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News Article | April 19, 2017
Site: news.yahoo.com

An artist’s impression shows a super-Earth passing across the disk of the faint red star known as LHS 1140. (CfA Illustration / M. Weiss) It’s not the closest potentially habitable planet, but astronomers say a world 40 percent wider than Earth could be one of the best places to target in the search for life beyond our solar system. “This is the most exciting exoplanet I’ve seen in the past decade. We could hardly hope for a better target to perform one of the biggest quests in science – searching for evidence of life beyond Earth,” Jason Dittmann, an astronomer at the Harvard-Smithsonian Center for Astrophysics, said today in a news release. Dittmann is the lead author of a paper published by the journal Nature describing the exoplanet, known as LHS 1140 b. The super-Earth orbits a star dubbed LHS 1140, 40 light-years from Earth in the southern constellation Cetus. The planet was discovered in 2014 with the MEarth-South telescope array at Cerro Tololo Inter-American Observatory in Chile, using a method that measured the faint dimming of starlight as it passed across LHS 1140’s disk. An analysis of the resulting data determined that the planet orbits the star every 25 days, at a distance well within Mercury’s orbit around our own sun (roughly 7.4 million miles). But because LHS 1140 b is so much dimmer than our sun, the planet is thought to be in a habitable zone where water can exist in liquid form. Further observations from the High Accuracy Radial-velocity Planet Searcher, or HARPS, led the researchers to estimate the planet’s mass at 6.6 times that of Earth. That suggests the planet is dense enough to be rocky. Over the past year, other astronomers have detected potentially habitable exoplanets that are closer, including Proxima Centauri b and the TRAPPIST-1 worlds. Those worlds, however, present challenges for further study. Proxima Centauri b may be a mere 4.2 light-years from Earth, but scientists suspect that it doesn’t make a transit across its parent star. That would rule out the prospect of analyzing how starlight is altered as it passes through any atmosphere – which is currently considered the leading strategy for hunting down signs of habitability and alien life. The seven known planets in the TRAPPIST-1 system make transits, which fortunately allows for further study. But some scientists worry that the system’s young red dwarf star is so active that high-energy radiation has sterilized any environment where life might otherwise exist. The star LHS 1140 is also a red dwarf, but it’s old enough to have settled down. “The present conditions of the red dwarf are particularly favorable – LHS 1140 spins more slowly and emits less high-energy radiation than other similar low-mass stars,” said the Geneva Observatory’s Nicola Astudillo-Defru, a co-author of the Nature study. He and his fellow researchers say LHS 1140 b’s atmosphere might have weathered the star’s early outbursts due to the planet’s size, and the fact that it was probably farther away from the star back then. As the planet heated up, a steaming ocean of lava conceivably provided water vapor to replenish the atmosphere. For now, much of the speculation about the planet’s atmosphere is little more than hand-waving. “Right now we’re just making educated guesses about the content of this planet’s atmosphere,” Dittmann acknowledged. “Future observations might enable us to detect the atmosphere of a potentially habitable planet for the first time. We plan to search for water, and ultimately molecular oxygen.” First, astronomers will use the Hubble Space Telescope to gauge more precisely how much high-energy radiation LHS 1140 b is currently getting, Then they’ll turn to NASA’s James Webb Space Telescope, which is due for launch next year. The European Southern Observatory’s Extremely Large Telescope in Chile, scheduled to enter service in the mid-2020s, could also be employed in the quest. Dittmann and Astudillo-Defru are among 24 authors of the Nature study, titled “A Temperate Rocky Super-Earth Transiting a Nearby Cool Star.”


News Article | May 1, 2017
Site: phys.org

An image of the colliding galaxies known as The Antennae, taken in the optical and near-infrared. Astronomers using the ALMA submillimeter array have found evidence for shocked gas near the nucleus of the northern (upper) galaxy, and argue that it is due to material infalling onto the nuclear region. Credit: ESA/Hubble & NASA Collisions between galaxies, especially ones rich in molecular gas, can trigger bursts of star formation that heat the dust and result in their shining brightly in the infrared. Astronomers think that there is also significant gas inflowing to the central regions of galaxies that can stimulate starburst activity. Inflowing gas, as it collides with the gas in the inner regions, should produce powerful shocks that should make the gas itself glow. Some evidence for gas inflows on galactic scales has been discovered, but there have been few observational confirmations of the effects of the inflowing material in the inner region of the galactic nucleus. CfA astronomers Junko Ueda, David Wilner, and Giovanni Fazio used the ALMA submillimeter array to study the gas in the central regions of the Antennae galaxies, the nearest mid-stage merging system (about seventy-two million light-years away). The star formation rate of the system is estimated to be about ten solar-masses per year, much of it in the off-nuclear region (the so-called "overlap region") of the two galaxies; the two nuclear regions themselves appear to have lower star formation rates. The astronomers examined the star formation in one of the two nuclear regions, whose gas abundance is as much as one hundred times more than in the Milky Way's center. They measured the emission from five organic molecules, CN, HCN, HCO+, CH3OH (methanol), and HNCO (isocyanic acid), looking for evidence of shock activity. And they found it. The methanol and isocyanic acid in particular were detected, for the first time in this object, and show clear evidence ion their intensities, ratios, and velocities for being excited by shocks. The evidence from the geometry of the emission suggests that the shocks are produced by infall, rather than from the collision. However, there is also the possibility that the induced burst of star formation produced local shocks that contributed to the shock activity. Although further work is needed, the results so far indicate that infalling material is likely responsible. More information: Junko Ueda et al. ALMA observations of the dense and shocked gas in the nuclear region of NGC 4038 (Antennae galaxies), Publications of the Astronomical Society of Japan (2017). DOI: 10.1093/pasj/psw110


News Article | April 19, 2017
Site: www.cnet.com

Exoplanet discoveries in the past decade have made it clear there are plenty of other solar systems, but in the last year we've increasingly spotted new worlds that indicate there may be plenty of other Earths out there too. On Wednesday, a newly discovered and relatively nearby planet vaulted toward the top of the growing list of exoplanets worth a closer look for signs of alien creepy-crawlies or ... who knows? The planet orbits a faint red dwarf star named LHS 1140 just 40 light-years away in the constellation Cetus, named after the sea monster. Astronomers say it's larger than Earth, but appears to be rocky and temperate and likely has an atmosphere. "This is the most exciting exoplanet I've seen in the past decade," said Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics (CfA). He's also lead author of a paper on the discovery (PDF link) to be published in Thursday's issue of the journal Nature. "We could hardly hope for a better target to perform one of the biggest quests in science -- searching for evidence of life beyond Earth." This latest discovery comes within a year of the revelation that the nearest star beyond our sun, Proxima Centauri, is also orbited by an Earth-size planet, and less than two months after we learned the Trappist-1 system boasts a whopping seven such planets. The prospects for spotting signs of life on super-Earth LHS 1140-b are even better, because unlike with Proxima b, we're aligned at a nearly perfect angle to observe it as it passes in front of its star every 25 days. Proxima Centauri, Trappist-1 and LHS 1140 are all dwarf stars, which means daylight on any orbiting planets is likely a little more dim than on Earth. A problem with these smaller stars is that they tend to blast their systems with frequent flares of radiation in the earlier part of their lives. Part of what has scientists so excited about LHS 1140 is that it spends less energy sterilizing its neighborhood than Trappist-1. "The present conditions of the red dwarf are particularly favorable -- LHS 1140 spins more slowly and emits less high-energy radiation than other similar low-mass stars," team member Nicola Astudillo-Defru from the Geneva Observatory explained in a statement. Even if LHS 1140 released a lot of radiation earlier in its existence, researchers point to the fact that the nearby super-Earth is so large and dense -- its diameter is 40 percent more than our planet and it's 6.6 times more massive -- as evidence it may have been able to defend itself when the star was younger and more prone to flare-ups. They say its large size indicates an ocean of lava could have roiled on its surface for millions of years, feeding a radiation-blocking atmosphere with steam. That cycle could preserve water on the planet, enhancing its potential to host life. "Right now we're just making educated guesses about the content of this planet's atmosphere," Dittmann said. "Future observations might enable us to detect the atmosphere of a potentially habitable planet for the first time. We plan to search for water, and ultimately molecular oxygen." Plans are already in place to observe the system with NASA's Hubble Space Telescope to try and discern just how much radiation is being showered upon LHS 1140-b. It's also likely to be a prime target for next-generation telescopes scheduled to begin coming online next year. "This planet will be an excellent target for the James Webb Space Telescope when it launches in 2018, and I'm especially excited about studying it with the ground-based Giant Magellan Telescope, which is under construction," said co-author David Charbonneau of the CfA. Of course, if these discoveries keep coming at us so quickly, it will be one of many targets by that time. Fortunately, next-generation telescopes are built in such a way that they aren't susceptible to whiplash. CNET en Español: Get all your tech news and reviews in Spanish.


News Article | April 17, 2017
Site: phys.org

An image of a region with both star-forming cores (seen in the red) and starless clumps (the dark regions). Astronomers have combined statistical studies of these infrared data with submillimeter images to estimate the typical age of a massive star forming clump as about one million years. The red data are from Herschel 70 micron images, the green and blue are from Spitzer IRAC images at 8 and 4.5 microns. Credit: Battersby et al. Astronomers can roughly estimate how long it takes for a new star to form: it is the time it takes for material in a gas cloud to collapse in free-fall, and is set by the mass, the size of the cloud, and gravity. Although an approximation, this scenario of quick, dynamic star formation is consistent with many observations, especially of sources where new material can flow into the cloud, perhaps along filaments, to sustain steady activity. But this simple picture might not apply in the largest systems with star clusters and high-mass stars. Rather than a quick collapse, the process there might be inhibited by pressure, turbulence, or other activities that slow it down. CfA astronomer Cara Battersby and two colleagues studied the formation, early evolution, and lifetimes of high-mass star-forming regions and their earliest evolutionary phases in dense, molecular regions. These clumps have densities of gas as high as ten million molecules per cubic centimeter (tens of thousands of times higher than typical in gas clouds); the dust associated with this gas blocks the external starlight, leaving the material very cold, only a few tens of degrees above absolute zero. The usual method for identifying these clumps is with submillimeter telescopes, which take images of the sky; automated algorithms can then process the images to identify and characterize cold clumps. The problem is that even a quiescent clump can contain subregions of activity that are not spotted with the relatively poor spatial resolutions of the submillimeter telescopes used to assemble catalogs of these regions. Rather than rely on the submillimeter images of the entire clumps, the astronomers examined each of the multiple, individual pixels in each clump image and compared the results with data from infrared and far infrared. These infrared images sample hotter material, including that from small embedded sources that may have been overpowered in the larger image. The infrared signals the presence of star formation activity in the clump, and also characterizes the dust temperatures (which are slightly higher when such activity is present). The authors anchor their timeframe to sources called methanol masers, found in star forming regions, which last for about 35,000 years. These masers are seen in many of the dense clumps, and reasonable estimates of their properties constrain the ages of the clumps in which they are located. The statistics from all the submillimeter and infrared clumps then provides an estimate of the typical values of a clump lifetime. The astronomers find that clumps without any embedded stars last between about 0.2 and 1.7 million years, while those with stars last only about half that time. The times, in the star formation case, span a range from about 0.4 - 2.4 free-fall times, in good agreement with the models. The results also demonstrate that most high density gas is found in clumps lacking a high-mass star (however, there could be small, low-mass stars present). Explore further: The properties of pre-stellar cores More information: Cara Battersby et al. The Lifetimes of Phases in High-mass Star-forming Regions, The Astrophysical Journal (2017). DOI: 10.3847/1538-4357/835/2/263


News Article | May 22, 2017
Site: phys.org

A false-color image map of the gas density in the Musca star-forming filament (the highest densities are shown in red). New theoretical work on the structure of these long filaments proposes several kinds of star-forming zones along the length and successfully reproduces many of the features seen in filaments like this one in Musca. Credit: Kainulainen, 2016 Interstellar molecular clouds are often seen to be elongated and "filamentary" in shape, and come in a wide range of sizes. In molecular clouds, where stars form, the filamentary structure is thought to play an important role in star formation as the matter collapses to form protostars. Filamentary clouds are detected because the dust they contain obscures the optical light of background stars while emitting at infrared and submillimeter wavelengths. Observations of some filaments indicate that they are themselves composed of bundles of closely spaced fibers with distinct physical properties. Computer simulations are able to reproduce some of these filamentary structures, and astronomers generally agree that turbulence in the gas combined with gravitational collapse can lead to filaments and protostars within them, but the exact ways in which filaments form, make stars, and finally dissipate are not understood. The number of new stars that develop, for example, varies widely between filaments for reasons that are not known. The usual model for a star forming filament is a cylinder whose density increases towards the axis according to a specific profile, but which otherwise is uniform along its length. CfA astronomer Phil Myers has developed a variant of this model in which the filament has a star-forming zone along its length where the density and diameter are higher, with three generic profiles to describe their shapes. Besides being a more realistic description of a filament's structure, the different density profiles develop different strength gravitational "wells" naturally leading to different numbers of stars forming within them. Myers compares the star formation properties of these three kinds of zones with the properties of observed star formation filaments, with excellent results. The filament in the molecular cloud in Musca has relatively little star formation, and can be reasonably well explained with one of the three profiles indicative of an early stage of evolution. A small cluster of young stars in the Corona Australis constellation fits a second model that has evolved for longer, while Ophiuchus hosts a filament that may be near the end of its star forming lifetime and resembles the third type. The three profiles so far seem able to account for the full range of conditions. The new results are an important step in bringing more sophistication and realism to the theory of star forming filaments. Future work will probe the specific processes that fragment the various star-forming zones into their stars. Explore further: The lifetimes of massive star-forming regions More information: Philip C. Myers. Star-forming Filament Models, The Astrophysical Journal (2017). DOI: 10.3847/1538-4357/aa5fa8


News Article | May 16, 2017
Site: phys.org

(right) A consolidated image of distant massive galaxies detected in the X-ray by Chandra and (left) as imaged in the infrared with Spitzer. A new study of similar galaxies whose central active black hole nucleus is obscured has concluded that accreting streams of material into the galaxy produces a more compact central region. Credit: NASA/CXC/Durham/D.Alexander et al Most if not all galaxies are thought to host a supermassive black hole in their nuclei. It grows by accreting mass, and while feeding it is not hidden from our view: it generates X-ray emission and ultraviolet that heats the dust which in turn radiates in the infrared. During the evolutionary phase in which it is most active, the object is known as an active galactic nucleus (AGN). The vast majority of AGN reside in normal galaxies in which the activity of star formation co-evolves with the black hole accretion, but astronomers disagree about the nature of the host galaxies, and in particular whether they resemble normal star forming galaxies in their overall structure. The main problem lies in the difficulty of distinguishing the contribution the AGN makes to the emission from that of the host galaxy. Even images from the Hubble Space Telescope are unable to distinguish the nuclear component when there is significant dust obscuration in the galaxy. These so-called "obscured AGN" contribute only weakly to the optical emission since it is absorbed by the dust. However, the ones studied to date are extremely luminous overall, with among the largest total luminosities known, equivalent to more than ten billion Suns. CfA astronomers Francesca Civano and Stefano Marchesi and their colleagues prepared a precisely defined sample of obscured AGN—those whose infrared emission is more than twenty times larger than its X-ray emission (the X-ray emission was measured by the Chandra X-ray Observatory). They first collected a set of 265 AGN and then determined which ones were "obscured" by calculating the infrared emission of each to ratio with its X-ray emission. They did this by assembling the full spectral distribution of the radiation, combining infrared with UV and optical data and then modeling the entire distribution to determine the total infrared component from the AGN alone with a code that models and subtracts the contributions from stars and other processes. Once they had the infrared value, they could tell which ones qualified as "obscured." Their final sample of obscured AGN had 182 objects. They next analyzed the very faint optical images of the nuclear regions of this set by combining them all into a composite image, and found that the nuclear region in this generic image was unusually compact in angular size, more than twice as small as the corresponding regions in star formation galaxies. The scientists argue that these obscured AGN must have undergone a process of contraction perhaps, as suggested by some simulations, when cold streams of gas flow into the galaxy and drive material to the nucleus, making them compact. The results are significant not only because they help to clarify what is happening in this class of X-ray bright AGN, but also because something like this process seems to be underway in galaxies in the early universe which have the appearance of also being unusually compact. Explore further: Into the submillimeter—the early universe's formation More information: Yu-Yen Chang et al. Obscured active galactic nuclei triggered in compact star-forming galaxies, Monthly Notices of the Royal Astronomical Society: Letters (2017). DOI: 10.1093/mnrasl/slw247


News Article | February 15, 2017
Site: spaceref.com

Astronomers have discovered a cosmic one-two punch unlike any ever seen before. Two of the most powerful phenomena in the Universe, a supermassive black hole, and the collision of giant galaxy clusters, have combined to create a stupendous cosmic particle accelerator. By combining data from NASA's Chandra X-ray Observatory, the Giant Metrewave Radio Telescope (GMRT) in India, the NSF's Karl G. Jansky Very Large Array, and other telescopes, researchers have found out what happens when matter ejected by a giant black hole is swept up in the merger of two enormous galaxy clusters. "We have seen each of these spectacular phenomena separately in many places," said Reinout van Weeren of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led the study that appears in the inaugural issue of the journal Nature Astronomy. "This is the first time, however, that we seen them clearly linked together in the same system." This cosmic double whammy is found in a pair of colliding galaxy clusters called Abell 3411 and Abell 3412 located about two billion light years from Earth. The two clusters are both very massive, each weighing about a quadrillion -- or a million billion -- times the mass of the Sun. The comet-shaped appearance of the X-rays detected by Chandra is produced by hot gas from one cluster plowing through the hot gas of the other cluster. Optical data from the Keck Observatory and Japan's Subaru telescope, both on Mauna Kea, Hawaii, detected the galaxies in each cluster. First, at least one spinning, supermassive black hole in one of the galaxy clusters produced a rotating, tightly-wound magnetic funnel. The powerful electromagnetic fields associated with this structure have accelerated some of the inflowing gas away from the vicinity of the black hole in the form of an energetic, high-speed jet. Then, these accelerated particles in the jet were accelerated again when they encountered colossal shock waves -- cosmic versions of sonic booms generated by supersonic aircraft -- produced by the collision of the massive gas clouds associated with the galaxy clusters. "It's almost like launching a rocket into low-Earth orbit and then getting shot out of the Solar System by a second rocket blast," said co-author Felipe Andrade-Santos, also of the CfA. "These particles are among the most energetic particles observed in the Universe, thanks to the double injection of energy." This discovery solves a long-standing mystery in galaxy cluster research about the origin of beautiful swirls of radio emission stretching for millions of light years, detected in Abell 3411 and Abell 3412 with the GMRT. The team determined that as the shock waves travel across the cluster for hundreds of millions of years, the doubly accelerated particles produce giant swirls of radio emission. "This result shows that a remarkable combination of powerful events generate these particle acceleration factories, which are the largest and most powerful in the Universe," said co-author William Dawson of Lawrence Livermore National Lab in Livermore, Calif. "It is a bit poetic that it took a combination of the world's biggest observatories to understand this." These results were presented at the 229th meeting of the American Astronomical Society meeting in Grapevine, TX. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations. A labeled image, a podcast, and a video about the findings are available at: http://chandra.si.edu For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra Please follow SpaceRef on Twitter and Like us on Facebook.


News Article | February 15, 2017
Site: spaceref.com

Fast radio bursts (FRBs) are brief spurts of radio emission, lasting just one-thousandth of a second, whose origins are mysterious. Fewer than two dozen have been identified in the past decade using giant radio telescopes such as the 1,000-foot dish in Arecibo, Puerto Rico. Of those, only one has been pinpointed to originate from a galaxy about 3 billion light-years away. The other known FRBs seem to also come from distant galaxies, but there is no obvious reason that, every once in a while, an FRB wouldn't occur in our own Milky Way galaxy too. If it did, astronomers suggest that it would be "loud" enough that a global network of cell phones or small radio receivers could "hear" it. "The search for nearby fast radio bursts offers an opportunity for citizen scientists to help astronomers find and study one of the newest species in the galactic zoo," says theorist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA). Previous FRBs were detected at radio frequencies that match those used by cell phones, Wi-Fi, and similar devices. Consumers could potentially download a free smartphone app that would run in the background, monitoring appropriate frequencies and sending the data to a central processing facility. "An FRB in the Milky Way, essentially in our own back yard, would wash over the entire planet at once. If thousands of cell phones picked up a radio blip at nearly the same time, that would be a good sign that we've found a real event," explains lead author Dan Maoz of Tel Aviv University. Finding a Milky Way FRB might require some patience. Based on the few, more distant ones, that have been spotted so far, Maoz and Loeb estimate that a new one might pop off in the Milky Way once every 30 to 1,500 years. However, given that some FRBs are known to burst repeatedly, perhaps for decades or even centuries, there might be one alive in the Milky Way today. If so, success could become a yearly or even weekly event. A dedicated network of specialized detectors could be even more helpful in the search for a nearby FRB. For as little as $10 each, off-the-shelf devices that plug into the USB port of a laptop or desktop computer can be purchased. If thousands of such detectors were deployed around the world, especially in areas relatively free from Earthly radio interference, then finding a close FRB might just be a matter of time. This work has been accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available online. Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe. Please follow SpaceRef on Twitter and Like us on Facebook.


News Article | February 27, 2017
Site: phys.org

An image of the Taurus Molecular Cloud, about 450 light-years from Earth. Many carbon-chain molecules have been detected towards dark clouds like these, but astronomers have sought HC11N without success. They speculate that chains this large preferentially transform into carbon rings. Credit: ESO; Digitized Sky Survey; Davide De Martin The interstellar medium of the Milky Way contains 5-10% of the total mass of the galaxy (excluding its dark matter) and consists primarily of hydrogen gas. There are small but important contributions from other gases as well, including carbon-bearing molecules both simple, like carbon monoxide and carbon dioxide, and complex like ethene, benzene, propynal, methanol and other alcohols, and cyanides. There are even some very large molecules like polycyclic aromatic hydrocarbons and buckyballs with fifty or more carbon atoms. Some species like the cyanides have relative abundances similar to what is seen in comets in our solar system, suggesting that local carbon chemistry is not unique. Astronomers think complex interstellar molecules are probably produced on dust grains, although some molecules might be produced in the gas phase. About one percent by mass of the interstellar material, these tiny grains are composed predominantly of silicates and provide the gas molecules with surfaces on which to react with other molecules. Carbon chain molecules are particularly interesting because they are thought to be the starting point for a significant fraction of the known complex chemicals in the interstellar medium. It is even suspected that carbon-chain species are a key stage in the formation of polycyclic aromatic hydrocarbons. Carbon-chain molecular chemistry thus provides insight into a large subset of interstellar chemistry. A particularly well-studied family of carbon chains is the cyanopolyynes: linear molecules of the form HCnN, where n = 3, 5, 7, 9, etc. They have been observed in high abundance towards older stars and in cold dark clouds. The presence of the largest known cyanopolyyne, HC11N, however, is in dispute. It was reportedly detected in 1982 towards one dark cloud in Taurus, but that detection has not been confirmed. CfA astronomers Ryan Loomis and Brett McGuire and their colleagues used the Green Bank Telescope to search the Taurus region for HC11N in six of its characteristic radio wavelength transitions, including the two in which it was first reported, but without success. The astronomers argue that the previous detection was an error, and they offer an explanation for the otherwise curious absence of the n=11 species. Laboratory experiments have shown that when carbon-chain molecules get to be longer than about n=9 they begin to curl on themselves and preferentially transform into carbon-ring molecules, which are more stable. A similar process could be occurring in the interstellar medium, siphoning away HC11N to form cyclic species. The non-detection of HC11N thus suggests the importance of this chemical pathway in producing cyclic molecules, although the authors note that further observations and laboratory experiments are needed to confirm the model. Explore further: The formation of carbon-rich molecules in space More information: Ryan A. Loomis et al. Non-detection of HCN towards TMC-1: constraining the chemistry of large carbon-chain molecules, Monthly Notices of the Royal Astronomical Society (2016). DOI: 10.1093/mnras/stw2302


The search for fast radio burst could be bolstered by citizen scientists using their mobile phones. A team of researchers has said a global network of phones and small radio receivers could be used to detect these mystery signals emanating from an unknown source in space. In a report that has been accepted for publication in the Monthly Notices of the Royal Astronomical Society, scientists from the Harvard-Smithsonian Centre for Astrophysics (CfA) and Tel Aviv University say if such a network were in place, it could be used to detect a simultaneous radio blip. This blip would indicate a FRB has been recorded – coming from inside the Milky Way. FRBs are radio signals coming from unknown sources deep in space. Lasting just a few milliseconds, scientists have struggled to identify their origin – the few dozen that have been detected were identified from data after the event, meaning their origin could not be traced back. At present, only one FRB has been found to repeat. In total, scientists have recorded 16 bursts coming from FRB 121102 – meaning they could be tracked to a galaxy three billion light years away. But even though we now know the location, we still do not know what is causing these bursts. The search for more FRBs continues, with astronomers across the globe using huge radio telescopes to detect them. The team say this presents an opportunity to harness a global collective of citizen scientists to look out for FRBs from within our own galaxy. While other FRBs appear to be coming from deep space, there is no reason to think one could not emanate closer to home. "An FRB in the Milky Way, essentially in our own back yard, would wash over the entire planet at once. If thousands of cell phones picked up a radio blip at nearly the same time, that would be a good sign that we've found a real event," said lead author Dan Maoz of Tel Aviv University. How it would work: We propose to search for Galactic FRBs using a global array of low-cost radio receivers. Participating phones would continuously listen for and record candidate FRBs and would periodically upload information to a central data processing website, which correlates the incoming data from all participants, to identify the signature of a real, globe-encompassing, FRB from an astronomical distance. Triangulation of the GPS-based pulse arrival times reported from different locations will provide the FRB sky position, potentially to arc-second accuracy. Pulse arrival times from phones operating at diverse frequencies, or from an on-device de-dispersion search, will yield the dispersion measure (DM) which will indicate the FRB source distance within the Galaxy. FRBs have been detected at frequencies that match those used by mobile phones and Wi-Fi. Potentially, people could download an app that would constantly be running in the background, monitoring frequencies. It could then send data to a central processing facility where any abnormalities could be identified. The researchers calculate there might be FRBs in the Milky Way once every 30 to 1,500 years. But if it is a repeating burst – like FRB 121102 – it may pop up every week. "If FRBs originate from galaxies at cosmological distances, then their all-sky rate implies that the Milky Way may host an FRB on average once every 30 to 1,500 years," they wrote. "If FRBs repeat for decades or centuries, a local FRB could be active now." Avi Loeb, from the CfA, said: "The search for nearby fast radio bursts offers an opportunity for citizen scientists to help astronomers find and study one of the newest species in the galactic zoo."

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