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1.
  • Aartsen, M. G., et al. (author)
  • Cosmic ray spectrum and composition from PeV to EeV using 3 years of data from IceTop and IceCube
  • 2019
  • In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 100:8
  • Journal article (peer-reviewed)abstract
    • We report on measurements of the all-particle cosmic ray energy spectrum and composition in the PeV to EeV energy range using 3 years of data from the IceCube Neutrino Observatory. The IceTop detector measures cosmic ray induced air showers on the surface of the ice, from which the energy spectrum of cosmic rays is determined by making additional assumptions about the mass composition. A separate measurement is performed when IceTop data are analyzed in coincidence with the high-energy muon energy loss information from the deep in-ice IceCube detector. In this measurement, both the spectrum and the mass composition of the primary cosmic rays are simultaneously reconstructed using a neural network trained on observables from both detectors. The performance and relative advantages of these two distinct analyses are discussed, including the systematic uncertainties and the dependence on the hadronic interaction models, and both all-particle spectra as well as individual spectra for elemental groups are presented.
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2.
  • Aartsen, M. G., et al. (author)
  • A Search for IceCube Events in the Direction of ANITA Neutrino Candidates
  • 2020
  • In: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 892:1
  • Journal article (peer-reviewed)abstract
    • During the first three flights of the Antarctic Impulsive Transient Antenna (ANITA) experiment, the collaboration detected several neutrino candidates. Two of these candidate events were consistent with an ultra-high-energy upgoing air shower and compatible with a tau neutrino interpretation. A third neutrino candidate event was detected in a search for Askaryan radiation in the Antarctic ice, although it is also consistent with the background expectation. The inferred emergence angle of the first two events is in tension with IceCube and ANITA limits on isotropic cosmogenic neutrino fluxes. Here we test the hypothesis that these events are astrophysical in origin, possibly caused by a point source in the reconstructed direction. Given that any ultra-high-energy tau neutrino flux traversing the Earth should be accompanied by a secondary flux in the TeV-PeV range, we search for these secondary counterparts in 7 yr of IceCube data using three complementary approaches. In the absence of any significant detection, we set upper limits on the neutrino flux from potential point sources. We compare these limits to ANITA's sensitivity in the same direction and show that an astrophysical explanation of these anomalous events under standard model assumptions is severely constrained regardless of source spectrum.
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3.
  • Aartsen, M. G., et al. (author)
  • A Search for Neutrino Point-source Populations in 7 yr of IceCube Data with Neutrino-count Statistics
  • 2020
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 893:2
  • Journal article (peer-reviewed)abstract
    • The presence of a population of point sources in a data set modifies the underlying neutrino-count statistics from the Poisson distribution. This deviation can be exactly quantified using the non-Poissonian template fitting technique, and in this work we present the first application of this approach to the IceCube high-energy neutrino data set. Using this method, we search in 7 yr of IceCube data for point-source populations correlated with the disk of the Milky Way, the Fermi bubbles, the Schlegel, Finkbeiner, and Davis dust map, or with the isotropic extragalactic sky. No evidence for such a population is found in the data using this technique, and in the absence of a signal, we establish constraints on population models with source-count distribution functions that can be described by a power law with a single break. The derived limits can be interpreted in the context of many possible source classes. In order to enhance the flexibility of the results, we publish the full posterior from our analysis, which can be used to establish limits on specific population models that would contribute to the observed IceCube neutrino flux.
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4.
  • Aartsen, M. G., et al. (author)
  • Characteristics of the Diffuse Astrophysical Electron and Tau Neutrino Flux with Six Years of IceCube High Energy Cascade Data
  • 2020
  • In: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 125:12
  • Journal article (peer-reviewed)abstract
    • We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (similar to 90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be gamma = 2.53 +/- 0.07 and a flux normalization for each neutrino flavor of phi(astro) = 1.66(-0.27)(+0.25) at E-0 = 100 TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices gamma <= 2.28 at >= 3 sigma significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below similar to 100 TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value >= 0.06). The sizable and smooth flux measured below similar to 100 TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.
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5.
  • Aartsen, M. G., et al. (author)
  • Constraints on neutrino emission from nearby galaxies using the 2MASS redshift survey and IceCube
  • 2020
  • In: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :7
  • Journal article (peer-reviewed)abstract
    • The distribution of galaxies within the local universe is characterized by anisotropic features. Observatories searching for the production sites of astrophysical neutrinos can take advantage of these features to establish directional correlations between a neutrino dataset and overdensities in the galaxy distribution in the sky. The results of two correlation searches between a seven-year time-integrated neutrino dataset from the IceCube Neutrino Observatory, and the 2MASS Redshift Survey (2MRS) catalog are presented here. The first analysis searches for neutrinos produced via interactions between diffuse intergalactic Ultra-High Energy Cosmic Rays (UHECRs) and the matter contained within galaxies. The second analysis searches for low-luminosity sources within the local universe, which would produce subthreshold multiplets in the IceCube dataset that directionally correlate with galaxy distribution. No significant correlations were observed in either analyses. Constraints are presented on the flux of neutrinos originating within the local universe through diffuse intergalactic UHECR interactions, as well as on the density of standard candle sources of neutrinos at low luminosities.
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6.
  • Aartsen, M. G., et al. (author)
  • Design and performance of the first IceAct demonstrator at the South Pole
  • 2020
  • In: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 15:2
  • Journal article (peer-reviewed)abstract
    • In this paper we describe the first results of IceAct, a compact imaging air-Cherenkov telescope operating in coincidence with the IceCube Neutrino Observatory (IceCube) at the geographic South Pole. An array of IceAct telescopes (referred to as the IceAct project) is under consideration as part of the IceCube-Gen2 extension to IceCube. Surface detectors in general will be a powerful tool in IceCube-Gen2 for distinguishing astrophysical neutrinos from the dominant backgrounds of cosmic-ray induced atmospheric muons and neutrinos: the IceTop array is already in place as part of IceCube, but has a high energy threshold. Although the duty cycle will be lower for the IceAct telescopes than the present IceTop tanks, the IceAct telescopes may prove to be more effective at lowering the detection threshold for air showers. Additionally, small imaging air-Cherenkov telescopes in combination with IceTop, the deep IceCube detector or other future detector systems might improve measurements of the composition of the cosmic ray energy spectrum. In this paper we present measurements of a first 7-pixel imaging air Cherenkov telescope demonstrator, proving the capability of this technology to measure air showers at the South Pole in coincidence with IceTop and the deep IceCube detector.
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7.
  • Aartsen, M. G., et al. (author)
  • Efficient propagation of systematic uncertainties from calibration to analysis with the SnowStorm method in IceCube
  • 2019
  • In: Journal of Cosmology and Astroparticle Physics. - : IOP PUBLISHING LTD. - 1475-7516. ; :10
  • Journal article (peer-reviewed)abstract
    • Efficient treatment of systematic uncertainties that depend on a large number of nuisance parameters is a persistent difficulty in particle physics and astrophysics experiments. Where low-level effects are not amenable to simple parameterization or re-weighting, analyses often rely on discrete simulation sets to quantify the effects of nuisance parameters on key analysis observables. Such methods may become computationally untenable for analyses requiring high statistics Monte Carlo with a large number of nuisance degrees of freedom, especially in cases where these degrees of freedom parameterize the shape of a continuous distribution. In this paper we present a method for treating systematic uncertainties in a computationally efficient and comprehensive manner using a single simulation set with multiple and continuously varied nuisance parameters. This method is demonstrated for the case of the depth-dependent effective dust distribution within the IceCube Neutrino Telescope.
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8.
  • Aartsen, M. G., et al. (author)
  • eV-Scale Sterile Neutrino Search Using Eight Years of Atmospheric Muon Neutrino Data from the IceCube Neutrino Observatory
  • 2020
  • In: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 125:14
  • Journal article (peer-reviewed)abstract
    • The results of a 3 + 1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100 eV(2). The best-fit point is found to be at sin(2)(2 theta(24)) = 0.10 and Delta m(41)(2) = 4.5 eV(2), which is consistent with the no sterile neutrino hypothesis with a p value of 8.0%.
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9.
  • Aartsen, M. G., et al. (author)
  • Follow-up of Astrophysical Transients in Real Time with the IceCube Neutrino Observatory
  • 2021
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 910:1
  • Journal article (peer-reviewed)abstract
    • In multi-messenger astronomy, rapid investigation of interesting transients is imperative. As an observatory with a 4 pi steradian field of view, and similar to 99% uptime, the IceCube Neutrino Observatory is a unique facility to follow up transients, as well as to provide valuable insights for other observatories and inform their observational decisions. Since 2016, IceCube has been using low-latency data to rapidly respond to interesting astrophysical events reported by the multi-messenger observational community. Here, we describe the pipeline used to perform these followup analyses, and provide a summary of the 58 analyses performed as of July 2020. We find no significant signal in the first 58 analyses performed. The pipeline has helped inform various electromagnetic observation strategies, and has constrained neutrino emission from potential hadronic cosmic accelerators.
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10.
  • Aartsen, M. G., et al. (author)
  • IceCube-Gen2 : the window to the extreme Universe
  • 2021
  • In: Journal of Physics G. - : Institute of Physics Publishing (IOPP). - 0954-3899 .- 1361-6471. ; 48:6
  • Journal article (peer-reviewed)abstract
    • The observation of electromagnetic radiation from radio to gamma-ray wavelengths has provided a wealth of information about the Universe. However, at PeV (10(15) eV) energies and above, most of the Universe is impenetrable to photons. New messengers, namely cosmic neutrinos, are needed to explore the most extreme environments of the Universe where black holes, neutron stars, and stellar explosions transform gravitational energy into non-thermal cosmic rays. These energetic particles have millions of times higher energies than those produced in the most powerful particle accelerators on Earth. As neutrinos can escape from regions otherwise opaque to radiation, they allow an unique view deep into exploding stars and the vicinity of the event horizons of black holes. The discovery of cosmic neutrinos with IceCube has opened this new window on the Universe. IceCube has been successful in finding first evidence for cosmic particle acceleration in the jet of an active galactic nucleus. Yet, ultimately, its sensitivity is too limited to detect even the brightest neutrino sources with high significance, or to detect populations of less luminous sources. In this white paper, we present an overview of a next-generation instrument, IceCube-Gen2, which will sharpen our understanding of the processes and environments that govern the Universe at the highest energies. IceCube-Gen2 is designed to: (a) Resolve the high-energy neutrino sky from TeV to EeV energies (b) Investigate cosmic particle acceleration through multi-messenger observations (c) Reveal the sources and propagation of the highest energy particles in the Universe (d) Probe fundamental physics with high-energy neutrinos IceCube-Gen2 will enhance the existing IceCube detector at the South Pole. It will increase the annual rate of observed cosmic neutrinos by a factor of ten compared to IceCube, and will be able to detect sources five times fainter than its predecessor. Furthermore, through the addition of a radio array, IceCube-Gen2 will extend the energy range by several orders of magnitude compared to IceCube. Construction will take 8 years and cost about $350M. The goal is to have IceCube-Gen2 fully operational by 2033. IceCube-Gen2 will play an essential role in shaping the new era of multi-messenger astronomy, fundamentally advancing our knowledge of the high-energy Universe. This challenging mission can be fully addressed only through the combination of the information from the neutrino, electromagnetic, and gravitational wave emission of high-energy sources, in concert with the new survey instruments across the electromagnetic spectrum and gravitational wave detectors which will be available in the coming years.
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11.
  • Aartsen, M. G., et al. (author)
  • IceCube Search for Neutrinos Coincident with Compact Binary Mergers from LIGO-Virgo's First Gravitational-wave Transient Catalog
  • 2020
  • In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 898:1, s. L10-
  • Journal article (peer-reviewed)abstract
    • Using the IceCube Neutrino Observatory, we search for high-energy neutrino emission coincident with compact binary mergers observed by the LIGO and Virgo gravitational-wave (GW) detectors during their first and second observing runs. We present results from two searches targeting emission coincident with the sky localization of each GW event within a 1000 s time window centered around the reported merger time. One search uses a model-independent unbinned maximum-likelihood analysis, which uses neutrino data from IceCube to search for pointlike neutrino sources consistent with the sky localization of GW events. The other uses the Low-Latency Algorithm for Multi-messenger Astrophysics, which incorporates astrophysical priors through a Bayesian framework and includes LIGO-Virgo detector characteristics to determine the association between the GW source and the neutrinos. No significant neutrino coincidence is seen by either search during the first two observing runs of the LIGO-Virgo detectors. We set upper limits on the time-integrated neutrino emission within the 1000 s window for each of the 11 GW events. These limits range from 0.02 to 0.7 . We also set limits on the total isotropic equivalent energy, E-iso, emitted in high-energy neutrinos by each GW event. These limits range from 1.7 x 10(51) to 1.8 x 10(55) erg. We conclude with an outlook for LIGO-Virgo observing run O3, during which both analyses are running in real time.
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12.
  • Aartsen, M. G., et al. (author)
  • In-situ calibration of the single-photoelectron charge response of the IceCube photomultiplier tubes
  • 2020
  • In: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 15:6
  • Journal article (peer-reviewed)abstract
    • We describe an improved in-situ calibration of the single-photoelectron charge distributions for each of the in-ice Hamamatsu Photonics R7081-02[MOD] photomultiplier tubes in the IceCube Neutrino Observatory. The characterization of the individual PMT charge distributions is important for PMT calibration, data and Monte Carlo simulation agreement, and understanding the effect of hardware differences within the detector. We discuss the single photoelectron identification procedure and how we extract the single-photoelectron charge distribution using a deconvolution of the multiple-photoelectron charge distribution.
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13.
  • Aartsen, M. G., et al. (author)
  • Search for PeV Gamma-Ray Emission from the Southern Hemisphere with 5 Yr of Data from the IceCube Observatory
  • 2020
  • In: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 891:1
  • Journal article (peer-reviewed)abstract
    • The measurement of diffuse PeV gamma-ray emission from the Galactic plane would provide information about the energy spectrum and propagation of Galactic cosmic rays, and the detection of a pointlike source of PeV gamma-rays would be strong evidence for a Galactic source capable of accelerating cosmic rays up to at least a few PeV. This paper presents several unbinned maximum-likelihood searches for PeV gamma-rays in the Southern Hemisphere using 5 yr of data from the IceTop air shower surface detector and the in-ice array of the IceCube Observatory. The combination of both detectors takes advantage of the low muon content and deep shower maximum of gamma-ray air showers and provides excellent sensitivity to gamma-rays between similar to 0.6 and 100 PeV. Our measurements of pointlike and diffuse Galactic emission of PeV gamma-rays are consistent with the background, so we constrain the angle-integrated diffuse gamma-ray flux from the Galactic plane at 2 PeV to 2.61 x 10(-19) cm(-2) s(-1) TeV-1 at 90% confidence, assuming an E-3 spectrum, and we estimate 90% upper limits on pointlike emission at 2 PeV between 10(-21) and 10(-20) cm(-2) s(-1) TeV-1 for an E-2 spectrum, depending on decl. Furthermore, we exclude unbroken power-law emission up to 2 PeV for several TeV gamma-ray sources observed by the High Energy Spectroscopic System and calculate upper limits on the energy cutoffs of these sources at 90% confidence. We also find no PeV gamma-rays correlated with neutrinos from IceCube's high-energy starting event sample. These are currently the strongest constraints on PeV gamma-ray emission.
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14.
  • Aartsen, M. G., et al. (author)
  • Searching for eV-scale sterile neutrinos with eight years of atmospheric neutrinos at the IceCube Neutrino Telescope
  • 2020
  • In: Physical Review D. - : AMER PHYSICAL SOC. - 1550-7998 .- 1550-2368. ; 102:5
  • Journal article (peer-reviewed)abstract
    • We report in detail on searches for eV-scale sterile neutrinos, in the context of a 3 + 1 model, using eight years of data from the IceCube Neutrino Telescope. By analyzing the reconstructed energies and zenith angles of 305,735 atmospheric nu(mu) and (nu) over bar (mu) events we construct confidence intervals in two analysis spaces: sin(2)(2 theta(24)) vs Delta m(41)(2) under the conservative assumption theta(34) = 0; and sin(2)(2 theta(24)) vs sin(2)(2 theta(34)) given sufficiently large Delta m(41)(2) that fast oscillation features are unresolvable. Detailed discussions of the event selection, systematic uncertainties, and fitting procedures are presented. No strong evidence for sterile neutrinos is found, and the best-fit likelihood is consistent with the no sterile neutrino hypothesis with a p value of 8% in the first analysis space and 19% in the second.
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15.
  • Aartsen, M. G., et al. (author)
  • Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data
  • 2020
  • In: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 124:5
  • Journal article (peer-reviewed)abstract
    • This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above similar to 1 TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9 sigma after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506 + 056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3 sigma significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.
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16.
  • Ahrens, Maryon, et al. (author)
  • A Search for MeV to TeV Neutrinos from Fast Radio Bursts with IceCube
  • 2020
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 890:2
  • Journal article (peer-reviewed)abstract
    • We present two searches for IceCube neutrino events coincident with 28 fast radio bursts (FRBs) and 1 repeating FRB. The first improves on a previous IceCube analysis-searching for spatial and temporal correlation of events with FRBs at energies greater than roughly 50 GeV-by increasing the effective area by an order of magnitude. The second is a search for temporal correlation of MeV neutrino events with FRBs. No significant correlation is found in either search; therefore, we set upper limits on the time-integrated neutrino flux emitted by FRBs for a range of emission timescales less than one day. These are the first limits on FRB neutrino emission at the MeV scale, and the limits set at higher energies are an order-of-magnitude improvement over those set by any neutrino telescope.
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17.
  • Ahrens, Maryon, et al. (author)
  • IceCube Search for High-energy Neutrino Emission from TeV Pulsar Wind Nebulae
  • 2020
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 898:2
  • Journal article (peer-reviewed)abstract
    • Pulsar wind nebulae (PWNe) are the main gamma-ray emitters in the Galactic plane. They are diffuse nebulae that emit nonthermal radiation. Pulsar winds, relativistic magnetized outflows from the central star, shocked in the ambient medium produce a multiwavelength emission from the radio through gamma-rays. Although the leptonic scenario is able to explain most PWNe emission, a hadronic contribution cannot be excluded. A possible hadronic contribution to the high-energy gamma-ray emission inevitably leads to the production of neutrinos. Using 9.5 yr of all-sky IceCube data, we report results from a stacking analysis to search for neutrino emission from 35 PWNe that are high-energy gamma-ray emitters. In the absence of any significant correlation, we set upper limits on the total neutrino emission from those PWNe and constraints on hadronic spectral components.
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18.
  • Ahrens, Maryon, et al. (author)
  • Measurements of the time-dependent cosmic-ray Sun shadow with seven years of IceCube data : Comparison with the Solar cycle and magnetic field models
  • 2021
  • In: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 103:4
  • Journal article (peer-reviewed)abstract
    • Observations of the time-dependent cosmic-ray Sun shadow have been proven as a valuable diagnostic for the assessment of solar magnetic field models. In this paper, seven years of IceCube data are compared to solar activity and solar magnetic field models. A quantitative comparison of solar magnetic field models with IceCube data on the event rate level is performed for the first time. Additionally, a first energy-dependent analysis is presented and compared to recent predictions. We use seven years of IceCube data for the moon and the Sun and compare them to simulations on data rate level. The simulations are performed for the geometrical shadow hypothesis for the moon and the Sun and for a cosmic-ray propagation model governed by the solar magnetic field for the case of the Sun. We find that a linearly decreasing relationship between Sun shadow strength and solar activity is preferred over a constant relationship at the 6.4 sigma level. We test two commonly used models of the coronal magnetic field, both combined with a Parker spiral, by modeling cosmic-ray propagation in the solar magnetic field. Both models predict a weakening of the shadow in times of high solar activity as it is also visible in the data. We find tensions with the data on the order of 3 sigma for both models, assuming only statistical uncertainties. The magnetic field model CSSS fits the data slightly better than the PFSS model. This is generally consistent with what is found previously by the Tibet AS-gamma Experiment; a deviation of the data from the two models is, however, not significant at this point. Regarding the energy dependence of the Sun shadow, we find indications that the shadowing effect increases with energy during times of high solar activity, in agreement with theoretical predictions.
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19.
  • Ahrens, Maryon, et al. (author)
  • Search for Sources of Astrophysical Neutrinos Using Seven Years of IceCube Cascade Events
  • 2019
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 886:1
  • Journal article (peer-reviewed)abstract
    • Low-background searches for astrophysical neutrino sources anywhere in the sky can be performed using cascade events induced by neutrinos of all flavors interacting in IceCube with energies as low as similar to 1 TeV. Previously we showed that, even with just two years of data, the resulting sensitivity to sources in the southern sky is competitive with IceCube and ANTARES analyses using muon tracks induced by charge current muon neutrino interactions-especially if the neutrino emission follows a soft energy spectrum or originates from an extended angular region. Here, we extend that work by adding five more years of data, significantly improving the cascade angular resolution, and including tests for point-like or diffuse Galactic emission to which this data set is particularly well suited. For many of the signal candidates considered, this analysis is the most sensitive of any experiment to date. No significant clustering was observed, and thus many of the resulting constraints are the most stringent to date. In this paper we will describe the improvements introduced in this analysis and discuss our results in the context of other recent work in neutrino astronomy.
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20.
  • Ahrens, Maryon, et al. (author)
  • ANTARES and IceCube Combined Search for Neutrino Point-like and Extended Sources in the Southern Sky
  • 2020
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 892:2
  • Journal article (peer-reviewed)abstract
    • A search for point-like and extended sources of cosmic neutrinos using data collected by the ANTARES and IceCube neutrino telescopes is presented. The data set consists of all the track-like and shower-like events pointing in the direction of the Southern Sky included in the nine-year ANTARES point-source analysis, combined with the throughgoing track-like events used in the seven-year IceCube point-source search. The advantageous field of view of ANTARES and the large size of IceCube are exploited to improve the sensitivity in the Southern Sky by a factor of similar to 2 compared to both individual analyses. In this work, the Southern Sky is scanned for possible excesses of spatial clustering, and the positions of preselected candidate sources are investigated. In addition, special focus is given to the region around the Galactic Center, whereby a dedicated search at the location of SgrA* is performed, and to the location of the supernova remnant RXJ 1713.7-3946. No significant evidence for cosmic neutrino sources is found, and upper limits on the flux from the various searches are presented.
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21.
  • Ahrens, Maryon, et al. (author)
  • Combined search for neutrinos from dark matter self-annihilation in the Galactic Center with ANTARES and IceCube
  • 2020
  • In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 102:8
  • Journal article (peer-reviewed)abstract
    • We present the results of the first combined dark matter search targeting the Galactic Center using the ANTARES and IceCube neutrino telescopes. For dark matter particles with masses from 50 to 1000 GeV, the sensitivities on the self-annihilation cross section set by ANTARES and IceCube are comparable, making this mass range particularly interesting for a joint analysis. Dark matter self-annihilation through the tau(+)tau(-) , mu(+)mu(-) , b (b) over bar, and W+W- channels is considered for both the Navarro-Frenk-White and Burkert halo profiles. In the combination of 2101.6 days of ANTARES data and 1007 days of IceCube data, no excess over the expected background is observed. Limits on the thermally averaged dark matter annihilation cross section are set. These limits present an improvement of up to a factor of 2 in the studied dark matter mass range with respect to the individual limits published by both collaborations. When considering dark matter particles with a mass of 200 GeV annihilating through the tau(+)tau(-)channel, the value obtained for the limit is 7.44 x 10(-24) cm(3) s(-1 )for the Navarro-Frenk-White halo profile. For the purpose of this joint analysis, the model parameters and the likelihood are unified, providing a benchmark for forthcoming dark matter searches performed by neutrino telescopes.
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