Since 2016, the IceCube Collaboration has used a fast-response analysis pipeline to perform follow-up neutrino searches on interesting detections in other messengers that might have neutrino counterparts. As of July 2020, the pipeline led to 58 analyses, none of which found significant neutrino signals but enabled researchers to constrain neutrino emission from some potential sources. The collaboration described their results in a paper recently submitted to The Astrophysical Journal.
IceCube News Topic: Research
The IceCube Collaboration searches for neutrino sources using a variety of analysis methods. In a paper submitted yesterday to The Astrophysical Journal, the collaboration describes a time-dependent all-sky scan using five years of IceCube data as well as a specific analysis of blazar 3C 279. The analyses did not reveal any new neutrino point sources.
In a paper submitted recently to JCAP, the IceCube Collaboration describes a search for sub-TeV neutrino emission from astrophysical “transient” sources. This is the first transient result from IceCube to use all neutrino flavors in the 1-100 GeV energy region. In the absence of any observed sources in three years of archival IceCube data, the researchers established new limits on the volumetric rate of transients.
The number of neutrinos that IceCube detects is dependent on many factors, including the “neutrino cross section”: how likely it is for neutrinos to interact with nuclei in the ice. In a paper submitted today to Physical Review D, the IceCube Collaboration reports a new cross section measurement obtained by using 7.5 years of IceCube data. This is the first such measurement to incorporate all three neutrino flavors.
In a paper submitted today to The Astrophysical Journal, the AMON team, together with the IceCube and HAWC collaborations, present the analysis approach that they developed and reveal the first results from their analysis, as applied to three years of archival data from 2015 to 2018. During those three years, they identified two coincident events that met their criteria for distribution as a public alert, but there were no particularly important astronomical sources seen near either position.
In a white paper recently submitted to the Journal of Physics G, the international IceCube-Gen2 Collaboration outlines the need for and design of a next-generation extension of IceCube. By adding new optical and radio instruments to the existing detector, IceCube-Gen2 will increase the annual rate of cosmic neutrino observations by an order of magnitude, and its sensitivity to point sources will increase to five times that of IceCube.
While we have seen neutrinos and electromagnetic radiation with a common origin, researchers have yet to detect neutrinos and gravitational waves coming from the same place. So the IceCube Collaboration recently performed an analysis to look for neutrino emission that correlates with gravitational waves detected by the LIGO and Virgo Collaborations during their first two observing runs, O1 and O2. Their results are described in a paper published today in The Astrophysical Journal Letters. No coincidence was found, but the researchers are already at work on further analyses.
The IceCube Collaboration recently performed an analysis to try to expand our understanding of the solar magnetic field by studying the time-dependent cosmic-ray Sun shadow. They also wanted to explore how the cosmic-ray Sun shadow changes at different energy regimes. The results, recently submitted to Physical Review D, show that more solar activity leads to a weaker Sun shadow. There were also indications that, in times of high solar activity, the shadow becomes stronger at higher energies—a hint at Sun-shadow energy dependence that will be explored more in future studies.
In two new papers, the IceCube Collaboration updates their eV-scale sterile neutrino search using an eight-year dataset and improved event selection. The analysis found no evidence of sterile neutrinos at this energy scale and was consistent with the no-sterile-neutrino hypothesis.
IceCube has found a way to detect cosmic rays of lower energies previously unreachable by IceTop. In a paper submitted to Physical Review D, “Cosmic Ray Spectrum from 250 TeV to 10 PeV using IceTop,” the IceCube Collaboration explains how they implemented a new two-station trigger as well as the machine-learning method developed to analyze these events
In a paper recently submitted to The Astrophysical Journal, the IceCube Collaboration outlines an analysis that searched for neutrino emission from 35 pulsar wind nebulae in 9.5 years of IceCube data. They did not find any significant correlation, so the researchers set upper limits on total neutrino emission from these objects.
Dark matter is one of the biggest mysteries in science today, and neutrinos might be able to help. IceCube and ANTARES Collaborations recently probed a known dark matter hotspot—the center of the Milky Way—by combining data from their respective neutrino telescopes. They did not find any unusual excesses of neutrinos, but they put stronger constraints on the dark matter annihilation cross section averaged over the dark matter velocity. The results of the analysis are outlined in a paper submitted recently to Physical Review D.
Fast radio bursts (FRBs) are some of the most enigmatic phenomena in the universe. These millisecond-long pulses of radio waves most likely originate outside of our galaxy, but we don’t know much more than that. The IceCube Collaboration recently looked for neutrino events that coincided with 28 nonrepeating FRBs and one repeating FRB. Searching for neutrinos emitted from the same part of the sky as FRBs could provide clues to help test models that suggest particle acceleration near the FRB source. Results from this search are outlined in a paper published today in The Astrophysical Journal.
In a paper recently submitted to Physical Review Letters, the IceCube Collaboration presents new results of an analysis to determine and characterize, with unprecedented precision and across the entire sky, the combined flux of astrophysical electron and tau neutrinos.
For South Pole experiments like the IceCube Neutrino Observatory, all instruments—whether in the ice or on the surface—must undergo feasibility studies to make sure they can operate in the harsh Antarctic conditions. Optical instruments, especially, are subject to icing and snow accumulation. Recently, the IceCube Collaboration proved the successful operation of a new instrument, an imaging air-Cherenkov telescope, at the Pole. They outline the details of the study in a paper published today in the Journal of Instrumentation.
Researchers in the IceCube Collaboration are always looking for ways to improve the understanding of the PMTs so they can get the highest-quality data from the DOMs. Most recently, they implemented a new method for more accurately characterizing individual PMT charge distributions, which was shown to improve PMT calibration and simulation. The method is described in a technical report submitted today to the Journal of Instrumentation.
The IceCube Collaboration recently performed the first-ever experimental search for solar atmospheric neutrinos. Such a detection would have important implications for understanding solar magnetic fields and how cosmic rays propagate in the inner solar system, and it could even provide additional background to solar dark matter searches. But after investigating seven years of IceCube data, IceCube researchers did not detect any solar atmospheric neutrinos and so set an upper limit on the flux. Their results are outlined in a paper that was recently submitted to the Journal of Cosmology and Astroparticle Physics.
The IceCube Collaboration recently conducted a combined IceCube-ANTARES search for neutrino point-like and extended sources in the southern sky. They didn’t find any significant evidence for cosmic neutrino sources, but the analysis shows the strong potential for combining data sets from both experiments. Their results were submitted to The Astrophysical Journal.
IceCube isn’t the only neutrino experiment in Antarctica. There is also the ANITA (the ANtarctic Impulsive Transient Antenna) experiment, which flies a balloon over the continent and points radio antennae toward the ground in search of extremely high-energy neutrinos.
The IceCube Collaboration recently followed up on events detected by ANITA and presented their results in a paper submitted today to The Astrophysical Journal. The collaboration found that these neutrinos could not have come from an intense point source. Other explanations for the anomalous signals—possibly involving exotic physics—need to be considered.
IceCube has not yet found neutrino sources within our galaxy, but there may be sources that are not too much farther out. To test this possibility, the IceCube Collaboration recently performed an analysis scouring the local universe for potential neutrino sources. They conducted two different searches that looked for correlations between neutrino emission and dense regions in a catalog of galaxies called the 2MASS Redshift Survey (2MRS). While they did not find significant sources, they were able to put constraints on neutrino emission from nearby galaxies, which they present in a paper recently submitted to the Journal of Cosmology and Astroparticle Physics.
Neutrino mass ordering is one of the foremost problems in neutrino physics today. But two new neutrino oscillation experiments are on the horizon—the IceCube Upgrade and JUNO. So the IceCube Collaboration and the JUNO Collaboration studied the combined performance of their respective experiments, which employ very distinct and complementary routes in order to resolve the neutrino mass ordering. In a paper submitted recently to Physical Review D, they show that a combined analysis could eliminate the wrong mass ordering in as few as three years from the start of data taking.
Cascade events are more difficult to reconstruct than tracks, which are usually used in searches for astrophysical neutrino sources, but cascades have their own advantages, including providing a better measurement of neutrino energy. In a paper published in The Astrophysical Journal, the IceCube Collaboration outlined recent results from a source search that used seven years of data from cascade events. While they did not find any statistically significant sources of neutrino emissions, this work is an improvement on the previous source search with cascades.
In a paper recently published in Physical Review D, the IceCube Collaboration reports on measurements of the all-particle cosmic ray energy spectrum and composition in the PeV to EeV energy range using three years of data from the IceCube Neutrino Observatory.
Dark matter is one of the biggest mysteries in modern astronomy and physics. In a paper recently submitted to the European Physical Journal C, scientists from IceCube and PICO determined new constraints on particle physics properties of dark matter. Though these are less stringent than previous constraints, they take into consideration the latest research on the distribution of dark matter in our galaxy.
After 10 years of searching for origins of astrophysical neutrinos, a new all-sky search provides the most sensitive probe of time-integrated neutrino emission of point-like sources. The IceCube Collaboration presents the results of this scan in a paper submitted today to Physical Review Letters.
The IceCube Collaboration performed a search for point-source populations using a technique called the non-Poissonian template fit (NPTF) and published their findings in a paper submitted to The Astrophysical Journal. This was the first time the NPTF was used on IceCube neutrino data, and while they did not find any neutrino point-source populations, they proved the technique’s viability.
The IceCube Neutrino Observatory is an array of over 5,000 optical sensors embedded in a cubic kilometer of ice at the South Pole. Optical impurities in the ice affect how light travels through the IceCube detector and thus how the neutrino interactions appear. In a technical paper submitted to the Journal of Cosmology and Astroparticle Physics, the IceCube Collaboration presents a new method to understand the optical properties of the ice, called the SnowStorm method.
While the IceCube Neutrino Observatory is mostly known for detecting neutrinos, it is also the experiment most sensitive to PeV-scale gamma rays in the Southern Hemisphere. In a recent paper by the IceCube Collaboration submitted to The Astrophysical Journal, they discuss the results of a recent search for PeV gamma rays. No evidence of PeV gamma rays were found, but they established the most stringent constraints on PeV gamma-ray emission to date.
In a new paper by the IceCube Collaboration, physicists use the inner and denser DeepCore detector within IceCube to try to answer this question. A weak preference is shown for NO, a result that is complementary to and in agreement with results from other experiments. This paper has been submitted to the European Physical Journal.
In a recent paper by the IceCube Collaboration, two new techniques have improved searches at energies from 100 TeV down to 100 GeV. When tested with a few years of IceCube data, these new selections improve the sensitivity and discovery potential, for the first time allowing the search for galactic point-like sources using track events created by muon neutrinos, which in many cases are indistinguishable from atmospheric muon tracks. These results have just been submitted to the journal Astroparticle Physics .
In a recent publication submitted to Astronomy and Astrophysics, the IceCube Collaboration and Pan-STARRS1 scientists have searched for counterpart transient optical emission associated with IceCube high-energy neutrino alerts. When following five alerts sent during 2016-17, researchers found one supernova worth studying, SN PS16cgx. However, a more detailed analysis showed that it is most likely a Type Ia supernova, i.e., the result of a white dwarf explosion, which is not expected to produce neutrinos.
In a new paper by the IceCube Collaboration in partnership with scientists from the Fermi-LAT collaboration and the ASAS-SN telescopes, researchers went back to eight years of archived IceCube.
The results of this long-term search of high-energy neutrino emission from blazars confirm that this type of active galaxy cannot account for the majority of the diffuse neutrino flux seen by IceCube and that the source of most of the high-energy neutrinos is still unknown. These results have recently been submitted to Astronomy and Astrophysics.
The IceCube Collaboration has just performed its first measurement of tau neutrino appearance in oscillations of atmospheric muon neutrinos, which excluded the absence of tau neutrino oscillations at a significance of 3.2σ, confirming previous observations by OPERA and Super-Kamiokande. These results have just been submitted to the journal Physical Review D.
In an attempt to better understand the anisotropy, the IceCube Neutrino Observatory and the HAWC gamma-ray observatory have united their efforts to study cosmic-ray arrival directions in both hemispheres at the same primary energy. The goal of this combined observation was to get a nearly full-sky coverage to study the propagation of cosmic rays with median energy of 10 TeV through our local interstellar medium as well as the interactions between interstellar and heliospheric magnetic fields. Results have just been accepted for publication in The Astrophysical Journal and include measurements on how the anisotropy modulations are distributed over different angular scales.
Neutrinos allow us to test our models at higher energies than do gamma rays. In a first-time effort to combine IceCube and ANTARES data to constrain galactic cosmic-ray models, scientists from both collaborations have set new limits on some of these models as well as a new limit for the galactic contribution to the IceCube neutrino flux. These results have been published this week in the journal Astrophysical Journal Letters.
In a new attempt to lay siege to the steady sources of neutrinos, the IceCube Collaboration has improved the search for sources in the Northern Hemisphere using muon neutrino data. The new search with eight years of IceCube data and an upgraded event selection and reconstruction resulted in enhanced sensitivity and the most stringent limits yet on emission from steady sources. These results have just been submitted to the journal European Physical Journal C .
The IceCube, LIGO, Virgo, and ANTARES collaborations have used data from the first observing period of Advanced LIGO and from the two neutrino detectors to search for coincident neutrino and gravitational wave emission from transient sources. Scientists did not find any significant coincidence. The results, recently submitted to The Astrophysical Journal, set a constraint on the density of these sources.
The IceCube Collaboration has measured the Sun’s cosmic-ray shadow for the first time, from data covering a period of five years. The results, submitted today to The Astrophysical Journal, show a clear but different shadow pattern every year. When looking at the yearly variation, scientists have found that the shadow pattern follows changes in the solar activity, which we know are correlated with the strength of the Sun’s magnetic field. Thus, this study opens a new line of research for the Antarctic neutrino observatory: the study of the Sun’s magnetic field using IceCube cosmic-ray data.
The IceCube Collaboration has, once more, looked for extremely high-energy neutrinos. And now, after analyzing nine years of IceCube data, scientists set the most stringent limits on the existence of cosmogenic neutrinos to date. As a result, the idea that ultra-high-energy cosmic rays are mostly protons is vanishing. These results were published in the journal Physical Review D last week.
The IceCube Collaboration has recently presented its first measurements of the neutrino inelasticity, which are also the first-ever at very high energies—from 1 TeV up to nearly 800 TeV. The inelasticity distribution was found to be in good agreement with Standard Model prediction and was later used to perform other measurements, such as charm production in neutrino interactions or flavor composition of astrophysical neutrinos.
In a new search for neutrino sources, the IceCube Collaboration and other collaborators have looked for short-lived transient sources, including gamma-ray bursts, core-collapse supernovae, or neutron star mergers. The search, which looked for two or more neutrinos detected within 100 seconds from the same location, included transients that might not emit gamma rays and might be pointing to uncharted objects in the universe. The results submitted this week to Physical Review Letters did not identify any individual source but did show that the number of bright short-lived transient neutrino sources must be small or they must be fairly faint.
A new measurement of the IceCube Collaboration has put Lorentz symmetry to the test and found—yet again—that neutrinos behave as expected. The results, published in Nature Physics, are the most stringent limits to date in the neutrino sector on the existence of a Lorentz violating field.
Observations made by the IceCube Neutrino Observatory at the Amundsen–Scott South Pole Station and confirmed by telescopes around the globe and in Earth’s orbit have for the first time provided evidence for a known blazar as a source of high-energy neutrinos. These results are presented in two papers published this week in the journal Science.
The IceCube Collaboration has tested a few models of heavy dark matter and found no evidence that the high-energy neutrinos can be attributed to the decay of dark matter particles. This nondetection resulted in a new lower limit for the lifetime of dark matter particles with a mass of 10 TeV or above. The paper summarizing these results has just been submitted to the European Physical Journal C.
The fifth edition of the IceCube Masterclass hosted over 300 students at 17 institutions in Belgium, Denmark, Germany, Switzerland, and the United States.
With better and larger neutrino telescopes on the horizon, researchers are now designing more efficient analysis techniques that will boost our understanding of neutrinos and advance searches for new physics, including additional neutrino flavors or new interactions. These techniques not only provide more accurate and robust results but also reduce expenses and time in computation that could limit improvements in the design of new detectors or the discovery potential of existing facilities. Details of these new techniques are given in a paper by the IceCube-Gen2 Collaboration submitted this week to Computer Physics Communications.
Although fast radio bursts’ (FRBs) progenitors are supposed to be compact and perhaps catastrophic cosmic events that may also produce neutrinos, IceCube has not detected any such neutrinos that could be associated with a known FRB in six years of data. These results are far from precluding the eventual detection of neutrinos from FRBs in the future, but they have set the best limits yet on how many are emitted. The results have been submitted today to ''The Astrophysical Journal''.
Neutrinos are abundant subatomic particles that are famous for passing through anything and everything, only very rarely interacting with matter. Now, scientists have demonstrated that the Earth stops very energetic neutrinos—they do not go through everything. The study is published online today by the journal Nature.
In a joint effort by the ANTARES, IceCube, Pierre Auger, LIGO, and Virgo collaborations, scientists have searched for neutrino emission from this merger. The search looked for neutrinos in the GeV to EeV energy range and did not find any neutrino in directional coincidence with the host galaxy. The nondetection agrees well with our expectation from short GRB models of observations at a large off-axis angle, which is most likely the case for the GRB detected in conjunction with GW170817. These results have just been submitted to The Astrophysical Journal.
In a new search for nonstandard neutrino interactions, the IceCube Collaboration has tested theories that introduce heavy bosons, such as some Grand Unified Theories. The study resulted in new constraints on these models, which are among the world’s best limits for nonstandard interactions in the muon-tau neutrino sector. These results have just been submitted to Physical Review D.
This week, the IceCube Collaboration presents a new measurement of the oscillation parameters that for the first time is competitive with the best measurements to date. These results have just been submitted to Physical Review Letters.
The IceCube Collaboration presents a new search for neutrino emission associated with the galactic plane with seven years of IceCube data. The results, submitted to The Astrophysical Journal, are not conclusive but set new constraints on the possible galactic contribution.
The astrophysical neutrino flux observed by IceCube has been the focus of many studies, by both the IceCube Collaboration and other scientists around the world. The collaboration announces today a new study that finds an excess of muon neutrinos at energies above 126 TeV, which is compatible with recent measurements of the astrophysical neutrino flux and constitutes the first model-independent measurement of this flux. These results have been submitted recently to the European Physical Journal C.
It’s that time of the year. Down at the South Pole, our team is in the darkness of the austral winter, enjoying beautiful auroras while monitoring IceCube data taking. Up north, the team has completed all updates and checks to the new data systems running live in the IceCube Lab (ICL), sitting on top of the IceCube detector on Antarctica’s surface.
IceCube has proven to be a champion detector for indirect searches of dark matter using neutrinos. In the most recent study, the collaboration sets the best limits on a neutrino signal from dark matter particles with masses between 10 and 100 GeV. These results have recently been submitted to the European Physical Journal C.
The IceCube Collaboration presents the first search for neutrino sources using cascade events with an energy above 1 TeV. Although no significant clustering was observed, this method provides an independent technique to search for astrophysical neutrino sources. These results have just been submitted to The Astrophysical Journal.
The IceCube, ANTARES, Virgo and LIGO collaborations have joined efforts to look for neutrino emission from the second gravitational wave (GW) event as well as from a previous GW candidate. IceCube and ANTARES searched for neutrinos in temporal coincidence and from the directional constraints provided by LIGO. Within 500 seconds around the two GW signals, no neutrino events were found that come within from the signal region in either detector. These results have recently been submitted to Physical Review D.
The IceCube Collaboration presents an update to previous GRB searches and broadens the search to the Southern Hemisphere using data through May 2015. The inspection of the southern sky increases the sensitivity to the highest-energy neutrinos, which are largely absorbed before reaching IceCube after sailing through the Earth. Researchers looked for neutrino emission in conjunction with prompt gamma-ray emission from 1172 GRBs and did not find any significant correlation with neutrinos detected in IceCube. These results set the strongest constraints yet on GRBs as primary sources of UHECRs. This study has just been submitted to The Astrophysical Journal.
On February 17, 2016, IceCube detected the most significant multiplet since the start of the optical follow-up program: three neutrinos appearing within 100 seconds and consistent with a point source origin. This rare neutrino coincidence has allowed further testing of the capabilities of the IceCube follow-up program, which is able to trigger observations in near real time to search for transient sources. These results have been submitted today to the journal Astronomy & Astrophysics.
The IceCube Collaboration has continued the hunt for sterile neutrinos with a search using lower energy atmospheric neutrinos. This new search looked into three years of IceCube data and again has not found any hint of a light sterile neutrino. These results have been submitted today to Physical Review D.
The IceCube Collaboration has recently presented an update to the search for dark matter annihilation in the sun using the first three years of data with the completed detector. The search, which again did not find evidence of neutrinos originating from dark matter annihilations, has now improved these limits by a factor of 2 to 4. These are again the most stringent limits on the spin-dependent dark-matter–proton scattering for WIMP masses above 50 GeV. This study was submitted to the European Physical Journal C.
New measurements of neutrino oscillations, observed at the IceCube Neutrino Observatory at the South Pole, have shed light on outstanding questions regarding fundamental properties of neutrinos. These new measurements of neutrinos as they change from one type to another while they travel were presented at the American Physical Society Meeting in Washington.
For the first time, the IceCube Collaboration is making public every detail of the only cubic-kilometer neutrino detector to date, from a flasher board in the digital optical modules—aka DOMs—to the calibration processes that allow researchers to measure the properties of neutrinos, or to the IceCube Live website that IceCubers use to monitor what is going on in the detector. The publication, over 70 pages long, has just been submitted to the Journal of Instrumentation.
A new study from the IceCube Collaboration searched in three years of IceCube data for directional clustering of neutrinos around gamma-ray sources associated with blazars from the second Fermi-LAT AGN catalog. Although some enhancements in the observed neutrino rate from these blazars were found in the 3–30 TeV region, all of them are compatible with fluctuations of the atmospheric neutrino background. These results, recently submitted to The Astrophysical Journal, open several new analyses exploring blazars as very high energy neutrino sources.
IceCube’s collaborative efforts with gamma-ray, X-ray, and optical telescopes started long ago. Now, the IceCube, MAGIC and VERITAS collaborations present updates to their follow-up programs that will allow the gamma-ray community to collect data from specific sources during periods when IceCube detects a higher number of neutrinos. Details of the very high energy gamma-ray follow-up program have been submitted to the Journal of Instrumentation.
The IceCube Collaboration has just announced the results of a search for point-like sources using track-like neutrino candidates detected by IceCube over seven years, from 2008 to 2015. No source has been identified, but the sensitivity keeps improving at a fast pace and will allow IceCube to test accurate models that suggest that sources could soon be observed. These results have just been submitted to The Astrophysical Journal.
The IceCube Collaboration has expanded dark matter studies with a search for annihilations in the center of the Earth. Researchers have used one year of data—May 2011 to May 2012—and have not found an excess of neutrinos above the expected background. The results have set new limits on the annihilation rate of WIMPs in the Earth that are an order of magnitude stronger than previous results by AMANDA and that also improve the IceCube spin-independent cross section limits for a WIMP mass of 50 GeV. This study has just been submitted to The European Physical Journal C.
Growing up on a small, secluded hobby farm in southwestern Wisconsin, the night sky played a major role in my upbringing. Since there is almost no light pollution, the night sky was always bright and clear. In the summer months, my bedtime was determined by the time a specific satellite went over the house. Every year, my family would gather up all the blankets in the house and lay outside to watch meteor showers for hours. From a young age, I loved the idea of learning more about the stars and planets, and as I got into high school, I fell in love with physics. My original plan was to become a high school physics teacher, and I found the University of Wisconsin–River Falls (UWRF) not only has a fantastic physics program but is also involved with IceCube. I had heard about IceCube in 2013, when it won Physics World’s Breakthrough of the Year, and working for IceCube became my new goal and dream.
During my summer abroad, I worked with Dr. Jon Dumm, who is searching for an excess of neutrino events originating in the plane of the Milky Way. Dr. Dumm’s analysis is designed to look for a diffuse neutrino flux from the galactic plane in agreement with a map of where pion decay is expected to occur. However, this analysis is sensitive to a neutrino flux from point sources that are not necessarily distributed as the pion decay map predicts. We simulated four possible models of cosmic-ray source density in the galaxy as proxies for possible distributions of unresolved neutrino point sources. In doing so, we established limits on the total flux from various numbers of sources to which the primary pion-decay-based analysis is sensitive.
At the start of the summer, UW-River Falls student Nick Jensen and I set out to create a 1:1000 scale model of the IceCube detector using LEDs to represent DOMs. To do this, we needed a wide assortment of parts to construct the model from the ground up. We spent the first half of the summer trying to gather all the parts needed for building.
In an effort to fill in the blanks of the Standard Model of particle physics, science has been conducting a diligent search for a hypothesized particle known as the “sterile neutrino.” Now, with the latest results from an icy particle detector at the South Pole, scientists are almost certain that there is no such particle.
The IceCube Collaboration is now accumulating more statistics in the search for the sources of very high energy neutrinos, but also to learn more about their nature. In a new study, submitted this week to the Astrophysical Journal, the collaboration reports a substantially improved observation of the diffuse muon neutrino flux in the Northern Hemisphere using six years of IceCube data with about a tenfold increase in statistics. Once more, a clear astrophysical contribution has been found, which at the highest energies excludes a purely atmospheric origin at the 5.6 sigma level. Also, the accuracy of the measurement of the spectral properties has been improved.
The IceCube Collaboration has made public today that a new search for cosmogenic neutrinos resulted in two very high energy neutrinos. These neutrinos, which are found to be of astrophysical origin with a 92.3% probability, include the highest energy neutrino detected to date. While of astrophysical origin, the energy of these neutrinos does not match the expectation for a cosmogenic neutrino flux. The lack of evidence for such events in a search of seven years of IceCube data places very strong constraints on the sources of UHECR. Proton-dominated sources are greatly disfavored, and testing mixed and heavy nuclei cosmic-ray sources will require much bigger instruments, such as an extension of IceCube or radio Askaryan neutrino detectors. These results have been submitted yesterday to Physical Review Letters.
The IceCube Collaboration presents results from a search for sources of high-energy neutrons using four years of data from IceTop, the surface detector array. Researchers have not found any evidence for astrophysical neutrons, but the results have allowed the collaboration to set new limits that constrain the possible galactic neutron sources. These results have just been submitted to the Astrophysical Journal.
The Precision IceCube Next Generation Upgrade (PINGU) is the proposed infill extension in a region at the center of the IceCube Neutrino Observatory that will lower the energy threshold to a few GeV, dramatically increasing both the number of GeV-scale neutrinos detected by IceCube and, more importantly, the precision with which they are measured.
The IceCube Collaboration presents a new search for dark matter annihilation from the galactic center and halo using cascade events, i.e., particle showers created by the interaction of electron and tau neutrinos and Z-boson mediated muon neutrinos. Scientists searched for interactions starting in the DeepCore subarray between May 2011 and May 2012 and found no neutrino excess with respect to the background-only hypothesis, which allowed them to derive upper limits on dark matter candidates with masses between 30 GeV and 10 TeV. These results have been submitted today to the European Physical Journal C.
“On behalf of the operations group, I’m happy to report that as of run 127950 on 2016-05-20, 20:38:47 UTC, we have started the IC86-2016 physics run.” With these words, every IceCuber learned that we were entering a new year of data for IceCube.
The IceCube Collaboration has performed two independent searches for light sterile neutrinos, both with one year of data, searching for sterile neutrinos in the energy range between approximately 320 GeV and 20 TeV. IceCube has not found any anomalous disappearance of muon neutrinos and has placed new exclusion limits on the parameter space of the 3+1 model, a scenario with only one sterile neutrino. These results have been submitted today to Physical Review Letters.
Today, the IceCube Collaboration presents a new technique to lower the energy threshold for neutrino detection while keeping a pointing resolution to within less than a degree. IceCube researchers have used this technique in a joint search with data from a previous analysis using throughgoing muon neutrinos. No point source has been found, but sensitivity for searches below 100 TeV has been improved by a factor of ten.
The IceCube Collaboration is updating the cosmic ray anisotropy maps using 318 billion cosmic-ray-induced muon events detected in IceCube between May 2009 and May 2015. The larger data sample allowed discerning new regions in the anisotropy maps, which shed some light on the physical processes that stir up the variations in the arrival direction of cosmic rays. These results have been recently submitted to The Astrophysical Journal.
The detection of the first gravitational wave (GW) event by LIGO represents one of the greatest scientific breakthroughs of recent years. After receiving the gravitational wave alert in September 2015 from the Advanced LIGO detector, the IceCube and ANTARES neutrino telescopes analyzed the data they had recorded at the same time in order to search for neutrinos that might have been emitted from the same event. Neither search identified any neutrinos that could be associated with the burst. These results set the first limits on neutrino emission from a GW transient event.
Today, the IceCube Collaboration announces a new search for neutrino emission from GRBs with a first-ever search that covers all flavors and the full sky. Five events were found to have a low-significance correlation with five GRBs. Consequently, the analysis places tight constraints on current models of neutrino and ultra-high-energy cosmic ray (UHECR) production in GRBs. These results have just been submitted to The Astrophysical Journal.
In 2013, the IceCube Collaboration published the world’s best limits on the spin-dependent cross section for weakly interacting dark matter particles. They were derived from the non-observation of annihilation into neutrinos of dark matter gravitationally trapped by the Sun.
Now, the collaboration presents a new likelihood formalism that allows easy integration of any neutrino telescope data into analyses of dark matter theories.
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 cosmic rays in these two cosmic-ray observatories. 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.
New results submitted today to the Astrophysical Journal are the outcome of a combined search for neutrino point sources performed by the ANTARES and IceCube collaborations. No source has been identified, but the combined search improves the sensitivity to point sources by up to a factor of two, which delivers more stringent upper limits on the flux for the candidate sources considered in this analysis.
The IceCube Collaboration today presents a search for relativistic and mildly relativistic monopoles using two years of data. No monopole candidate was observed, but IceCube data allowed setting very stringent limits for the range of velocities studied. These results have been submitted today to European Physical Journal C.
Neutrino physicists spend a lot of time in the dark. As a figurative statement this reflects how difficult neutrinos are to understand, but it also reveals the literal sense that we work with experiments that do not see a lot of sun—and it’s not just the South Pole, it’s also in mines, tunnels, and deep underwater in seas and lakes. But just like a rare neutrino interaction, every so often a brief flash of light offers some new truth about the nature of our universe.
The Physics Department of UW–River Falls hosts summer internships for young college students that allow them to engage in IceCube and other polar science projects. Over the 10-week internship, they become a member of the team, where they learn to program and to tackle challenging scientific questions. And, as you will read here, they also get a chance to share their experience.
Today the IceCube Collaboration has presented a search for tau neutrinos at energies above 214 TeV that, although it did not find any events, allowed setting upper limits on the astrophysical tau neutrino flux. This search sets limits on tau neutrinos at energies three orders of magnitude lower than the energies reached by previous dedicated tau neutrino searches. And more importantly, the results now submitted to Physical Review D also prove that tau neutrino searches in IceCube are reaching the sensitivity for a potential discovery.
In a paper submitted today to the Astrophysical Journal, the IceCube Collaboration presents results of a search for astrophysical sources of transient neutrino emission using a sample of low-energy—30 to 300 GeV—muon neutrino events from DeepCore. Although no source is singled out, the study sets limits on soft-spectra models, such as energetic or nearby choked GRBs.
The “IRES: U.S.-European International Research Experience-Particle Astrophysics for Undergraduates” program, funded by NSF and led by the University of Wisconsin–River Falls, brought us to Johannes Gutenburg University in Mainz, Germany, this summer to work with Professor Lutz Köpke and Professor Sebastian Böser.
International Research Experiences for Students (IRES) is a program funded by the National Science Foundation to support active participation of US undergraduates in international research projects. Laura Lusardi from New Richmond, WI, and Kelsey Kolell from Fond du Lac, WI, participated in the IRES program through UW–River Falls to work on IceCube research for the summer.
We are both third-year undergraduate students, studying physics at the University of Wisconsin–River Falls. This summer, we had the wonderful opportunity to travel to Germany through IRES to work with IceCube researchers. Even though we both ended up attending the same university, we took wildly different paths to get here.
When I came to Yale three years ago, I did not expect to major in physics. Yet, after taking my first class in the subject, it was not long before its fundamental nature and incredible universality had reeled me in for good. Since then, I have sought out opportunities to explore the field and learn what it really means to be a physicist. I joined Assistant Professor Reina Maruyama’s lab this past January and a few months later found myself working on DM-Ice and IceCube. Now, as I gear up for my final year of college, I am spending my summer on campus, conducting research on coincident muon events between the enormous IceCube (1 cubic km) and comparatively miniature (2,309 cubic cm) DM-Ice17 detectors.
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.
The Astrophysical Multimessenger Observatory Network (AMON) will link existing and future high-energy astrophysical observatories into a single virtual system, enabling near real-time coincidence searches for multimessenger astrophysical transients and their electromagnetic counterparts and providing alerts to follow-up observatories.
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 of the astrophysical neutrino flux.
In a new study presented a few days ago, the IceCube Collaboration reports the potential of atmospheric muons detected in IceCube to help our understanding of important properties of cosmic rays in a wide range of energies. These muons are also shown to be useful for investigating systematic uncertainties in neutrino studies in IceCube. Measurements of the composition of primary cosmic rays, the high-energy spectrum of muons, and the prompt flux are three of the highlights of this paper, which was submitted last Friday to Astroparticle Physics.
On March 30, 2012, IceCube detected two high-energy neutrino events. IceCube immediately sent an alert to several optical and X-ray telescopes—the Robotic Optical Transient Search Experiment (ROTSE), the Palomar Transient Factory (PTF) and the Swift satellite—and a core-collapse supernova was discovered in the PTF images. However, physicists have shown that this was a coincidental discovery and that this supernova is not likely to be the source of the neutrinos in IceCube. These results have been submitted today to the Astrophysical Journal and are the outcome of a joint study between the IceCube Collaboration and members of the PTF Collaboration, the Swift Collaboration and the Pan-STARRS1 Science Consortium.
In a new analysis of the IceCube Collaboration, a search for dark matter annihilation at the Galactic Center is presented using data from May 2010 to May 2011. The highest density of dark matter in the Milky Way is anticipated to concentrate in its center. Dark-matter self-annihilation should then produce a flux of muon neutrinos and other particles that peaks in the direction of this region, which is seen in the Southern Hemisphere by IceCube. The search did not find a neutrino excess, and the researchers have set new limits on the dark-matter self-annihilation cross section. These results have been submitted today to European Physical Journal C.
Not everyone begins a new year on January 1, right? That includes IceCubers, who decided a while ago that mid May would be a good time to start a new year of data for the South Pole neutrino observatory.
The IC86-2014 physics run ended on May 18, 2015, wrapping up another successful year for the IceCube detector.
In a new analysis by the IceCube Collaboration, the atmospheric electron neutrino spectrum is measured at energies between 0.1 TeV and 100 TeV, extending previous measurements to higher energies and yielding improved precision. The results, which have been submitted to Physical Review D, find good agreement with models of the conventional electron neutrino flux.
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. 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.
Searches with IceCube have so far persistently shown us that more data is needed to reveal the first cosmic ray source. But IceCube researchers are convinced that success also requires a resolute determination to exploit IceCube data in every possible manner. In a new study submitted today to the Astrophysical Journal, the collaboration presents a search for time-dependent astrophysical neutrino sources that did not find any evidence for their existence. The study did however make it possible to set upper limits on the neutrino flux from several source candidates and has proven IceCube’s capabilities for long-term monitoring of sources triggered by multiwavelength information from several experiments.
In a new measurement of the flavor ratio of astrophysical neutrinos, submitted today to Physical Review Letters, the IceCube Collaboration has found good agreement with the standard source model. The collaboration also sets limits on nonstandard flavor compositions, which could be a signature for new physics in the neutrino sector, such as neutrino decay or sterile neutrinos.
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.
Last year, an initial measurement of the neutrino oscillation parameters was a hint that IceCube could become an important detector for studying neutrino oscillations. Today, the IceCube Collaboration has submitted new results to Physical Review Letters that present an improved measurement of the oscillation parameters, via atmospheric muon neutrino disappearance, which is compatible and comparable in precision to those of dedicated oscillation experiments such as MINOS, T2K or Super-Kamiokande.
The IceCube Collaboration has expanded the search for neutrino interactions in IceCube, lowering the range of deposited energy down to 1 TeV. The goal was a better understanding of the different contributions to the neutrino flux in IceCube and hopefully to measure the charmed-meson component for the first time. The results of this study have been submitted today to Physical Review D.
The IceCube Collaboration has submitted a paper today to the European Physical Journal C describing a new analysis scheme for the measurement of the atmospheric neutrino spectrum with the IceCube detector.
In a new analysis by the IceCube Collaboration, a search for faint point sources, by looking for small-scale anisotropies in the diffuse neutrino flux, was found to be consistent with the background expectation. These results have just been submitted to Astroparticle Physics.
In a joint analysis by the IceCube, LIGO and Virgo collaborations to be submitted to the journal Physical Review D, researchers aimed to identify GW events and high-energy neutrinos that could originate from the same astrophysical source and to determine their joint significance. No significant coincident events were found, but the search allowed researchers to derive upper limits on the rate of joint sources for a range of source emission parameters.
The quest for galactic halo dark matter includes high-energy neutrino searches that might be produced by the self-annihilation of dark matter particles in our galaxy. If this is the case, IceCube should observe a characteristic anisotropy in the neutrino flux due to the additional dark-matter induced neutrinos. So far, the IceCube Collaboration has not found any significant deviation from the background expectation, following new results that have been submitted today to The European Physical Journal C.
The IceCube Collaboration presents several searches for extended and point-like astrophysical neutrino sources using four years of data. No evidence of neutrino emission has been found yet, but a few models have been ruled out. This research has been submitted today to The Astrophysical Journal.
Strong evidence for a very high energy neutrino flux of extraterrestrial origin was found in November 2013, and new data from IceCube now confirms the discovery. Once more, the Antarctic detector brings us still the highest energy neutrino ever observed.
In a paper recently published in Science Express, cosmic ray data from IceCube was used alongside observations from NASA’s Interstellar Boundary Explorer, or IBEX, in a study of the magnetic fields that surround our solar system.
In a new paper submitted to The European Physical Journal C, the IceCube Collaboration presents a search for non-relativistic (slow) magnetic monopoles that, despite being fruitless, has set the best experimental limits for a wide range of assumed speeds and catalysis cross sections.
PINGU, the Precision IceCube Next Generation Upgrade, proposes a extension inside the current IceCube array designed to measure the mass of the three known neutrino types.
The IceCube project has been awarded the 2013 Breakthrough of the Year by the British magazine Physics World. The Antarctic observatory has been selected for making the first observation of cosmic neutrinos, but also for overcoming the many challenges of creating and operating a colossal detector deep under the ice at the South Pole.
In a paper recently published in the Journal of Glaciology, the IceCube Collaboration presents a study of South Pole climate over the past 100,000 years, using high-resolution 3D laser images of the ice sheet.
In a new study, the IceCube Collaboration searches for neutrino-induced particle showers in one year of data taken during the construction phase of IceCube, when about half the detector was operational. Above 100 TeV, a 2.7σ excess of events was found, which is consistent with results published by the IceCube Collaboration in Science. The current paper has been submitted to the journal Physical Review D.
In an analysis published today, the IceCube Collaboration reports on a search for a diffuse astrophysical neutrino signal, looking at high-energy upward-going muon tracks, with data taken between May 2009 and May 2010, when the detector was running in its 59-string configuration. The search found a high-energy neutrino excess of 1.8σ compared to the background scenario of a pure conventional atmospheric model, a measurement consistent with the astrophysical neutrino flux described in Science. The results of this research have been submitted to Physical Review D.
The IceCube Neutrino Observatory is a demonstration of the power of the human passion for discovery, where scientific ingenuity meets technological innovation. Today, nearly 25 years after the pioneering idea of detecting neutrinos in ice, the IceCube Collaboration announces the observation of 28 very high-energy particle events that constitute the first solid evidence for astrophysical neutrinos from cosmic accelerators. Details of the research appear in an article published tomorrow, November 22, in Science.
The IceCube collaboration presents new results that rule out the possibility—at a confidence level greater than 90%—that the two PeV events detected in IceCube are cosmogenic neutrinos. However, the long exposure of the analyzed data, from May 2010 to May 2012, and the lack of detected events with higher energies, have allowed a new probe into the cosmogenic neutrino flux, which has been used to set the most stringent limit for the energy range from 1 PeV to 10 EeV. This analysis has just been submitted to the journal Physical Review D.
A new study by the IceCube Collaboration shows that the muon track reconstruction performed in the early stages of the analysis can be significantly improved by using robust statistical methods to estimate particle trajectories through the detector. The new algorithm results in a 13% gain in the angular resolution of the muon track and a 98% accuracy rate in determining the number of muons in coincident events. The paper has just been submitted to Nuclear Instruments and Methods in Physics Research Section A.
A search for neutrino point sources using throughgoing muons in IceCube has not found any excess of neutrinos above the atmospheric background in any given direction in the sky. Neither did dedicated searches of a priori selected objects. However, IceCube data provide insights into the nature of cosmic ray sources even from non-discovery results. These results have been submitted today to The Astrophysical Journal.
The IceCube Collaboration publishes today a new measurement of the all-particle cosmic ray energy spectrum in the energy range from 1.6 PeV to 1.3 EeV using data from IceTop, the surface component of the IceCube Neutrino Observatory. The measured spectrum exhibits clear deviations from power law behavior. These resultshave just been submitted to Physical Review D.
The IceCube Collaboration presents the results of a first search for self-annihilating dark matter in nearby galaxies and galaxy clusters. This analysis has been submitted today to Physical Review D.
A recent measurement of the Moon shadow in TeV cosmic rays with the IceCube telescope sets an upper limit on the detector’s absolute pointing accuracy to 0.2 degrees. The IceCube Collaboration presents these results in a paper submitted today to Physical Review D.
The IceCube Neutrino Observatory, which comprises the IceCube and DeepCore detectors, has been designed to contribute heavily to our understanding of neutrino physics. In a paper submitted today to Physical Review Letters, the IceCube Collaboration has announced the first statistically significant detection of neutrino oscillations in the high-energy region (20–100 GeV).
In a paper submitted to Physical Review Letters, the IceCube Collaboration confirms highest energy neutrinos ever observed.
From its vantage point at the geographic South Pole in Antarctica, the IceCube Neutrino Observatory is uniquely positioned to see neutrinos—mysterious, nearly massless, difficult-to-detect particles that are plentiful but little understood.
IceCube DeepCore "sub-detector" sees high-energy neutrino oscillations.
Using data from the IceCube Neutrino Observatory, astrophysicists Nathan Whitehorn and Pete Redl searched for neutrinos coming from the direction of known GRBs. And they found nothing.
Their result, appearing today in the journal Nature, challenges one of the two leading theories for the origin of the highest energy cosmic rays.
Although cosmic rays were discovered 100 years ago, their origin remains one of the most enduring mysteries in physics. Now, the IceCube Neutrino Observatory, a massive detector in Antarctica, is honing in on how the highest energy cosmic rays are produced.
The IceCube collaboration published a paper entitled "Search for dark matter from the Galactic halo with the IceCube Neutrino Telescope," detailing the collaboration's search for Dark Matter with IceCube.
Nature writer Dieter H. Hartmann sums up the absence of evidence of neutrinos from Gamma Ray Bursts as detailed in an IceCube publication in Physical Review of Letters.
Researcher William C. Lewis discusses observed differences between neutrino and antineutrino disappearance, what that might mean for our understanding of th Universe, and the role IceCube can play in discovering an answer
IceCube collaborator and Japanese resident Shigeru Yoshida took advantage of an opportunity to help out his country by volunteering to scan residents after they spent time inside the Fukushima hot zone gathering belongings from their hastily evacuated homes. His first hand account of the area after a 9.0 magnitude earthquake compromised the nuclear power plant on March 11 is below.
Wired Science spoke with University of Wisconsin-Madison PhD candidate Nathan Whitehorn about what IceCube hasn't seen, and how that helps us set boundaries on what we know about the Universe.
This German-language publication covers the IceCube project and other neutrino detection experiments, with quotes from IceCube collaborator Christian Spiering (DESY) and advisory board member Uli Katz (U. of Erlangen).