Abstracts of Interest
Selected by:
Ryan Burley
Abstract: 1908.08546
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Title:IceCube Search for Galactic Neutrino Sources based on HAWC Observations of the Galactic Plane
(Submitted on 22 Aug 2019)
Abstract: We present a search in IceCube data for neutrino emission from Galactic TeV gamma-ray sources detected by the HAWC gamma-ray observatory. HAWC serves as the excellent instrument to complement IceCube with its energy range extending to very high energies. Assuming that the highest energy photons originate from the decay of pions, rather than from accelerated leptons, the very high energy gamma-rays observed by HAWC are expected to be correlated with neutrinos. Using eight years of IceCube data, we report on two analyses that investigate a possible neutrino--gamma ray correlation. The first is a stacked analysis of identified HAWC point sources and the second is a template method which accounts for the full morphology of HAWC sources, including their measured extension.
Abstract: 1908.08547
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Title:Search for Neutrinos from Populations of Optical Transients
(Submitted on 22 Aug 2019)
Abstract: Since the detection of high-energy cosmic neutrinos at the IceCube Neutrino Observatory in 2013, there has been an on-going search to find the origins of this flux. Despite recent evidence identifying a flaring blazar as a possible neutrino source, the vast majority of the diffuse neutrino flux measured by IceCube remains unexplained. Here, the latest IceCube results testing time-dependent correlation between neutrinos and Tidal Disruption Events (TDEs) are presented, limiting the contribution of jetted and non-jetted TDEs to the diffuse astrophysical neutrino flux to be less than 1.3% and 26% respectively at 90% confidence level. In addition, a dedicated search for neutrinos from the extraordinary transient AT2018cow are presented, and upper limits on the integrated neutrino emission are derived. Expected improvements from new and upcoming time domain optical surveys (such as ZTF and LSST) are also introduced.
Abstract: 1908.08763
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Title:Application of Deep Neural Networks to Event Type Classification in IceCube
(Submitted on 23 Aug 2019)
Abstract: The IceCube Neutrino Observatory is able to measure the all-flavor neutrino flux in the energy range between 100 GeV and several PeV. Due to the different features of the neutrino interactions and the geometry of the detector, all high-level analyses require a selection of suitable events as a first step. However, presently, no algorithm exists that gives a generic prediction of an event's underlying interaction type. One possible solution to this is the use of deep neural networks similar to the ones commonly used for 2D image recognition. The classifier that we present here is based on the modern InceptionResNet architecture and includes multi-task learning in order to broaden the field of application and increase the overall accuracy of the result. We provide a detailed discussion of the network's architecture, examine the performance of the classifier for event type classification and explain possible applications in IceCube.
Abstract: 1908.08765
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Title:Reduction of the Uncertainty in the Atmospheric Neutrino Flux Prediction Using Accurately Measured Atmospheric Muon Flux
(Submitted on 23 Aug 2019)
Abstract: We examine the uncertainty of the calculation of the atmospheric neutrino flux and present a way to reduce it using accurately measured atmospheric muon flux. Considering the difference of the hadronic interaction model and the real one as a variation of hadronic interaction, we find a quantitative estimation method for the error of the atmospheric neutrino flux calculation from the residual of the reconstruction of the atmospheric muon flux observed in a precision experiment, by the study of atmospheric neutrino and muon fluxes response to the variation of hadronic interaction. However, the efficiencty of this method is largely dependent on the observation site of the atmospheric muon flux, as the relation of the error of the atmospheric neutrino flux calculation and the residual of the reconstruction of the atmospheric muon flux is also largely dependent on the muon observation site, especially for the low energy neutrinos. We calculate several observation sites, near Kamioka at sea level, same but 2770m a.s.l.., Hanle India (4500m a.s.l.), and at Balloon altitude ($\sim$ 32km). Then we estimate how stringently can the atmospheric muon reduce the error in the calculation of the atmospheric neutrino flux. We also discuss on the source of error which is difficult to reduce by only the observation of atmospheric muon.
Abstract: 1908.08805
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Title:Search for ultra-high energy photons: observing the preshower effect with gamma-ray telescopes
(Submitted on 23 Aug 2019 (v1), last revised 26 Aug 2019 (this version, v2))
Abstract: Ultra-high energy photons constitute one of the most important pieces of the astroparticle physics problems. Their observation may provide new insight on several phenomena such as supermassive particle annihilation or the GZK effect. Because of the absence of any significant photon identification by a leading experiments such as the Pierre Auger Observatory, we consider a screening phenomenon called preshower effect which could efficiently affect ultra-high energy photon propagation. This effect is a consequence of photon interactions with the geomagnetic field and results in large electromagnetic cascade of particles several thousands kilometers above the atmosphere. This collection of particles, called cosmic-ray ensembles (CRE), may reach the atmosphere and produce the well-known air showers. In this paper we propose to use gamma-ray telescopes to look for air showers induced by CRE. Possible sources of ultra-high energy photons include the GZK effect and Super Heavy Dark Matter particles. Simulations involving the preshower effect and detectors response are performed and properties of these peculiar air showers are investigated. The use of boosted decision trees to obtain the best cosmic-ray ensemble/hadron separation, the aperture and event rate predictions for a few models of photon production are also presented.
Abstract: 1908.08858
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Title:A next-generation ground-based wide field-of-view gamma-ray observatory in the southern hemisphere
(Submitted on 23 Aug 2019)
Abstract: The very-high-energy gamma-ray sky can be surveyed on a daily basis by particle-detector arrays at high (mountain) elevation. In the northern hemisphere the survey recently conducted by the HAWC gamma-ray observatory significantly enriched our knowledge about TeV gamma-ray sources. In this contribution, we will present an overview on the effort to realise a next-generation gamma-ray survey observatory in the southern hemisphere. We will discuss the unique science case for this observatory and how it will be embedded in the multi-messenger and multi-wavelength census of the non-thermal universe. In addition, we will introduce the newly founded international organisation that aims to realise this facility: The Southern Wide field-of-View Gamma-ray Observatory (SWGO) collaboration.
Abstract: 1908.08812
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Title:Synergy between Art and Science: Collaboration at the South Pole
(Submitted on 22 Aug 2019)
Abstract: We present the result of a cross-disciplinary collaboration between Prof. Donald Fortescue of the California College of the Arts in San Francisco and the Dr. Gwenhael de Wasseige of the IceCube Collaboration. The work presented was initiated during Fortescue's US National Science Foundation funded Antarctic Artists and Writers Fellowship at the South Pole in the austral summer of 2016/17. One outcome of this collaboration is the video work Axis Mundi - a timelapse movie captured during 24 hours at the South Pole, combined with a simultaneous sampling of IceCube data transduced into sound. Axis Mundi captures the rotation of the Earth in space, the transient motions of the atmosphere, and the passage of subatomic particles through the polar ice, to provide a means for us to physically engage with these phenomena. We detail how both the timelapse and the transduction of atmospheric muon data have been realized and discuss the benefits of such a collaboration.
Abstract: 1908.08458
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Title:Searches for steady neutrino emission from 3FHLblazars using eight years of IceCube data from theNorthern hemisphere
(Submitted on 22 Aug 2019)
Abstract: Located at the South Pole, the IceCube Neutrino Observatory is the world largest neutrino telescope, instrumenting one cubic kilometre of Antarctic ice at a depth between 1450m to 2450m. In 2013 IceCube reported the first observations of a diffuse astrophysical high-energy neutrino flux. Although the IceCube Collaboration has identified more than 100 high-energy neutrino events, the origin of this neutrino flux is still not known. Blazars, a subclass of Active Galactic Nuclei and one of the most powerful classes of objects in the Universe, have long been considered promising sources of high energy neutrinos. A blazar origin of this high-energy neutrino flux can be examined using stacking methods testing the correlation between IceCube neutrinos and catalogs of hypothesized sources. Here we present the results of a stacking analysis for 1301 blazars from the third catalog of hard \textit{Fermi}-LAT sources (3FHL). The analysis is performed on 8 years of through-going muon data from the Northern Hemisphere, recorded by IceCube between 2009 and 2016. No excess of neutrinos from the blazar position was found and first limits on the neutrino production of these sources will be shown.
Abstract: 1908.08421
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Title:Multi-messenger tests of cosmic-ray acceleration in radiatively inefficient accretion flows
(Submitted on 22 Aug 2019)
Abstract: The cores of active galactic nuclei (AGNs) have been suggested as the sources of IceCube neutrinos, and recent numerical simulations have indicated that hot AGN coronae of Seyfert galaxies and radiatively inefficient accretion flows (RIAFs) of low-luminosity AGNs (LLAGNs) may be promising sites of ion acceleration. We present detailed studies on detection prospects of high-energy multi-messenger emissions from RIAFs in nearby LLAGNs. We construct a model of RIAFs that can reproduce the observational features of the current X-ray observations of nearby LLAGNs. We then calculate the high-energy particle emissions from nearby individual LLAGNs, including MeV gamma rays from thermal electrons, TeV--PeV neutrinos produced by non-thermal protons, and sub-GeV to sub-TeV gamma rays from proton-induced electromagnetic cascades. We find that, although these are beyond the reach of current facilities, proposed future experiments such as e-ASTROGAM and IceCube-Gen2 should be able to detect the MeV gamma rays and the neutrinos, respectively, or else they can place meaningful constraints on the parameter space of the model. On the other hand, the detection of high-energy gamma rays due to the electromagnetic cascades will be challenging with the current and near-future experiments, such as Fermi and Cherenkov Telescope Array. In an accompanying paper, we demonstrate that LLAGNs can be a source of the diffuse soft gamma-ray and TeV--PeV neutrino backgrounds, whereas in the present paper, we focus on the prospects for multi-messenger tests which can be applied to reveal the nature of the high-energy neutrinos and photons from LLAGNs.
Abstract: 1908.08343
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Title:Variational spin-squeezing algorithms on programmable quantum sensors
(Submitted on 22 Aug 2019)
Abstract: Arrays of atoms trapped in optical tweezers combine features of programmable analog quantum simulators with atomic quantum sensors. Here we propose variational quantum algorithms, tailored for tweezer arrays as programmable quantum sensors, capable of generating entangled states on-demand for precision metrology. The scheme is designed to generate metrological enhancement by optimizing it in a feedback loop on the quantum device itself, thus preparing the best entangled states given the available quantum resources. We apply our ideas to generate spin-squeezed states on Sr atom tweezer arrays, where finite-range interactions are generated through Rydberg dressing. The complexity of experimental variational optimization of our quantum circuits is expected to scale favorably with system size. We numerically show our approach to be robust to noise, and surpassing known protocols.
Abstract: 1908.08364
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Title:H.E.S.S. searches for TeV gamma rays associated to high-energy neutrinos
(Submitted on 22 Aug 2019)
Abstract: The detection of an astrophysical flux of high-energy neutrinos by IceCube is a major step forward in the search for the origin of cosmic rays, as this emission is expected to originate in hadronic interactions taking place in or near cosmic-ray accelerators. No neutrino point sources, or significant correlation with known astrophysical objects, have been identified in the IceCube data so far. The hadronic interactions responsible for the neutrino emission should also lead to the production of high-energy gamma rays. The search for neutrino sources can then be performed by studying the spatial and temporal correlations between neutrino events and very high energy (VHE, E > 100 GeV) gamma rays. We report here on the search for VHE gamma-ray emission with the H.E.S.S. imaging air Cherenkov telescopes (IACTs) at the reconstructed position of muon neutrino events detected by IceCube. We will provide an up-to-date summary of the extensive program to perform prompt IACT observations of realtime IceCube neutrino event positions. A recent highlight of this program are the H.E.S.S. observations during the broad multi-wavelength campaign that followed the detection of the neutrino event IceCube-170922A arriving from a direction consistent with the location of a flaring gamma-ray blazar TXS 0506+056 in September 2017. We'll present the H.E.S.S. observations obtained within ~4h hours of the neutrino detection as well as a complementary search for gamma-ray emission at longer timescales and put them into the multi-wavelength and multi-messenger context.
Abstract: 1908.08300
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Title:First search for GeV neutrinos from bright gamma-ray solar flares using the IceCube Neutrino Observatory
(Submitted on 22 Aug 2019)
Abstract: In response to a reported increase in the total neutrino flux in the Homestake experiment in coincidence with solar flares at the end of the eighties, solar neutrino detectors have searched for solar flare signals. Solar flares convert magnetic energy into thermal energy of plasma and kinetic energy of charged particles such as protons. As a consequence of magnetic reconnection, protons are injected downwards from the coronal acceleration region and can interact with dense plasma in the lower solar atmosphere, producing mesons that will subsequently decay into gamma rays and neutrinos at O(MeV-GeV) energies. The main motivation to search for solar flare neutrinos comes from their hadronic origin. As inherent products of high-energy proton collisions with the chromosphere, they are a direct probe of the proton accelerated towards the chromosphere. Using a multi-messenger approach, it is therefore possible to constrain the proton acceleration taking place in the solar flares, including the spectral index of the accelerated flux and its shape. We present the results of the first search for GeV neutrinos emitted during solar flares carried out with the IceCube Neutrino Observatory. We present a new approach which allows us to strongly lower the energy threshold of IceCube, originally designed to detect 10 GeV - PeV neutrinos. We compare the results with theoretical estimates of the corresponding flux.
Abstract: 1908.08299
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Title:Probing neutrino emission at GeV energies from compact binary mergers with IceCube
(Submitted on 22 Aug 2019)
Abstract: The advent of Multi-Messenger Astronomy has allowed for new types of source searches within the neutrino community. We present the results of the first search for GeV astrophysical neutrinos emitted from Compact Binary Mergers, i.e. binary black hole or binary neutron star mergers, detected by the LIGO and Virgo interferometers. We introduce a new approach that lowers the energy threshold of IceCube from roughly 10 GeV to <1 GeV. This method uses an innovative event selection of GeV neutrino events in IceCube and searches for a statistically significant increase in the amount of GeV-like events detected around the Compact Binary Merger time. We compare our results with constraints set by high-energy neutrino searches, and describe the complementarity of these low and high-energy searches.
Abstract: 1908.08248
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Title:Searches for point-like sources of cosmic neutrinos with 11 years of ANTARES data
(Submitted on 22 Aug 2019)
Abstract: The main goal of the ANTARES neutrino telescope is the identification of neutrinos from cosmic accelerators. The good visibility towards the Southern sky for neutrino energies below 100 TeV and the good angular resolution for reconstructed events make the telescope excellent to test for the presence of point-like sources, especially of Galactic origin. The median angular resolution for track-like events (mainly from $\nu_{\mu}$ CC interactions) is $0.4^{\circ}$ while the median angular resolution for contained shower-like events (mainly from $\nu_{e}$ CC and all-flavour NC interactions) is $3^{\circ}$. Recently the ANTARES Collaboration published the result of the search for cosmic point-like neutrino sources using track-like and shower-like events collected during nine years of data taking. In this contribution, an update to this analysis using eleven years of data recorded between early 2007 and the end of 2017, for a total livetime of 3136 days, is presented. Moreover, the results of a search for time and space correlation between the ANTARES events and 54 IceCube tracks and those of the searches for neutrino candidates associated with the IceCube-170922A event or from the direction of the TXS 0506+056 blazar are reported.
Abstract: 1908.08236
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Title:Dark matter searches with the IceCube Upgrade
(Submitted on 22 Aug 2019)
Abstract: Weakly Interacting Massive Particles (WIMPs) are well-motivated candidates for Dark Matter (DM). WIMP models often include self-annihilation into Standard Model particles such as neutrinos which could potentially be detected by the IceCube Neutrino Observatory. Various searches for a dark matter induced signal have been performed with the existing IceCube detector. However, since there is so far no evidence for WIMPs at TeV scales, more attention is brought to DM candidates at GeV masses, for which the IceCube detector is not sensitive due to its energy threshold. The IceCube collaboration is currently preparing the construction of the IceCube Upgrade which is planned to be deployed in the 2022/2023 South Pole summer season. The IceCube Upgrade will consist of 7 new in-ice strings with about 700 additional optical sensors. This dense sensor array inside the IceCube-DeepCore volume will enhance the reconstruction capability of few-GeV neutrinos. We present first studies on the potential improvements of this upgrade on IceCube's sensitivity to Dark Matter annihilating in the Galactic Center.
Abstract: 1908.08139
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Title:Cosmic Ray Spectrum and Composition from PeV to EeV from the IceCube Neutrino Observatory
(Submitted on 21 Aug 2019)
Abstract: The IceCube Neutrino Observatory at the South Pole is a multi-component detector capable of measuring the cosmic ray energy spectrum and composition from PeV to EeV, the energy region typically thought to cover the transition from galactic to extragalactic sources of cosmic rays. The IceTop array at the surface is sensitive to the electromagnetic part of the air shower while the deep in-ice array detects the high-energy (TeV) muonic component of air showers. IceTop's reconstructed shower size parameter, S$_{125}$, is unfolded into a high statistics all-particle energy spectrum. Furthermore, for air showers that pass through both arrays, the in-ice reconstructed muon energy loss information is combined with S$_{125}$ in a machine learning algorithm to simultaneously extract both the all-particle energy spectrum and individual spectra for elemental groups. The all-particle spectra as well as spectra for individual elemental groups are presented.
Abstract: 1908.08060
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Title:A search for IceCube events in the direction of ANITA neutrino candidates
(Submitted on 21 Aug 2019)
Abstract: The Antarctic Impulsive Transient Antenna (ANITA) collaboration has reported a total of three neutrino candidates from the experiment's first three flights. One of these was the lone candidate in a search for Askaryan radio emission, and the others can be interpreted as tau-neutrinos, with important caveats. Among a variety of explanations for these events, they may be produced by astrophysical transients with various characteristic timescales. We test the hypothesis that these events are astrophysical in origin by searching for IceCube counterparts. Using seven years of IceCube data from 2011 through 2018, we search for neutrino point sources using integrated, triggered, and untriggered approaches, and account for the substantial uncertainty in the directional reconstruction of the ANITA events. Due to its large livetime and effective area over many orders of magnitude in energy, IceCube is well suited to test the astrophysical origin of the ANITA events.
Abstract: 1908.07961
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Title:An improved muon track reconstruction for IceCube
(Submitted on 21 Aug 2019)
Abstract: IceCube is a cubic-kilometer Cherenkov telescope operating at the South Pole. One of its main objectives is to detect astrophysical neutrinos and identify their sources. High-energy muon neutrinos are identified through the secondary muons produced via charge current interactions with the ice. The present best-performing directional reconstruction of the muon track is a maximum likelihood method which uses the arrival time distribution of Cherenkov photons registered by the experiment's photomultipliers. A known systematic shortcoming of the prevailing method is to assume a continuous energy loss along the muon track. This contribution discusses a generalized Ansatz where the expected arrival time distribution is parametrized by a stochastic muon energy loss pattern. This more realistic parametrization of the muon energy loss profile leads to an improvement of about 20% to the muon angular resolution of IceCube.
Abstract: 1908.07930
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Title:The lateral distribution function of cosmic-ray induced air showers studied with the HAWC observatory
(Submitted on 21 Aug 2019)
Abstract: The particle lateral distribution function (LDF) of air showers at a given altitude is sensitive to the mass composition and primary energy of cosmic rays. Studies of the LDF are difficult to perform due to experimental effects such as sampling bias, as well as shower-to-shower fluctuations in particle density. The High Altitude Water Cherenkov (HAWC) observatory, a dense air shower array located in central Mexico at 4100 m a.s.l., is well-suited to perform detailed event-by-event studies of the LDF of multi-TeV cosmic-ray showers. The detector is instrumented with 1,200 photomultipliers (PMTs) in close-packed water Cherenkov tanks containing a total of 60 ML of water. We present a study of the LDF of cosmic-ray air showers recorded by HAWC in 2016 with energies between 3 TeV and 300 TeV and zenith angle < 16.7$^{\circ}$. The data are used to determine the optimal parameterization of the LDF at the HAWC site. From here the lateral shower age is obtained and its sensitivity to the cosmic ray mass composition is analyzed.
Abstract: 1908.07717
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Title:Search for very-high-energy photons from Gamma-ray bursts with HAWC
(Submitted on 21 Aug 2019)
Abstract: Detections of very-high-energy (VHE; > 100 GeV) photons from Gamma-ray bursts (GRBs) can provide fundamental information on the involved radiative processes, physical composition of the ejecta and acceleration processes. The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is the best gamma-ray instrument to study transient phenomena over a long period of time from 100 GeV to 100 TeV. Its large field of view and duty cycle (> 95%) allow it to search blindly for sources of GRBs and to follow up on external alerts from satellite instruments, such as Fermi and Swift, searching for their VHE counterpart. We present results from the on-going GRB monitoring program and VHE upper limits of the latest interesting low-redshift and/or powerful bursts in HAWC's field of view: GRB 170206A, GRB 170817A, GRB 180720B and GRB 190114C.
Abstract: 1908.07706
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Full Text: [ PostScript, PDF]
Title:A Search for IceCube Neutrinos from the First 33 Detected Gravitational Wave Events
(Submitted on 21 Aug 2019)
Abstract: The discoveries of high-energy astrophysical neutrinos by IceCube in 2013 and of gravitational waves by LIGO in 2015 have enabled a new era of multi-messenger astronomy. Gravitational waves can identify the merging of compact objects such as neutron stars and black holes. These compact mergers, especially neutron star mergers, are potential neutrino sources. We present an analysis searching for neutrinos from gravitational wave sources reported by the LIGO Virgo Collaboration (LVC). We use a dedicated transient likelihood analysis combining IceCube events with source localizations provided by LVC as spatial priors. We report results for all gravitational wave events from the O1, O2, and O3 observing runs.
Abstract: 1908.07602
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Title:Quest for new physics using astrophysical neutrino flavor in IceCube
(Submitted on 20 Aug 2019 (v1), last revised 22 Aug 2019 (this version, v2))
Abstract: We have detected astrophysical neutrinos in IceCube that can be used to probe astrophysical sources at ultra high scales. Here we report a search for anomalous space time effects using astrophysical neutrino flavor data in IceCube. New effective operators are introduced to drive non-standard neutrino flavor mixing which modify the flavor ratios compared to standard cases. Using the High Energy Starting Events sample (HESE) 7.5-year data for this analysis, we found no evidence of such flavor anomalies. However, we are expecting to set limits from this new approach which goes far beyond any known techniques. Importantly, we achieve the necessary precision to probe new physics using neutrino flavor expected by Planck scale theories.
Abstract: 1908.07582
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Full Text: [ PostScript, PDF]
Title:A Three-dimensional Reconstruction of Cosmic Ray Events in IceCube
(Submitted on 20 Aug 2019)
Abstract: The IceCube Neutrino Observatory at the geographic South Pole consists of two components, a km2 surface array IceTop and a km3 in-ice array between 1.5 and 2.5 km below the surface. Cosmic ray events with primary energy above a few tens of TeV may trigger both the IceTop and in-ice array and leave a three-dimensional footprint of the electromagnetic and muonic components in the extensive air shower. A new reconstruction based on the minimization of a unified likelihood function involving quantities measured by both IceTop and in-ice detectors was developed. This report describes the new reconstruction algorithm and summarizes its performance tested with Monte Carlo events under two different containment conditions. The advantages of the new reconstruction are discussed in comparison with reconstructions that use IceTop or in-ice data separately. Some possible improvements are also summarized.
Abstract: 1908.07439
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Full Text: [ PostScript, PDF]
Title:ANTARES and IceCube combined search for neutrino point-like and extended sources in the Southern Sky
(Submitted on 20 Aug 2019)
Abstract: The ANTARES neutrino telescope, located in the Mediterranean Sea, and the IceCube neutrino observatory, located at the geographic South Pole, both search for cosmic neutrino events with an instantaneous full-sky field of view. The different characteristics of the two telescopes, in particular the larger instrumented volume of IceCube and the better visibility towards the Southern Sky for neutrino energies below 100 TeV of ANTARES, are exploited in a combined search for point-like and extended sources. The sensitivity to neutrino sources located in the Southern Sky is improved by a factor of $\sim$2 compared to individual studies. The data samples used in this analysis correspond to all track-like and shower-like events from the direction of the Southern Sky which were included in the nine-year ANTARES point-source analysis, combined with the through-going track-like events used in the seven-year IceCube point-source search. In this analysis, the Southern Sky is scanned for possible excesses of neutrinos that might indicate the presence of a source, while the coordinates of predefined candidate neutrinos sources are also evaluated in order to limit the penalty of trials. In addition, special focus is given to the region around the Galactic Centre, treated as an extended neutrinos source, and to the location of the supernova remnant RXJ 1713.7-3946. The result of this combined search for galactic and extra-galactic neutrino sources in the Southern Sky is reported here. No significant evidence of cosmic neutrino sources is found and flux upper limits from the various searches are presented.
Abstract: 1908.07300
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Full Text: [ PostScript, PDF]
Title:Combined Search for Neutrinos from Dark Matter Annihilation in the Galactic Centre using ANTARES and IceCube
(Submitted on 20 Aug 2019)
Abstract: The ANTARES and IceCube neutrino telescopes have both searched for neutrinos from dark matter annihilation in the Galactic Centre, putting limits on the thermally-averaged dark matter self-annihilation cross section $\langle \sigma_A \upsilon \rangle$. For WIMP masses above 100 GeV, the most stringent limits were obtained by the ANTARES neutrino telescope, while for lower masses, limits achieved by IceCube are more competitive. The limits obtained by the two detectors are of comparable order of magnitude for WIMP masses going from 50 to 1000 GeV, making this mass range particularly interesting for a combined analysis. In this contribution, we present the limits of the first combined search for dark matter self-annihilation in the centre of the Milky Way using ANTARES and IceCube. The model parameters and the likelihood method were unified, thereby providing a benchmark for future dark matter searches conducted by each collaboration. By combining data of both detectors, we obtained improved limits with respect to the original limits published by the two collaborations.
Abstract: 1908.07255
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Title:Search for dark matter annihilation in the center of the Earth with 8 years of IceCube data
(Submitted on 20 Aug 2019)
Abstract: Dark matter particles in the galactic halo can scatter off particles in celestial bodies such as stars or planets, lose energy and become gravitationally trapped. In this process, an accumulation of dark matter in the center of celestial bodies is expected, for example, at the center of the Earth. If dark matter self-annihilates into Standard Model particles, the end products of these annihilations include neutrinos. The IceCube Neutrino Observatory at the geographic South Pole can detect the resulting flux of neutrinos originating from dark matter annihilation in the center of the Earth. A search for this signal is on-going using 8 years of IceCube data and probing different annihilation channels. Here the sensitivities are presented for this new analysis, showing significant improvements with respect to the previous analyses from IceCube and other experiments.
Abstract: 1908.07249
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Full Text: [ PostScript, PDF]
Title:Eleven Year Search for Supernovae with the IceCube Neutrino Observatory
(Submitted on 20 Aug 2019)
Abstract: The IceCube Neutrino Observatory, which instruments 1$\,$km$^3$ of clear ice at the geographic South Pole, was mainly designed to detect particles with energies in the multi-GeV to PeV range. Due to ice temperatures between $-20^\circ$C to $-43^\circ$C and the low radioactivity of the ice, the dark noise rates of the 5160 photomultiplier tubes forming the IceCube lattice are of order 500 Hz, which is particularly low for 10 inch photomultipliers. Therefore, IceCube can extend its searches to bursts of $\mathcal{O}$(10$\,$MeV) neutrinos lasting several seconds, which are expected to be produced by Galactic core collapse supernovae. By observing a uniform rise in all photomultiplier rates, IceCube can provide a particularly high statistical precision for the neutrino rate from supernovae in the inner part of our Galaxy ($<$ 20 kpc). In this paper, the tools and the method to study potential obscured or failed core collapse supernovae in our Galaxy are presented. The analysis will be based on 3911 days of IceCube data taken between April 17, 2008 and December 31, 2018.
Abstract: 1908.07143
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Title:Low Energy Cosmic Ray Spectrum from 250 TeV to 10 PeV using IceTop
(Submitted on 20 Aug 2019)
Abstract: Using IceTop, the surface component of the IceCube Neutrino Observatory, the all-particle cosmic ray energy spectrum has been determined above a few PeV. The measured energy spectrum leaves a gap of more than a decade in energy to direct measurements by balloon and satellite experiments. In this analysis, we lowered the energy threshold of IceTop to 250 TeV, narrowing the gap between IceTop and direct measurements. In order to collect lower energy events, we implemented a new trigger that uses four pairs of infill stations for which the separation between stations is less than 50 m, compared to 125 m for the main array. The new trigger collects data from the entire array for events with hits on at least one infill pair. The low-energy extension of the all-particle cosmic ray energy spectrum using these IceTop events is measured and is compared with the energy spectrum from HAWC and other experiments. Air shower simulations with two different hadronic interaction models, Sibyll 2.1 and QGSJetII-04, are used in this analysis and an energy spectrum for each model is produced. Both measured energy spectra show a bend around the knee region.
Abstract: 1908.07059
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Full Text: [ PostScript, PDF]
Title:First HAWC Spectra of Galactic Gamma-ray Sources Above 100 TeV and the Implications for Cosmic-ray Acceleration
(Submitted on 19 Aug 2019)
Abstract: We present the first catalogs of the highest-energy (above 56 TeV and 100 TeV) gamma-ray sources seen by the High Altitude Water Cherenkov (HAWC) Observatory. The wide field-of-view of HAWC naturally lends itself to unbiased all-sky surveys and newly developed event-by-event gamma-ray energy reconstruction algorithms have allowed unprecedented energy resolution. The sources presented here are the highest-energy sources ever detected. All are coincident with known lower-energy gamma-ray sources within our Galaxy. These objects may have implications for the sources of Galactic cosmic rays; since Galactic CRs have been observed up to PeV energies, sources accelerating particles to these energies must exist. These sources, called "PeVatrons", would have corresponding hard gamma-ray spectra that extend to high energies without any spectral break or cutoff. We will present measurements of the spectra of these highest-energy gamma-ray sources and discuss if any of them can be identified as PeVatron candidates.
Abstract: 1908.06123
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Title:Measurement of the multi-TeV neutrino cross section with IceCube using Earth absorption
(Submitted on 16 Aug 2019)
Abstract: IceCube detects neutrinos at energies orders of magnitude higher than any neutrinos produced at particle accelerators. Neutrinos are weakly interacting particles but at energies above 30 TeV the Earth becomes opaque to neutrinos. The neutrino cross section is well predicted in the Standard Model. Any unexpected increase in the cross-section could be a sign of beyond the standard model physics. In this analysis IceCube's through-going muon neutrino flux is used to fit for the cross section of neutrino interaction, the through-going high energy neutrinos will be absorbed as they travel through the Earth and a maximum likelihood fit allows for the cross section to be determined as a multiple of the Standard Model prediction. We will review the measurement of the neutrino cross section using 1 year of IceCube data, containing 10,000 events, which was found to be consistent with Standard Model predictions. In this contribution, we present plans for an extension to this analysis using 8 years of IceCube data, approximately 300,000 events. In the extension the cross section will be measure per neutrino energy for both charged and neutral current interactions. This will be the most accurate high-energy muon neutrino cross section measurement available, while also being sensitive to any beyond the Standard Model components.
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