Kavli Institute for Astrophysics and Space Research

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Cambridge, MA, United States
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News Article | February 15, 2017
Site: www.csmonitor.com

An artists rendering of Image issued of hot super-Earth, Gliese 411b, one of the 60 new planets orbiting stars near the Earth's solar system discovered by astronomers at the University of Hertfordshire in Hatfield, England. —How many planets are there? New research is changing the answer – and you could be part of it. From their Hawaii-based observatory, an international team of astronomers observed 1,600 stars for two decades. In the process, they discovered 60 new planets outside our solar system, as well as evidence of 54 more. Chief among them is Gliese 411b, a hot “super-Earth” 8 light years away. These discoveries turn conventional wisdom about planets on its head. Historically, it was assumed that few stars had planets, but it now looks like there could be an almost infinite number of planets beyond our solar system. That, in turn, may affect astronomers’ understanding of how these systems are created. “It is fascinating to think that when we look at the nearest stars, all of them appear to have planets orbiting them. This is something astronomers were not convinced about, even as little as five years ago,” Mikko Tuomi of the University of Hertfordshire’s Centre for Astrophysics Research in Hatfield, England, said in a university press release. “These new planets also help us better understand the formation processes of planetary systems and provide interesting targets for future efforts to image the planets directly.” The Lick-Carnegie Exoplanet Survey, which is responsible for the research, was started in 1996. In the decades since, it has used powerful telescopes like Keck-1, and associated tools, to help scientists study the movement of stars. The recent research is based on almost 61,000 observations of 1,600 stars. Using a technique known as radial velocity to measure tiny changes in the color and location of target stars, the astronomers were able to surmise the presence of planets. That’s how they found Gliese 411b, which orbits the star Gliese 411. Located in the fourth-nearest star system to the sun, it is the third-nearest planetary system to the sun, and has a rocky surface and a mass that is about 40 percent that of the sun. Researchers have dubbed it “super-Earth,” though Dr. Tuomi told Fox News that Gliese 411b is actually too hot to sustain life. To Tuomi, identifying the locations of these planets provides an “observational roadmap” for future study. “This is like mapping an archipelago so that we are familiar with it in the future when taking a closer look at what its islands actually look like,” he told Fox News. For now, Gliese 411b is one of the few planets that scientists have been able to confirm. But could soon change. On Monday, a team led by the Carnegie Institutes of Science that includes researchers from the Massachusetts Institute of Technology in Cambridge, Mass., released the dataset. To make it user-friendly, the data comes along with an open-source software package and an online tutorial on how to process it. Their goal? Encourage people, whoever they are, to look at the data – and hopefully find their own planets. It’s part of a broader move toward crowdsourcing astronomy. “I think this opens up possibilities for anyone who wants to do this kind of work, whether you’re an academic or someone in the general public who’s excited about exoplanets,” Jennifer Burt, a postdoctoral fellow at MIT’s Kavli Institute for Astrophysics and Space Research, told MIT News. “Because really, who doesn’t want to discover a planet?” The research will appear in a forthcoming issue of The Astronomical Journal.


News Article | March 22, 2016
Site: phys.org

Dark Energy Survey image of the region surrounding the faint dwarf galaxy Reticulum II. The nine brightest known stars in the galaxy are marked with red circles. Spectra showing the unique chemical content of three stars are shown. Credit: Alex Ji. Background image: Fermilab/Dark Energy Survey Reticulum II is an ancient and faint dwarf galaxy discovered in images taken as part of the Dark Energy Survey. It orbits the Milky Way galaxy about 100,000 light years away from us. Though the galaxy looks unassuming at first, the chemical content of its stars may hold the key to unlocking a 60-year-old mystery about the cosmic origin of the heaviest elements in the periodic table. Today in the journal Nature, a team of astronomers at MIT's Kavli Institute for Astrophysics and Space Research and the Observatories of the Carnegie Institution of Washington report on observations of this unique galaxy using the Magellan telescopes at the Las Campanas Observatory in Chile's Atacama Desert. Lead author and MIT physics graduate student Alex Ji explains more. Q: How are the heaviest elements in the periodic table created in the cosmos? A: Carl Sagan popularized the notion that we are all made of star stuff. He could say so with confidence because we actually know where nearly every element in the periodic table is made in the universe. But there's a hole in our understanding. The heaviest elements are made in what is called the "rapid neutron-capture process," or "r-process" for short, in which heavy elements are quickly built up from lighter seed nuclei. Gold, platinum, and uranium are r-process elements, as are more exotic elements like europium, neodymium, and gadolinium. The nuclear physics of the r-process was mostly worked out by 1957, but for almost 60 years astronomers have debated about the astrophysical site that could provide the extreme conditions for the r-process to occur. Synthesizing the r-process elements requires environments with a very large number of neutrons. The two best candidate sites are supernovae and merging neutron stars. Supernovae are the explosions that mark the end of a massive star's life. They often leave behind a remnant called a neutron star. During the formation of a neutron star, a large amount of neutrons is released. If two of these neutron stars happen to be orbiting each other, they will eventually merge to form one giant neutron star. During that explosion neutrons are released and r-process elements can form. Q: How does this dwarf galaxy help us understand the site of the r-process? A: Reticulum II is not the first ancient dwarf galaxy to have its chemical content examined; it's actually the 10th. But its chemical composition differs completely from those other galaxies. The stars in those first nine galaxies have unusually low amounts of r-process elements. Reticulum II, on the other hand, is chock-full of r-process elements. Its stars display some of the highest r-process enhancements we have ever seen. It's almost literally a gold mine. What this means is that a single rare event produced a rather large amount of this r-process material. All those elements were then incorporated into the surrounding gas and from there into the next generations of stars. It is those stars that we can still observe today. The single, prolific r-process event in this galaxy implies that a neutron star merger could have produced these elements in the early universe. A normal supernova would have produced less, and the observed enhancement could not have been as high, though it's also hypothesized that rare, magnetically-driven supernovae might be able to produce much more r-process material. Interestingly, there is indirect evidence that neutron star mergers do also synthesize r-process elements in the universe today. So it looks like neutron star mergers could be the primary r-process sites throughout cosmic time. It's amazing to think that Reticulum II preserved a signature of that extraordinary event for more than 12 billion years, just waiting for us to dig it up. Q: What was it like to be at the telescope and realize what you had found? A: Based on studying the other ultra-faint galaxies, I had expected to find stars with essentially none of these r-process elements and to further establish that these types of dwarf galaxies are devoid in these elements. So we had a plan to get some really good, low upper limits on the r-process content to push this issue. When we realized the stars in this galaxy were the complete opposite, and instead full of r-process elements, I was certain I had screwed something up. From the telescope in Chile I called my advisor Anna Frebel in Cambridge [Mass.] in the middle of the night to urgently talk about what was going on. Telescope time is precious and expensive after all and shouldn't be wasted. During the hour-long discussions that followed, I kept observing more stars while carrying out preliminary analyses of the data at hand to ensure that this was a real signal. At the observatory, astronomers work all night and sleep during the day. But after seeing the r-process elements in the first few stars, I couldn't sleep anymore; all I could do was stare out the window and hope the incoming clouds would go away again and the wind would die down. We were very lucky that it ended up being clear most of the four nights we had available. My last night there, the weather forecast, as translated from Spanish by Google, read "rain and wind." So I prepared myself to get no data that night. But it turned out Google had translated the word "despejado" incorrectly and in fact it was supposed to be "clear and wind." An important translation to get right, especially for astronomers! More information: Alexander P. Ji et al. R-process enrichment from a single event in an ancient dwarf galaxy, Nature (2016). DOI: 10.1038/nature17425


News Article | February 13, 2017
Site: www.rdmag.com

The search for planets beyond our solar system is about to gain some new recruits. Today, a team that includes MIT and is led by the Carnegie Institution for Science has released the largest collection of observations made with a technique called radial velocity, to be used for hunting exoplanets. The huge dataset, taken over two decades by the W.M. Keck Observatory in Hawaii, is now available to the public, along with an open-source software package to process the data and an online tutorial. By making the data public and user-friendly, the scientists hope to draw fresh eyes to the observations, which encompass almost 61,000 measurements of more than 1,600 nearby stars. “This is an amazing catalog, and we realized there just aren’t enough of us on the team to be doing as much science as could come out of this dataset,” says Jennifer Burt, a Torres Postdoctoral Fellow in MIT’s Kavli Institute for Astrophysics and Space Research. “We’re trying to shift toward a more community-oriented idea of how we should do science, so that others can access the data and see something interesting.” Burt and her colleagues have outlined some details of the newly available dataset in a paper to appear in The Astrophysical Journal. After taking a look through the data themselves, the researchers have detected over 100 potential exoplanets, including one orbiting GJ 411, the fourth-closest star to our solar system. “There seems to be no shortage of exoplanets,” Burt says. “There are a ton of them out there, and there is ton of science to be done.” The newly available observations were taken by the High Resolution Echelle Spectrometer (HIRES), an instrument mounted on the Keck Observatory’s 10-meter telescope at Mauna Kea in Hawaii. HIRES is designed to split a star’s incoming light into a rainbow of color components. Scientists can then measure the precise intensity of thousands of color channels, or wavelengths, to determine characteristics of the starlight. Early on, scientists found they could use HIRES’ output to estimate a star’s radial velocity — the very tiny movements a star makes either as a result of its own internal processes or in response to some other, external force. In particular, scientists have found that when a star moves toward and away from Earth in a regular pattern, it can signal the presence of an exoplanet orbiting the star. The planet’s gravity tugs on the star, changing the star’s velocity as the planet moves through its orbit. “[HIRES] wasn’t specifically optimized to look for exoplanets,” Burt says. “It was designed to look at faint galaxies and quasars. However, even before HIRES was installed, our team worked out a technique for making HIRES an effective exoplanet hunter.” For two decades, these scientists have pointed HIRES at more than 1,600 “neighborhood” stars, all within a relatively close 100 parsecs, or 325 light years, from Earth. The instrument has recorded almost 61,000 observations, each lasting anywhere from 30 seconds to 20 minutes, depending on how precise the measurements needed to be. With all these data compiled, any given star in the dataset can have several days’, years’, ore even more than a decade’s worth of observations. “We recently discovered a six-planet system orbiting a star, which is a big number,” Burt says. “We don’t often detect systems with more than three to four planets, but we could successfully map out all six in this system because we had over 18 years of data on the host star.” More eyes on the skies Within the newly available dataset, the team has highlighted over 100 stars that are likely to host exoplanets but require closer inspection, either with additional measurements or further analysis of the existing data. The researchers have, however, confirmed the presence of an exoplanet around GJ 411, which is the fourth-closest star to our solar system and has a mass that is roughly 40 percent that of our sun. The planet has an extremely tight orbit, circling the star in less than 10 days. Burt says that there is a good chance that others, looking through the dataset and combining it with their own observations, may find similarly intriguing candidates. “We’ve gone from the early days of thinking maybe there are five or 10 other planets out there, to realizing almost every star next to us might have a planet,” Burt says. HIRES will continue to record observations of nearby stars in the coming years, and the team plans to periodically update the public dataset with those observations. “This dataset will slowly grow, and you’ll be able to go on and search for whatever star you’re interested in and download all the data we’ve ever taken on it. The dataset includes the date, the velocity we measured, the error on that velocity, and measurements of the star’s activity during that observation,” Burt says. “Nowadays, with access to public analysis software like Systemic, it’s easy to load the data in and start playing with it.” Then, Burt says, the hunt for exoplanets can really take off. “I think this opens up possibilities for anyone who wants to do this kind of work, whether you’re an academic or someone in the general public who’s excited about exoplanets,” Burt says. “Because really, who doesn’t want to discover a planet?” This research was supported, in part, by the National Science Foundation.


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

The search for planets beyond our solar system is about to gain some new recruits. Today, a team that includes MIT and is led by the Carnegie Institution for Science has released the largest collection of observations made with a technique called radial velocity, to be used for hunting exoplanets. The huge dataset, taken over two decades by the W.M. Keck Observatory in Hawaii, is now available to the public, along with an open-source software package to process the data and an online tutorial. By making the data public and user-friendly, the scientists hope to draw fresh eyes to the observations, which encompass almost 61,000 measurements of more than 1,600 nearby stars. "This is an amazing catalog, and we realized there just aren't enough of us on the team to be doing as much science as could come out of this dataset," says Jennifer Burt, a Torres Postdoctoral Fellow in MIT's Kavli Institute for Astrophysics and Space Research. "We're trying to shift toward a more community-oriented idea of how we should do science, so that others can access the data and see something interesting." Burt and her colleagues have outlined some details of the newly available dataset in a paper to appear in The Astrophysical Journal. After taking a look through the data themselves, the researchers have detected over 100 potential exoplanets, including one orbiting GJ 411, the fourth-closest star to our solar system. "There seems to be no shortage of exoplanets," Burt says. "There are a ton of them out there, and there is ton of science to be done." The newly available observations were taken by the High Resolution Echelle Spectrometer (HIRES), an instrument mounted on the Keck Observatory's 10-meter telescope at Mauna Kea in Hawaii. HIRES is designed to split a star's incoming light into a rainbow of color components. Scientists can then measure the precise intensity of thousands of color channels, or wavelengths, to determine characteristics of the starlight. Early on, scientists found they could use HIRES' output to estimate a star's radial velocity -- the very tiny movements a star makes either as a result of its own internal processes or in response to some other, external force. In particular, scientists have found that when a star moves toward and away from Earth in a regular pattern, it can signal the presence of an exoplanet orbiting the star. The planet's gravity tugs on the star, changing the star's velocity as the planet moves through its orbit. "[HIRES] wasn't specifically optimized to look for exoplanets," Burt says. "It was designed to look at faint galaxies and quasars. However, even before HIRES was installed, our team worked out a technique for making HIRES an effective exoplanet hunter." For two decades, these scientists have pointed HIRES at more than 1,600 "neighborhood" stars, all within a relatively close 100 parsecs, or 325 light years, from Earth. The instrument has recorded almost 61,000 observations, each lasting anywhere from 30 seconds to 20 minutes, depending on how precise the measurements needed to be. With all these data compiled, any given star in the dataset can have several days', years', ore even more than a decade's worth of observations. "We recently discovered a six-planet system orbiting a star, which is a big number," Burt says. "We don't often detect systems with more than three to four planets, but we could successfully map out all six in this system because we had over 18 years of data on the host star." Within the newly available dataset, the team has highlighted over 100 stars that are likely to host exoplanets but require closer inspection, either with additional measurements or further analysis of the existing data. The researchers have, however, confirmed the presence of an exoplanet around GJ 411, which is the fourth-closest star to our solar system and has a mass that is roughly 40 percent that of our sun. The planet has an extremely tight orbit, circling the star in less than 10 days. Burt says that there is a good chance that others, looking through the dataset and combining it with their own observations, may find similarly intriguing candidates. "We've gone from the early days of thinking maybe there are five or 10 other planets out there, to realizing almost every star next to us might have a planet," Burt says. HIRES will continue to record observations of nearby stars in the coming years, and the team plans to periodically update the public dataset with those observations. "This dataset will slowly grow, and you'll be able to go on and search for whatever star you're interested in and download all the data we've ever taken on it. The dataset includes the date, the velocity we measured, the error on that velocity, and measurements of the star's activity during that observation," Burt says. "Nowadays, with access to public analysis software like Systemic, it's easy to load the data in and start playing with it." Then, Burt says, the hunt for exoplanets can really take off. "I think this opens up possibilities for anyone who wants to do this kind of work, whether you're an academic or someone in the general public who's excited about exoplanets," Burt says. "Because really, who doesn't want to discover a planet?" This research was supported, in part, by the National Science Foundation. ARCHIVE: New exoplanet in our neighborhood http://news.


News Article | February 15, 2017
Site: phys.org

Today, a team that includes MIT and is led by the Carnegie Institution for Science has released the largest collection of observations made with a technique called radial velocity, to be used for hunting exoplanets. The huge dataset, taken over two decades by the W.M. Keck Observatory in Hawaii, is now available to the public, along with an open-source software package to process the data and an online tutorial. By making the data public and user-friendly, the scientists hope to draw fresh eyes to the observations, which encompass almost 61,000 measurements of more than 1,600 nearby stars. "This is an amazing catalog, and we realized there just aren't enough of us on the team to be doing as much science as could come out of this dataset," says Jennifer Burt, a Torres Postdoctoral Fellow in MIT's Kavli Institute for Astrophysics and Space Research. "We're trying to shift toward a more community-oriented idea of how we should do science, so that others can access the data and see something interesting." Burt and her colleagues have outlined some details of the newly available dataset in a paper to appear in the Astrophysical Journal. After taking a look through the data themselves, the researchers have detected over 100 potential exoplanets, including one orbiting GJ 411, the fourth-closest star to our solar system. "There seems to be no shortage of exoplanets," Burt says. "There are a ton of them out there, and there is ton of science to be done." The newly available observations were taken by the High Resolution Echelle Spectrometer (HIRES), an instrument mounted on the Keck Observatory's 10-meter telescope at Mauna Kea in Hawaii. HIRES is designed to split a star's incoming light into a rainbow of color components. Scientists can then measure the precise intensity of thousands of color channels, or wavelengths, to determine characteristics of the starlight. Early on, scientists found they could use HIRES' output to estimate a star's radial velocity—the very tiny movements a star makes either as a result of its own internal processes or in response to some other, external force. In particular, scientists have found that when a star moves toward and away from Earth in a regular pattern, it can signal the presence of an exoplanet orbiting the star. The planet's gravity tugs on the star, changing the star's velocity as the planet moves through its orbit. "[HIRES] wasn't specifically optimized to look for exoplanets," Burt says. "It was designed to look at faint galaxies and quasars. However, even before HIRES was installed, our team worked out a technique for making HIRES an effective exoplanet hunter." For two decades, these scientists have pointed HIRES at more than 1,600 "neighborhood" stars, all within a relatively close 100 parsecs, or 325 light years, from Earth. The instrument has recorded almost 61,000 observations, each lasting anywhere from 30 seconds to 20 minutes, depending on how precise the measurements needed to be. With all these data compiled, any given star in the dataset can have several days', years', ore even more than a decade's worth of observations. "We recently discovered a six-planet system orbiting a star, which is a big number," Burt says. "We don't often detect systems with more than three to four planets, but we could successfully map out all six in this system because we had over 18 years of data on the host star." More eyes on the skies Within the newly available dataset, the team has highlighted over 100 stars that are likely to host exoplanets but require closer inspection, either with additional measurements or further analysis of the existing data. The researchers have, however, confirmed the presence of an exoplanet around GJ 411, which is the fourth-closest star to our solar system and has a mass that is roughly 40 percent that of our sun. The planet has an extremely tight orbit, circling the star in less than 10 days. Burt says that there is a good chance that others, looking through the dataset and combining it with their own observations, may find similarly intriguing candidates. "We've gone from the early days of thinking maybe there are five or 10 other planets out there, to realizing almost every star next to us might have a planet," Burt says. HIRES will continue to record observations of nearby stars in the coming years, and the team plans to periodically update the public dataset with those observations. "This dataset will slowly grow, and you'll be able to go on and search for whatever star you're interested in and download all the data we've ever taken on it. The dataset includes the date, the velocity we measured, the error on that velocity, and measurements of the star's activity during that observation," Burt says. "Nowadays, with access to public analysis software like Systemic, it's easy to load the data in and start playing with it." Then, Burt says, the hunt for exoplanets can really take off. "I think this opens up possibilities for anyone who wants to do this kind of work, whether you're an academic or someone in the general public who's excited about exoplanets," Burt says. "Because really, who doesn't want to discover a planet?"


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.


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.


News Article | July 6, 2016
Site: www.techtimes.com

The Hitomi spacecraft was designed to discover the presence of black holes, but the vehicle malfunctioned soon after launch. The Japanese-designed space-based observatory was unable to complete its primary mission, but mission engineers now know what the spacecraft saw just prior to its untimely demise. The Perseus Cluster is a tremendous grouping of thousands of galaxies, stretching 2 million light-years across, making it one of the massive objects seen anywhere in the observable Universe. Data recovered from Hitomi show a surprising discovery concerning this body. The gas within the center of the cluster was seen traveling significantly slower than astronomers had predicted. Despite this lack of energy, the center of the cluster is home to a massive black hole, which normally would add to the total kinetic motion within such a structure — astronomers think this is puzzling. "You'd expect the gas in this region to be quite stirred up, but it's not. It's really kind of quiet compared to how much disorder we see coming from the black hole," said Eric Miller from the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT). Hitomi, developed by the Japanese space agency JAXA and NASA, was launched into space in February. The X-ray observatory was designed to record some of the most powerful events in the universe. The spacecraft would have examined galaxy clusters, supermassive black holes, and stars as they underwent explosive deaths. These highly energetic events result in the emission of vast amounts of X-rays, which can be detected by satellites orbiting Earth. The Perseus Cluster, the first scheduled target for Hitomi, sits 250 million light-years from our own world. For roughly one month, the vehicle recorded X-rays from the galaxy cluster. The presence of iron and hydrogen was recorded within the massive structure. These observations can provide astronomers with the data they need to determine the average temperature within such a cosmic structure. Following its brief foray studying the cluster, the spacecraft began to tumble out of control. Solar panels, which were the only source of power for the spacecraft, were jettisoned as the vehicle somersaulted out of control, dooming the mission. Soon after, controllers lost contact with the observatory. Hitomi was designed to operate for three years as it studied some of the most energetic events in the universe. Efforts to salvage the mission were called off on April 28. Analysis of the data recorded by the Hitomi spacecraft before the loss of the vehicle was detailed in the journal Nature. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.


News Article | November 17, 2015
Site: www.techtimes.com

Astronomers have discovered a rocky planet that is orbiting a small star that has many similarities to Earth and Venus. Back in May, a team of researchers using the MEarth-South telescope at the Cerro Tololo Inter-American Observatory in Chile identified the the exoplanet named GJ 1132b that is only about 39 light-years away, making it the closest exoplanet that has yet to be discovered. Published recently in the journal Nature, astrophysicists from MIT and other astronomers found that GJ 1132b is only 1.2 times the size of the Earth, has a mass about 1.6 times that of the Earth, and orbits a parent star. It takes 1.6 days for it take make a single trip around the red dwarf Gliese 1132. Just like the moon's tides are locked to our planet, the Earth-sized exoplanet also is tidally locked, which simply means it has a day and a night side, depending on which side is facing its star while in orbit. There is no denying GJ 1132b's similarities to the Earth, but it can actually pass as a cousin to another planet in our solar system, Venus. The planet orbits very close it its parent star, giving it a surface temperature much hotter than Earth's at about 440 degrees Fahrenheit. "Our ultimate goal is to find a twin Earth, but along the way we've found a twin Venus," astronomer David Charbonneau of the Harvard-Smithsonian Center for Astrophysics (CfA) said in a statement. "We suspect it will have a Venus-like atmosphere, too, and if it does we can't wait to get a whiff." While GJ 1132b is even hotter than Venus, researchers will be able to use telescopes to measure the amount of light that passes through the GJ 1132b's atmosphere, which can then be analyzed for atmospheric gases like oxygen that could give clues the alien life. But don't get too excited because the planet is even hotter than Venus, and is too close to its star for it to contain liquid water. "The temperature of the planet is about as hot as your oven will go, so it's like burnt-cookie hot," said Zachory Berta-Thompson, a postdoc in MIT's Kavli Institute for Astrophysics and Space Research. "It's too hot to be habitable—there's no way there's liquid water on the surface. But it is a lot cooler than the other rocky planets that we know of." Researchers will conduct an in-depth study of the exoplanet that has Earth and Venus-like characteristics using the Hubble Space Telescope in 2018.


News Article | November 12, 2015
Site: www.techtimes.com

Astronomers say a newly discovered planet almost next door to us — just 39 light-years away — is the closest rocky exoplanet like Earth ever found. It's not like Earth in one respect, though: the atmosphere in its coolest parts is a sizzling 450 to 500 degrees Fahrenheit, making it more like our solar system neighbor Venus than our own world, scientists say. Still, the planet's proximity to us and its resemblance to Earth in at least its diameter and mass make it "arguably the most important planet ever found outside the solar system," Drake Demming of the University of Maryland wrote in a commentary accompanying the published study on the discovery. Just 16 percent larger than Earth, the planet GJ 1132b orbits a dim star just one-fifth the size of our sun. It's close to its parent star, orbiting at just 1.4 million miles away. For comparison, Mercury in our solar system orbits our sun at 36 million miles. At just 39 light-years away, its parent star, Gliese 1132, is a close neighbor in the Milky Way. "Our galaxy spans about 100,000 light-years," said Zachory Berta-Thompson, a postdoctoral researcher at MIT's Kavli Institute for Astrophysics and Space Research. "So this is definitely a very nearby solar neighborhood star." The planet GJ 1132b is probably tidally locked in its orbit, which means it always presents the same face to its star, creating a permanent and unchanging day and night side. Because of its sizzling temperature, it's unlikely to retain liquid water on its surface, making it almost certainly uninhabitable, the scientists say. Still, it's cool enough to have retained a significant atmosphere, they point out, which makes it an interesting subject for study. "If we find this pretty hot planet has managed to hang onto its atmosphere over the billions of years it's been around, that bodes well for the long-term goal of studying cooler planets that could have life," explained Berta-Thompson. Its nearness provides an unprecedented opportunity to make observations, since most Earth-sized planets discovered so far are thousands of light-years distant from us. "We finally have a target to point our telescopes at, and [can] dig much deeper into the workings of a rocky exoplanet, and what makes it tick," Berta-Thompson said. While it may be more like Venus than the Earth, it will allow scientists to test theories about rocky planets, how they form, how they end up in their particular orbits and what physical process takes place on their surfaces. "Our ultimate goal is to find a twin Earth, but along the way we've found a twin Venus," said astronomer David Charbonneau of the Harvard-Smithsonian Center for Astrophysics. "We suspect it will have a Venus-like atmosphere too, and if it does we can't wait to get a whiff."

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