Way. Sagittarius A* is relatively tiny at about 20 million kilometers in diameter. It has 4 million times the solar mass and is 26,000 light-years away from the Earth. EHT, which is consist of several radio telescopes around the world that are linked together, will gather data for 10 days, but the actual image of the black hole would not be available until 2018. The telescopes, which include the Atacama Large Millimeter Array (ALMA), are connected together so they would function like one big scope the size of the Earth. Using a method called Very Long Baseline Interferometry, or VLBI, scientists can combine data from different telescopes scattered around the world in a way it will seem that the black hole is observed by one gigantic telescope. Last year, researchers revealed that because of large gaps in data due to the limited number of telescopes and use of radio wavelengths, which do not produce good pictures, they would have to use an algorithm called Chirp. Chirp would mathematically enhance the radio waves and filter out unwanted data such as atmospheric noise to come up with a more reliable image of the black hole. The algorithm will likewise use other images from space as reference to fill gaps in data. The EHT aims to observe the immediate environment around the black hole, but scientists expect that it would be able to get enough resolution to see the black hole itself. Researchers predict that the black hole will look like a bright ring of light surrounding a dark blob. The light is emitted by gas and dust particles accelerating to high speeds before they are consumed by the black hole. The dark blob, on the other hand, would be the shadow cast over that chaos. "Maybe we can actually see some of the gas flowing around the black hole," said Katie Bouman, from MIT's Computer Science and Artificial Intelligence Laboratory. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.

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