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  • richardmitnick 4:02 pm on April 19, 2016 Permalink | Reply
    Tags: , IceCube Experiment, ,   

    From phys.org: “First high-energy neutrino traced to an origin outside of the Milky Way” 

    physdotorg
    phys.org

    1
    a, The Fermi/LAT γ-ray light curve is shown as two-week binned photon fluxes between 100 MeV and 300 GeV (black), the Bayesian blocks light curve (blue), and the HESE-35 time stamp (red line). The HESE period (May 2010 to May 2013) and the included outburst time range are highlighted in colour. Only statistical uncertainties are considered and shown at a 1 sigma confidence level.

    b, VLBI images show the core region at 8.4 GHz from 13 November 2011 (2011.87), 16 September 2012 (2012.71) and 14 March 2013 (2013.20) in uniform colour scale. 1 mas corresponds to about 8.3 pc. All contours start at 3.3 mJy beam−1 and increase logarithmically by factors of 2. The images were convolved with the enclosing beam from all three observations of 2.26 mas × 0.79 mas at a position angle of 9.5°, which is shown in the bottom left. The peak flux density increases from 1.95 Jy beam−1 (April 2011) to 5.62 Jy beam−1 (March 2013). Credit: Nature Physics (2016) doi:10.1038/nphys3715

    An international team of researchers has spotted the first instance of a high-energy neutrino collision from a source outside of the Milky Way, marking what they describe as a significant discovery. In their paper* published in the journal Nature Physics, the team describes their work at the South Pole Neutrino Observatory, the details pertaining to the sighting and why they believe their discovery may lead to a new era in neutrino astrophysics.

    U Wisconsin ICECUBE neutrino detector
    IceCube neutrino detector interior
    U Wisconsin ICECUBE neutrino detector

    Neutrino’s are massless and have no charge and very seldom interact with other matter—the exception is when they collide head on with another particle. Scientists have been studying neutrinos for several years, believing that they may hold the key to understanding many parts of the universe that remain otherwise hidden from our view. To see evidence of them, researchers fill large underground tanks with different types of fluids and then use extremely sensitive sensors to capture very brief flashes of light which are emitted when a neutrino collides with something in the fluid. The team with this latest effort has taken a different approach, they have placed sensors around a kilometer sized ice cube 2.5 kilometers beneath the surface, in a location near the South Pole. The sensors capture the brief flashes that occur when neutrinos collide with particles in the ice.

    Capturing evidence of collisions does not happen very often, but when it does, it sets off a chain of events that center around trying to ascertain where the neutrino came from—most come from the sun or cosmic rays striking our atmosphere. But back in 2012, the team captured evidence of what they described as the most powerful yet, registering two petavolts. Following that discovery, the team used data from radio telescopes, and in particular data from a galaxy that has been named KS B1424-418—astrophysicists have been studying it for several decades and it had been observed to undergo a change in shape during the time period 2011 to 2014. After much analysis, the team confirmed that the neutrino collision they observed was due to an emission from that very galaxy, making it the first neutrino collision to be traced back to a source outside of the Milky Way.

    Science paper:
    Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event

    See the full article here .

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    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 5:44 pm on April 6, 2016 Permalink | Reply
    Tags: , IceCube Experiment, , The sun sets for six months   

    From IceCube: “Week 12 at the Pole” 

    icecube
    IceCube South Pole Neutrino Observatory

    06 Apr 2016
    Jean DeMerit
    Images by Christian Krueger, IceCube/NSF

    1

    A mushroom cloud … at the South Pole? What’s going on down there? What’s going on is actually a rising full moon getting distorted by the atmosphere. Pretty cool image. The moon is reflecting a bright sun that officially set last week at the Pole, not to reappear for another six months. But what a gorgeous sunset it was. The image below shows a nice indoor view, where the sharp line of the horizon—bright orange sky contrasted with cold blue ground—extends through a row of windows in the galley.

    Activities? The station held their traditional sunset dinner, which had not only duck but also lobster on the menu. Nice. It was also time to remove the flags from the ceremonial South Pole for the winter. One minute they were there, the next they were gone (almost). Finally, some shenanigans were apparently in order, as shown by winterover Christian posing as if to cut the cables and say good-bye to IceCube as they had just said good-bye to the sun.

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    3

    4

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    See the full article here .

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    ICECUBE neutrino detector
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
  • richardmitnick 12:23 pm on February 18, 2016 Permalink | Reply
    Tags: , , , IceCube Experiment, ,   

    From Penn State: “New clues in the hunt for the sources of cosmic neutrinos” 

    Penn State Bloc

    Pennsylvania State University

    cosmic-ray accelerator hidden
    This illustration is an example of a hidden cosmic-ray accelerator. Cosmic rays are accelerated up to extremely high energies in dense environments close to black holes. High-energy gamma rays (marked by the “Y” gamma symbol) are blocked from escaping, while neutrinos (marked by the “V”nu symbol) easily escape and can reach the Earth. Credit: Bill Saxton at NRAO/AUI/NSF, modified by Kohta Murase at Penn State University

    The sources of the high-energy cosmic neutrinos that are detected by the IceCube Neutrino Observatory buried in the Antarctic ice may be hidden from observations of high-energy gamma rays, new research reveals.

    ICECUBE neutrino detector
    IceCube neutrino detector interior
    U Wisconsin/NSF/ICECUBE

    These high-energy cosmic neutrinos, which are likely to come from beyond our Milky Way Galaxy, may originate in incredibly dense and powerful objects in space that prevent the escape of the high-energy gamma rays that accompany the production of neutrinos. A paper describing the research will be published in the early online edition of the journal Physical Review Letters on February 18, 2016.

    “Neutrinos are one of the fundamental particles that make up our universe,” said Kohta Murase, assistant professor of physics and of astronomy and astrophysics at Penn State and the corresponding author of the studies. “High-energy neutrinos are produced along with gamma rays by extremely high-energy radiation known as cosmic rays in objects like star-forming galaxies, galaxy clusters, supermassive black holes, or gamma-ray bursts [GRB’s]. It is important to reveal the origin of these high-energy cosmic neutrinos in order to better understand the underlying physical mechanisms that produce neutrinos and other extremely high-energy astroparticles and to enable the use of neutrinos as new probes of particle physics in the universe.”

    Neutrinos are neutral particles, so they are not affected by electromagnetic forces as they travel through space. Neutrinos detected here on Earth therefore trace a direct path back to their distant astrophysical sources. Additionally, these neutrinos rarely interact with other kinds of matter — many pass directly through the Earth without interacting with other particles — making them incredibly difficult to detect, but ensuring that they escape the incredibly dense environments in which they are produced.

    The high-energy cosmic neutrinos detected by IceCube are believed to originate from cosmic-ray interactions with matter (proton-proton interactions); from cosmic-ray interactions with radiation (proton-photon interactions); or from the decay or destruction of heavy, invisible dark matter. Because these processes generate both high-energy neutrinos and high-energy gamma rays, the scientists compared the IceCube neutrino data to high-energy gamma rays detected by the Fermi Gamma-ray Space Telescope.

    NASA Fermi Telescope
    Fermi Gamma-ray Space Telescope

    “If all of the high-energy gamma rays are allowed to escape from the sources of neutrinos, we had expected to find corresponding data from IceCube and Fermi,” said Murase. In previous papers, including one that was featured as an Editorial Suggestion in Physical Review Letters in 2015, Murase and his colleagues showed the power of such a “multi-messenger” comparison. Now, the researchers suggest that the new neutrino data collected by IceCube has lead to intriguing contradictions with the gamma-ray data collected by Fermi.

    “Using sophisticated calculations and a detailed comparison of the IceCube data with the gamma-ray data from Fermi has led to new and interesting implications for the sources of high-energy cosmic neutrinos,” said Murase. “Surprisingly, with the latest IceCube data, we don’t see matching high-energy gamma-ray data detected by Fermi, which suggests a ‘hidden accelerator’ origin of high-energy cosmic neutrinos that Fermi has not detected.”

    In order to explain the multi-messenger data without any of the intriguing contradictions, the scientists propose that the high-energy gamma rays must be blocked from escaping the sources that created them. The researchers then asked what kinds of astrophysical events could produce high-energy neutrinos but also could suppress the high-energy gamma rays detectable by Fermi. “Interestingly, we found that the suppression of high-energy gamma rays should naturally occur when neutrinos are produced via proton-photon interactions,” said Murase. The low-energy photons that interact with protons to produce neutrinos in these events simultaneously prevent high-energy gamma rays from escaping via a process called ‘two-photon annihilation.’ The new finding implies that the amount of high-energy gamma rays associated with the neutrinos that reach the Earth can easily be below the level detectable by Fermi.

    According to the researchers, the results imply that high-energy cosmic neutrinos can be used as special probes of dense astrophysical environments that cannot be seen in high-energy gamma rays. Candidate sources include supermassive black holes and certain types of gamma-ray bursts. The results also motivate further theoretical and observational studies, such as the use of lower-energy gamma rays or X rays to help scientists understand the origin of high-energy neutrinos and cosmic rays.

    “The next decade will be a golden era for multi-messenger particle astrophysics with high-energy neutrinos detected in IceCube as well as gravitational waves detected with advanced-LIGO,” said Murase.

    Caltech Ligo
    MIT/Caltech Advanced aLIGO

    “Our work demonstrates that multi-messenger approaches are indeed very powerful tools for probing fundamental questions in particle astrophysics. I believe that the future is bright and that we will be able to find sources of neutrinos and cosmic rays, probably with other surprising new discoveries.”

    In addition to Murase, the research team includes Dafne Guetta from the Osservatorio Astronomic di Roma in Italy and ORT Braude College in Israel, and Markus Ahlers from the University of Wisconsin.

    The research was funded by Penn State University, the U.S. Nation Science Foundation (grant numbers OPP-0236449 and PHY-0236449) and by the U.S. Israel Binational Science Foundation.

    See the full article here.

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  • richardmitnick 3:28 pm on December 1, 2015 Permalink | Reply
    Tags: , IceCube Experiment,   

    From IceCube: “A search for cosmic-ray sources with IceCube, the Pierre Auger Observatory, and the Telescope Array” 

    icecube
    IceCube South Pole Neutrino Observatory

    01 Dec 2015
    Sílvia Bravo

    High-energy neutrinos are thought to be excellent cosmic messengers when exploring the extreme universe: they don’t bend in magnetic fields as cosmic rays (CRs) do and they are not absorbed by the radiation background as gamma rays are. However, it turns out that the deviation of some CRs, namely protons, is expected to be only a few degrees at energies above 50 EeV. This opens the possibility for investigating common origins of high-energy neutrinos and CRs.

    In a new study by the IceCube, Pierre Auger, and Telescope Array Collaborations, scientists have looked for correlations between the highest energy neutrino candidates in IceCube and the highest energy CRs in these two cosmic-ray observatories.

    Pierre Augur Observatory
    Pierre Auger

    Telescope Array Collaboration
    Telescope Array Collaboration

    The results, submitted today to the Journal of Cosmology and Astroparticle Physics, have not found any correlation at discovery level. However, potentially interesting results have been found and will continue to be studied in future joint analyses.

    2
    Maps in Equatorial and Galactic coordinates showing the arrival directions of the IceCube cascades (black dots) and tracks (diamonds), as well as those of the UHECRs detected by the Pierre Auger Observatory (magenta stars) and Telescope Array (orange stars). The circles around the showers indicate angular errors. The black diamonds are the HESE tracks while the blue diamonds stand for the tracks from the through-going muon sample. The blue curve indicates the Super-Galactic plane. Image: IceCube, Pierre Auger and Telescope Array Collaborations.

    The IceCube astrophysical neutrino flux is consistent with an isotropic distribution, which suggests that most neutrinos have an extragalactic origin. The intensity of this flux is also found to be close to the so-called Waxman-Bahcall flux, which is the rate assuming that ultra-high-energy CRs (UHECRs) are mainly protons and have a power-law spectrum. In this scenario, primary cosmic rays collide to a significant extent with photons and neutrons within the source environment, resulting in mainly protons escaping from these sources.

    The UHECRs detected by the Pierre Auger Observatory (Auger) and the Telescope Array (TA) that were used in this study have energies above 50 EeV, since at the highest energies cosmic rays are deflected the least. UHECRs produce neutrinos that carry only 3-5% of the original proton energy, i.e., neutrinos that would have energies of at least several hundred PeVs for the CR sample of this work. However, we expect that the sources of these UHECRs will also produce lower energy CRs, which would then produce neutrinos in the energy range—30 TeV to 2 PeV—observed in IceCube. And this is the idea behind this search: to look for a statistical excess of neutrinos in IceCube from the direction of cosmic rays in the Auger and TA and, thus, their sources.

    Not a simple search, but definitely worth trying to study since searches for the most obvious potential CR sources using IceCube neutrinos have not been successful so far. The major challenges of this search are: i) CRs do not precisely point to their sources, and our knowledge of the deviations produced by the galactic magnetic fields is limited; ii) cascade neutrino events—mainly produced by electron and tau neutrinos—in IceCube are characterized by large angular uncertainties; and iii) IceCube neutrino candidates include background muon events due to the interaction of CRs with the Earth’s atmosphere.

    Researchers have used three different analyses to tackle these challenges. They first searched for cross-correlations between the number of CR-neutrino pairs at different angular windows and compared them to expectations for the null hypothesis of an isotropic UHECR flux. Then, they used a stacking likelihood analysis that looked for the combined contribution from different sources. These two searches used both cascade and track neutrino events from the astrophysical neutrino fluxes measured in IceCube (HESE and high-energy throughgoing muons). IceCube track neutrino signatures are produced by charged-current interactions of muon neutrinos and have an angular uncertainty of less than one degree. Finally, they performed a third study, a stacking search using the neutrino sample used for the four-year point-source search in IceCube, which includes track neutrino candidates only.

    The results obtained are all below 3.3 sigma. There is a potentially interesting finding in the analyses performed with the set of high-energy cascades. When compared to an isotropic flux of neutrinos (fixing the positions of the cosmic rays) to consider the effect of anisotropies in the arrival directions of cosmic rays, the significance is 2.4 sigma for the cross-correlation analysis. These results were obtained with relatively few events and the collaborations will update the analyses in the future with additional statistics to follow their evolution.

    + Info: Search for correlations between the arrival directions of IceCube neutrino events and ultrahigh-energy cosmic rays detected by the Pierre Auger Observatory and the Telescope Array, IceCube, Pierre Auger and Telescope Array Collaborations: M.G.Aartsen et al. Submitted to Journal of Cosmology and Astroparticle Physics, arxiv.org/abs/1511.09408

    See the full article here .

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    ICECUBE neutrino detector
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
  • richardmitnick 5:25 pm on August 20, 2015 Permalink | Reply
    Tags: , IceCube Experiment,   

    From IceCube: “IceCube confirms the astrophysical nature of high-energy neutrinos with an independent search in the Northern Hemisphere” 

    icecube
    IceCube South Pole Neutrino Observatory

    20 Aug 2015
    IceCube Collaboration

    Francis Halzen, PI IceCube
    University of Wisconsin-Madison
    francis.halzen@icecube.wisc.edu

    Olga Botner
    Professor of Physics
    University of Uppsala
    olga.botner@physics.uu.se

    Today, the IceCube Collaboration announces a new observation of high-energy neutrinos that originated beyond our solar system. This study, which looked for neutrinos coming from the Northern Hemisphere, confirms their cosmic origin as well as the presence of extragalactic neutrinos and the intensity of the neutrino rate. The first evidence for astrophysical neutrinos was announced by the collaboration in November 2013. The results published now in Physical Review Letters are the first independent confirmation of this discovery.

    “Looking for muon neutrinos reaching the detector through the Earth is the way IceCube was supposed to do neutrino astronomy, and with this paper, it delivered,” says Francis Halzen, principal investigator of IceCube and the Hilldale and Gregory Breit Distinguished Professor of Physics at the University of Wisconsin–Madison. “It is not quite CMS and ATLAS, but this is as close to an independent confirmation as one can get with a single instrument.”

    1
    This image shows one of the highest-energy neutrino events of this study superimposed on a view of the IceCube Lab (ICL) at the South Pole. Image: IceCube Collaboration

    Neutrinos are subatomic particles that travel throughout the universe almost undisturbed by matter, pointing directly to the sources where they were created. And for the highest energy neutrinos, those sources are expected to be the most extreme environments in the universe: powerful cosmic generators, such as black holes or massive exploding stars, that are able to accelerate cosmic rays to energies over a million times the energies achieved by record-breaking human-made accelerators, such as the LHC at CERN.

    “Cosmic neutrinos are the key to yet unexplored parts of our universe and might be able to finally reveal the origins of the highest energy cosmic rays, including the rare ‘Oh-My-God’ particles,” says collaboration spokesperson Olga Botner, of Uppsala University. “The discovery of astrophysical neutrinos hints at the dawn of a new era in astronomy.”

    Neutrinos are never directly observed, but IceCube is able to see the by-products of a neutrino interaction with the Antarctic ice. This cubic-kilometer detector records a hundred thousand neutrinos every year, most of them produced by the interaction of cosmic rays with the Earth’s atmosphere. Billions of atmospheric muons created in the same interactions also leave traces in IceCube. And from all of these, researchers are looking for only a few dozen astrophysical neutrinos, which will expand our current understanding of the universe.

    The search presented today by the IceCube Collaboration uses an old strategy for a neutrino telescope: it looks at the universe through the Earth, using our planet to filter the large background of atmospheric muons. More than 35,000 neutrinos were found in data recorded between May 2010 and May 2012. At the highest energy, above 100 TeV, the measured rate cannot be explained by neutrinos produced in the Earth’s atmosphere, indicating the astrophysical nature of high-energy neutrinos. The analysis presented in this paper suggests that more than half of the 21 neutrinos above 100 TeV are of cosmic origin.

    This independent observation, with a significance of 3.7 sigma and in good agreement with previous results by the IceCube Collaboration, also confirms the high rate of astrophysical neutrinos. Even though scientists are still counting them by the handful, IceCube results are close to the maximum rates based on potential cosmic ray sources. The intensity of this flux shows that cosmic ray sources are also efficient generators of neutrinos. And, therefore, these tiny particles are further endorsed as the perfect tools to explore the extreme universe.

    3
    Sky map in equatorial coordinates of the arrival direction of the 21 highest-energy events of this analysis (red dotted circles). The most probable neutrino energy (in TeV) indicated for each event assumes the best-fit astrophysical flux of the analysis. For comparison, the events of the 3-year high-energy starting event (HESE) analysis with deposited energy larger than 60 TeV (tracks and cascades) are also shown. Cascade events are indicated together with their median angular uncertainty (thin circles). Image: IceCube Collaboration

    The observed high-energy neutrinos are a brand-new neutrino sample, with only one event in common with the first results announced in 2013, which searched for high-energy neutrinos that had interacted with the ice inside IceCube during the same data-taking period. The current search looked for muon neutrinos only. These neutrinos produce a muon when they interact with the ice and have a characteristic signature in IceCube, called a track, that makes them easy to identify. The same shape is expected for an atmospheric muon, but by looking only at the Northern Hemisphere, researchers know that a detected muon could have only been produced by a neutrino interaction.

    These neutrino-induced tracks have a very good pointing resolution, in which they can locate their sources within less than a degree. However, IceCube’s studies have not yet found a significant number of neutrinos coming from any single source. The neutrino flux measured by IceCube in the Northern Hemisphere has the same intensity as the astrophysical flux in the Southern Hemisphere. This adds support to a large population of extragalactic sources, since otherwise sources in the Milky Way would dominate the flux around the galactic plane.

    In addition, this new high-energy neutrino sample, when combined with previous IceCube measurements, allows the most accurate measurements to date of the energy spectrum and neutrino-type composition of the extraterrestrial neutrino flux. Those results are published in an accompanying paper in The Astrophysical Journal.

    IceCube, run by the international IceCube Collaboration and headquartered at the Wisconsin IceCube Particle Astrophysics Center (WIPAC) at UW–Madison, is a gigaton particle detector located near the Amundsen-Scott South Pole Station, one of the scientific facilities in Antarctica managed by NSF. It is buried beneath the surface, extending to a depth of about 2,500 meters. A surface array, IceTop, and a denser inner subdetector, DeepCore, significantly enhance the capabilities of the observatory, making it a multipurpose facility.

    The IceCube Neutrino Observatory was built under an NSF Major Research Equipment and Facilities Construction grant, with assistance from partner funding agencies around the world. The NSF’s Division of Polar Programs and Physics Division continue to support the project with a Maintenance and Operations grant, along with international support from participating institutions and their funding agencies. UW–Madison is the lead institution, and the international collaboration includes 300 physicists and engineers from the U.S., Germany, Sweden, Belgium, Switzerland, Japan, Canada, New Zealand, Australia, U.K., Korea and Denmark.

    + info Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube, IceCube Collaboration: M.G. Aartsen et al. Physical Review Letters 115, 081102 (2015).

    See the full article here.

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    ICECUBE neutrino detector
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
  • richardmitnick 7:47 pm on August 4, 2015 Permalink | Reply
    Tags: , IceCube Experiment, ,   

    From Symmetry: “IceCube sees highest-energy neutrino ever found” 

    Symmetry

    August 04, 2015
    Kathryn Jepsen

    Observations of this kind could lead scientists to the source of ultra-high-energy cosmic rays.

    https://i0.wp.com/www.symmetrymagazine.org/sites/default/files/styles/lead_image/public/images/standard/IceCube_Aurora.jpg
    Photo by Ian Rees, IceCube/NSF

    In 2013, the IceCube neutrino experiment at the South Pole reported the observation of two ultra-high-energy neutrino events, which they named after Sesame Street characters Bert and Ernie. Later, they found one more.

    It seems a fourth character has moved into the neighborhood. Today IceCube scientists reported the observation of an even higher-energy neutrino event, one that offers scientists the best hope yet that they will be able to use ultra-high-energy neutrinos to find the source of ultra-high-energy cosmic rays. The neutrino event had an energy of more than 2000 trillion electronvolts.

    “We have been adding to our previous analysis more years of data, and in an extra year we found this spectacular event,” says Francis Halzen, IceCube principle investigator for the University of Wisconsin, Madison.

    For more than a century, scientists have known that particles called cosmic rays rain down on the Earth from space. Some of these cosmic rays slam into our atmosphere at energies higher than we could possibly reach in any earthly particle accelerator. It is still a mystery where these particles come from, but it seems that they are from energetic sources outside our galaxy. One suspicion is that they are coming from active galaxies swirling around distant black holes.

    Cosmic rays are charged particles, which means that their paths bend and shift as they pass through magnetic fields in space. That makes it difficult to trace their origins.

    That’s where neutrinos come in. Neutrinos are neutral, rarely interacting particles that can pass through entire planets without changing course. Ultra-high-energy neutrinos that the IceCube experiment observes could be coming from the same sources as ultra-high-energy cosmic rays. If so, they could point the way back to those sources.

    “This opens the neutrino astronomy field,” says Fermilab neutrino scientist Anne Schukraft, a former member of the IceCube collaboration.

    Neutrinos come in three types, called flavors: electron, muon and tau. When electron and tau neutrinos interact with the ice around the IceCube neutrino detector, their energy appears to balloon out from their interaction points, making it difficult to figure out exactly where they came from.

    This latest ultra-high-energy neutrino, however, was a muon neutrino. When muon neutrinos interact, they release a muon, a heavy cousin of the electron that can travel straight through matter for several kilometers before running out of steam.

    In this case, a neutrino passed through the Earth and interacted somewhere outside of the IceCube detector. The muon it released passed through it, drawing a distinct line to show where it came from.

    From there, “Standard Model physics can run the movie backwards,” Halzen says.

    1
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    The muon they detected had an energy of more than 2000 trillion electronvolts; the neutrino that produced it likely had about three times that energy. The only known source of such a high-energy muon coming through the Earth is a muon neutrino.

    The detector originally picked up the event on June 11, 2014. The IceCube collaboration conducts a blind analysis of its data, which means that it looks at it in large batches, in this case collected over a couple of years.

    When they looked at their data, they sent an alert to scientists working on the HAWC Gamma-Ray Observatory, an array that collects gamma-ray data from a large range of the sky over time.

    HAWC High Altitude Cherenkov Experiment
    HAWC High Altitude Cherenkov Experiment

    Scientists have already looked through HAWC 2014 data for an associated gamma-ray signal, says gamma-ray scientist Werner Hofmann of the Max Planck Institute for Nuclear Physics in Germany.

    From here on out, Halzen says, the IceCube collaboration will send alerts to other experiments that study gamma rays as soon as possible after detecting an ultra-high-energy neutrino event.

    “We are now going to announce events in real time,” Halzen says. “We’re going to bring out events like this hopefully in minutes.”

    That way even telescopes like the VERITAS telescope or the Fermi Gamma-ray Space Telescope will be able to point in the right direction to try to find a signal. Halzen says he expects these “astronomical telegrams” to come about once per month.

    Additional reporting contributed by Ali Sundermier.

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 9:24 am on July 16, 2015 Permalink | Reply
    Tags: , , IceCube Experiment,   

    From IceCube: “A combined analysis of the astrophysical neutrino flux in IceCube” 

    icecube
    IceCube South Pole Neutrino Observatory

    16 Jul 2015
    Sílvia Bravo

    Since the first detection of neutrinos with PeV energies, IceCube researchers have performed several follow-up studies to investigate the nature of the astrophysical neutrino flux. These analyses have revealed, for instance, that this flux extends down to energies around 25 TeV and that it displays different event topologies.

    The IceCube Collaboration is now revisiting these results in a combined analysis accepted for publication in The Astrophysical Journal. The analysis is based on the results of six individual studies and uses up to three observables—energy, zenith angle and event topology—to derive improved constraints on the energy spectrum and the composition of neutrino flavors (νe , νμ , ντ) of the astrophysical neutrino flux.

    The current study shows that the energy spectrum of the astrophysical neutrino flux is well described by a power law with a best-fit spectral index of -2.50 ± 0.09, for energies between 25 TeV and 2.8 PeV. A continuous power-law spectrum with index -2, which is a popular benchmark model, is excluded with a significance of 3.8 sigma.

    1
    Energy spectrum of the astrophysical neutrino flux derived in the combined analysis (red shaded area). The blue shaded area shows the flux of neutrinos created in the decay of pions and kaons in the atmosphere; the green line is an upper limit on the flux of so-called prompt atmospheric neutrinos from the decay of charmed mesons. Image: IceCube Collaboration.

    The combined analysis benefits from an increased size of the event sample, which is also more diverse—including track-like as well as shower-like events. Tracks are produced by most interactions of muon neutrinos, in which long-range muons are produced. On the other hand, interactions of electron and tau neutrinos, as well as some muon neutrinos, give rise to shower-like events.

    “With this study, we are able to present the first comprehensive characterization of the astrophysical neutrino flux at IceCube,” explains Lars Mohrmann, an IceCube researcher at DESY in Zeuthen and corresponding author of the paper.

    The flavor composition of the astrophysical neutrino flux brings us information about the production mechanism and the properties of the neutrino sources. In many scenarios, neutrinos are produced in the decay of pions, which create one electron neutrino per every two muon neutrinos and no tau neutrinos (νe : νμ : ντ =1:2:0). Because neutrinos switch flavors during their long journey through the universe, the 3-flavor composition at Earth is expected to be approximately even (≈1:1:1). The constraints on the flavor composition derived with this study show that the data are compatible with this scenario as well as with the sole production of muon neutrinos (0:1:0).

    In another mechanism, astrophysical neutrinos are produced in the decay of neutrons whereby only electron neutrinos are produced (1:0:0). However, this scenario is excluded with a significance of 3.6 sigma.

    2
    Constraints on the flavor composition of the astrophysical neutrino flux. Each of the three axes displays the fraction of a particular neutrino flavor with respect to the total flux. The best-fit composition is marked with X. Image: IceCube Collaboration.

    These results illustrate that we can learn something about the sources of the astrophysical neutrinos, even though we have not identified them yet,” continues Mohrmann. “It will be important to continue investigating the energy spectrum and the flavor composition with more data in the future.”

    + Info: “A combined maximum-likelihood analysis of the high-energy astrophysical neutrino flux measured with IceCube,” IceCube Collaboration: M. G. Aartsen et al. Accepted by The Astrophysical Journal, arxiv.org/abs/1507.03991

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ICECUBE neutrino detector
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
  • richardmitnick 3:35 pm on March 25, 2015 Permalink | Reply
    Tags: , , IceCube Experiment,   

    From DESY: “Latest result from neutrino observatory IceCube opens up new possibilities for particle physics” 

    DESY
    DESY

    2015/03/24
    No Writer Credit

    South Pole detector measures neutrino oscillations with high precision

    The South Pole observatory IceCube has recorded evidence that elusive elementary particles called neutrinos changing their identity as they travel through the Earth and its atmosphere.

    1
    The IceCube laboratory at the Scott Amundsen South Pole station hosts the computers collecting the detector data (picture: Felipe Pedreros. IceCube/NSF)

    IceCube neutrino detector interior
    IceCube Neutrino Experiment interior

    The observation of these neutrino oscillations, first announced in 1998 by the Super Kamiokande experiment in Japan, opens up new possibilities for particle physics with the Antarctic telescope that was originally designed to detect neutrinos from faraway sources in the cosmos.

    Super-Kamiokande experiment Japan
    Super Kamiokande experiment

    “We are very pleased that the IceCube detector with its DeepCore array can be used to observe neutrino oscillations with high precision,” says Olga Botner, Spokesperson of the IceCube experiment. “DeepCore was designed on the initiative of Per Olof Hulth who sadly passed away recently, to significantly lower IceCube’s energy threshold. The results show that IceCube can contribute to nailing down the oscillation parameters and motivate us to pursue our plans for an IceCube upgrade called PINGU to measure neutrino properties.”

    IceCube DeepCore
    IceCube DeepCore

    IceCube PINGU
    IceCube PINGU

    “IceCube records over one hundred thousand atmospheric neutrinos every year, most of them muon neutrinos produced by the interaction of fast cosmic particles with the atmosphere,” says Rolf Nahnhauer, leading scientist at DESY. The subdetector DeepCore allows for detecting neutrinos with energies down to 10 giga-electronvolts (GeV). “According to our understanding of neutrino oscillations, IceCube should see fewer muon neutrinos at energies around 25 GeV that reach IceCube after crossing the entire Earth,” explains Rolf Nahnhauer. “The reason for these missing muon neutrinos is that they oscillate into other types.” IceCube researchers selected Northern Hemisphere muon neutrino candidates with energies between a few GeV and around 50 GeV from data taken between May 2011 and April 2014. About 5200 events were found, much below the 7000 expected in the non-oscillations scenario.

    Neutrinos remain the most mysterious of the known elementary particles. Postulated by Austrian physicist Wolfgang Pauli in 1930, it took 25 years for their experimental detection. “Neutrinos are elusive,” says Olga Botner, ” and can travel through an enormous amount of material, even the whole Earth, without interacting.” Nevertheless, physicists have built more and more sophisticated instruments to reveal the mysteries of this very light particles. One of the surprising results was that the three different types of neutrinos, electron, muon and tau neutrinos, can change their identity, transforming from one type of neutrino to another. This phenomenon is known as neutrino oscillation. “Neutrino oscillations are only possible if neutrinos have a mass,” explains Nahnhauer. “On the other hand, massive neutrinos are not explained within the otherwise so successful Standard Model of particle physics.”

    3
    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    The strength of the oscillation and the distances over which it develops depend on two parameters: the so-called mixing angle and the mass difference. The values of these parameters have been constrained by precise measurements of neutrinos from the sun, the atmosphere, nuclear reactors, and particle accelerators.

    The IceCube neutrino observatory at the South Pole has already demonstrated that it is a powerful tool to explore the universe by neutrinos, using the Antarctic ice sheet as its detection material. An array of more than 5000 optical sensors distributed in a cubic kilometer of the ice records the very rare collisions of neutrinos. And less than two years ago, IceCube physicists announced the discovery of the first high-energy neutrinos from the cosmos, acknowledged as “breakthrough of the year” by the journal Physics World.

    Now IceCube has proven that it can also deliver top particle physics results. The new measurement by the IceCube collaboration resulting in significantly improved constraints on the neutrino oscillation parameters has been accepted for publication by the scientific journal Physical Review D.

    Three years of IceCube data yielded a similar precision to that reached from about 15 years of Super-Kamiokande data. In contrast to the purified water in Super-Kamiokande’s 50-kiloton vessel, IceCube uses a natural target material, the glacier ice at the South Pole. IceCube’s 500 times larger observation volume produces larger event statistics in shorter times. “Both Super-Kamiokande and IceCube use the same ‘beam‘ which is atmospheric neutrinos, but at different energies. And we reach similar precision of the measurable oscillation parameters,” says Juan Pablo Yanez, postdoctoral researcher at DESY, who is the corresponding author of the paper. “The results now derived from IceCube data show errors still larger than, but already comparable to the most precise neutrino beam experiments MINOS and T2K. But as IceCube keeps taking data and improving the analyses we are hopeful to catch up soon.” adds Yanez.

    Currently the scientists are planning an upgrade of the IceCube detector called PINGU (Precision IceCube Next Generation Upgrade). A much higher density of optical modules in the whole central region will improve the sensitivity to several fundamental questions associated with neutrinos.

    “In particular we want to measure the so called neutrino mass hierarchy – whether there are two heavier neutrinos and one light one, or whether it is the other way around.” explains Rolf Nahnhauer. “This is important to understand how neutrinos obtain masses, but also has significant relevance on how the cosmos evolves. The current results provide an important experimental confirmation that our concepts work.“

    See the full article here.

    Please help promote STEM in your local schools.

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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 3:28 pm on December 22, 2014 Permalink | Reply
    Tags: , , , , IceCube Experiment, ,   

    From IceCube: “Gamma-ray bursts are not main contributors to the astrophysical neutrino flux in IceCube” 

    icecube
    IceCube South Pole Neutrino Observatory

    22 Dec 2014
    Silvia Bravo

    Gamma-ray bursts (GRBs) were once the most promising candidate source of ultra-high-energy cosmic rays (UHECRs). They release extremely large amounts of energy in short periods of time, so if they could accelerate protons as they do electrons, then GRBs could account for most of the observed UHECRs.

    But along comes IceCube, the first gigaton neutrino detector ever built, ready to dig into the origin of UHECRs using neutrinos. There’s a whole universe in which to look for a signal but, to test GRBs as possible sources, they started with a search for neutrinos in coincidence with observed GBRs. Previous results, published by the IceCube Collaboration in 2012 in Nature, found no such coincidence. This cast doubt on GRBs as the main source of UHECRs. In a follow-up study submitted today to the Astrophysical Journal Letters, the collaboration shows that the contribution of GRBs to the observed astrophysical neutrino flux cannot be larger than about 1%.

    The study also sets the most stringent limits yet on GRB neutrino production, excluding much of the parameter space for the most popular models. The collaboration is now also providing a tool to set limits on other GRB models using IceCube data.

    grb
    The jet from a gamma-ray burst emerging at nearly light speed. Image credit: NASA / Swift / Cruz deWilde.

    NASA SWIFT Telescope
    NASA/Swift

    One may wonder how observing neutrinos in Antarctic ice tells us anything about cosmic rays and GRBs. The answer is simple, if you ask a physicist: neutrinos are an unambiguous signature of proton acceleration. And cosmic rays are, in their vast majority, very high energy protons.

    That cosmic rays exist at energies up to 10^20 eV is a fact; we have observed them with all sort of detectors since their discovery by Victor [Francis] Hess back in 1912. Physicists have developed several models that could explain how and where cosmic rays can be accelerated to such extreme energies. All of these models also tell us that any cosmic proton accelerator that we can imagine would also be a very high energy neutrino generator. While cosmic rays are scrambled by intergalactic magnetic fields, neutrinos travel in straight paths, potentially allowing us to identify their sources. For this reason, the search for the sources of cosmic rays has also become the search for very high energy neutrinos.

    IceCube, the first detector to measure a very high energy neutrino flux, is now squeezing every bit of information out of its data, to learn more about the origins of those neutrinos and thus of cosmic rays. In the current research, IceCube has looked for a neutrino signature in coincidence with over 500 GRBs observed during the data-taking period from April 2008 to May 2012. A single low-significance neutrino was found, confirming previous results by the collaboration. However, this data sample was much larger, including the first data from the completed detector and allowing still more stringent limits on GRB neutrino production.

    GRBs were once very promising candidates for the source of UHECRs. Corresponding author Michael Richman from University of Maryland notes that “using data taken from one year of operation of the completed detector, IceCube has already cast doubt on that hypothesis.” IceCube’s recent observation of an astrophysical neutrino flux marks a new era of neutrino astronomy. This flux is compatible with the expectation from cosmic ray production. While GRBs are excluded as dominant sources of either UHECRs or the diffuse astrophysical neutrinos, ongoing analyses will shed new light on these mysterious signals.

    + Info Search for Prompt Neutrino Emission from Gamma-Ray Bursts with IceCube, IceCube Collaboration: M.G. Aartsen et al. Submitted to Astrophysical Journal Letters, arxiv.org/abs/1412.6510

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ICECUBE neutrino detector
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
  • richardmitnick 8:51 pm on December 17, 2014 Permalink | Reply
    Tags: , IceCube Experiment,   

    From IceCube: “Designing the future of the IceCube Neutrino Observatory” 

    icecube
    IceCube South Pole Neutrino Observatory

    17 Dec 2014
    Sílvia Bravo

    The IceCube Neutrino Observatory is a successful and large scientific facility located near the Amundsen-Scott South Pole station in Antarctica. This observatory hosts IceCube, a cubic-kilometer deep-ice particle detector that is, so far, the largest ever built – and on the surface, IceTop, an extended air shower array.

    Completed in 2010, IceCube has recently discovered astrophysical neutrinos, revealing their potential to explore our universe at energies at the PeV scale and above, where most of the universe is opaque to high-energy photons. But the big questions remain unsolved: where do these neutrinos come from? How does nature accelerate particles to such extreme energies?

    Prof. Olga Botner, IceCube spokesperson and a physics professor at the University of Uppsala, and Prof. Francis Halzen, IceCube principal investigator and a professor at the University of Wisconsin–Madison, tell us about the plans for an upgrade to the IceCube Neutrino Observatory. As an extension of the current detector, it can be built in a few years and within an affordable budget, thanks to expertise acquired with IceCube.

    a
    Artistic view of the Antarctic surface around the South Pole station, showing the position of the 86 strings of sensors in IceCube and the possible grid of the next-generation detector. Image: J.Yang/IceCube Collaboration

    Q: What has IceCube accomplished so far?

    Olga Botner (O): IceCube is the world’s foremost neutrino observatory, which, after just two years of running in its final configuration, discovered neutrinos from outer space that have energies a billion times larger than those of neutrinos produced by our Sun and a thousand times larger than any produced on Earth with man-made accelerators. The discovery of this high-energy neutrino flux is a turning point for neutrino astronomy: a dream of 50 years ago on the verge of becoming reality.

    Francis Halzen (F): The high level of the observed neutrino flux implies that a significant fraction of the energy in the non-thermal universe, powered by the gravitational energy of compact objects from neutron stars to supermassive black holes, is generated in hadronic accelerators. This tells us that we are approaching exciting times when high-energy neutrinos will reveal new sources or provide new insight on the energy generation in known sources.

    But IceCube has also been a successful detector with respect to its technical development. We developed highly successful designs for transforming natural ice into a particle detector. The optimized methods for deploying and commissioning large volume detectors in ice can be used for a next-generation detector; minimal modifications will target improvements focused on modernization, efficiency, and cost savings.

    O: This is a very important point. The detector was built within the expected time frame, within budget, and with a performance at least a factor of two better than anticipated.

    Going back to physics, I should also add that IceCube has yielded many interesting results beyond neutrino astronomy. We are studying cosmic rays, looking for signatures of the annihilations of dark matter particles into neutrinos, and investigating the properties of the neutrinos themselves. We have published competitive results in all these areas.

    Q: Why do we need a next-generation IceCube detector?

    F: We all agree on the observed spectrum of neutrinos, there’s no doubt about the discovery, but independent analyses of IceCube data have produced only on the order of 100 astrophysical neutrino events in several years. These modest numbers of cosmic neutrinos limit the ability of IceCube to be an efficient tool for neutrino astronomy over the next decade. A next-generation detector will provide an unprecedented view of the high-energy universe, taking neutrino astronomy to new levels of discovery. It is likely to resolve the question of the origin of the cosmic neutrinos recently discovered.

    O: That’s right! IceCube’s discovery of extraterrestrial neutrinos has shown us that even a cubic-kilometer detector is not enough. To fully exploit the potential for neutrino astronomy, a much larger observatory is needed. We are already working on its design. The new detector has been named IceCube-Gen2.

    Q: Is it feasible and cost-effective to build an even bigger detector at the Pole?

    O: It sure is. The good news is that the successful deployment and running of IceCube demonstrates that we have mastered the technologies to construct and operate a detector in the deep ice. The drilling systems and the optical modules for the next-generation detector will closely follow the designs that have been proven to work well—with certain modifications to improve the overall performance. This makes us confident that a next-generation detector is not only feasible but can be built in a cost-effective manner, just like IceCube.

    F: We didn’t know this before IceCube, but now we have measured the extremely long photon absorption lengths in ice. This will allow the spacing between strings of light sensors to exceed 250 m in a future IceCube extension; i.e., the instrumented volume can rapidly grow without increasing the costs much. In fact, we can build a ten-cubic-kilometer IceCube-Gen2 telescope by roughly doubling the instrumentation already deployed. Thus, a tenfold increase in astrophysical neutrino detection rates could be achieved with a cost comparable to the current IceCube detector.

    Q: And what about the time scale of this project? Will we need to wait a long time to see new results?

    O: We are aiming at an expanded array instrumenting a volume of 10 km3 for the detection of high-energy neutrinos—but also at improving the low-energy performance through deployment of a densely instrumented infill detector, PINGU, targeting neutrino mass hierarchy as its prime goal. We believe that this new IceCube-Gen2 observatory can be built within seven years of obtaining funding.

    Q: Sounds like a plan. Who is leading this next-generation IceCube?

    F: The present plan is to build IceCube following a management strategy that was successful in delivering IceCube on time and on budget. The collaboration is rapidly expanding, both in the US and in Europe and Canada. We expect that a larger fraction of the cost will be carried by significant contributions from our foreign collaborators.

    O: Exactly. The high-energy array and PINGU are both envisioned as parts of an IceCube-Gen2 observatory. A new collaboration, including IceCube members and additional institutions, is now being formed. This IceCube-Gen2 collaboration will work to develop proposals in the US and abroad to secure funding. We hope that IceCube-Gen2 will become a flagship scientific project for NSF as well as for funding agencies abroad.

    o
    This image shows a simulated high-energy event of about 60 PeV in the proposed IceCube Gen2 detector. Image: IceCube Collaboration

    Q: Can other current or in-design experiments do better than IceCube-Gen2?

    F: Well, we have strong competitors. Early efforts for cubic-kilometer neutrino detectors focused on deep-water-based detectors, including DUMAND, Lake Baikal, and ANTARES. So far, there is no cubic-kilometer neutrino detector in deep water, but these experiments have paved the way toward the proposed construction of KM3NeT in the Mediterranean Sea and GVD in Lake Baikal.

    O: These new projects, GVD in Lake Baikal and KM3NeT in the Mediterranean, are presently in the prototyping or early construction phase. They will eventually provide a complementary view of the sky to that of an Antarctic observatory.

    Q: Should we expect IceCube-Gen2 to be as successful as IceCube? That may be the desire, but are there objective reasons to think so?

    O: The main one is that we already have established the existence of a flux of high-energy neutrinos. What we now need are substantial number of events to further characterize this flux in terms of energy spectrum, a possible energy cut-off, flavor composition, and provenance. We just need a larger detector to do this in a reasonable time. The higher event rates in a larger array will also improve the chances of correlating our neutrino events with observations by the new generation of high-energy gamma-ray telescopes and gravitational wave detectors, together charting the non-thermal universe.

    F: The larger samples of high-energy neutrinos with improved angular resolution and energy measurement will give us a detailed understanding of the source distribution. This sample will reveal an unobstructed view of the universe at energies at PeV and above. Those are unexplored wavelengths where most of the universe is opaque to high-energy photons. As Olga was mentioning, the operation of IceCube-Gen2 in coincidence with other telescopes and detectors will present totally novel opportunities for multimessenger astronomy and multiwavelength follow-up campaigns to obtain a truly complete picture of astrophysical sources.

    + Info IceCube-Gen2: A Vision for the Future of Neutrino Astronomy in Antarctica, IceCube Collaboration: M.G. Aartsen et al. arxiv.org/abs/1412.5106

    This white paper presents early studies toward a next-generation IceCube detector with the aim of instrumenting a 10 km3 volume of clear glacial ice at the South Pole and delivering an order of magnitude increase in astrophysical neutrino samples of all flavors.

    Read also a short description of IceCube-Gen2 on the IceCube w

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ICECUBE neutrino detector
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
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