Bulletin of the American Physical Society
APS April Meeting 2020
Volume 65, Number 2
Saturday–Tuesday, April 18–21, 2020; Washington D.C.
Session R09: Observational Aspects of Neutrino AstrophysicsLive
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Sponsoring Units: DAP Chair: Marcos Santander, University of Alabama Room: Roosevelt 4 |
Monday, April 20, 2020 1:30PM - 1:42PM Live |
R09.00001: IceCube-HAWC realtime coincidence analysis with sub-threshold data Hugo Ayala Multimessenger astrophysics has become the next step to understand high-energy astrophysical phenomena in the universe. Evidence for the detection of a gamma-ray and neutrino source has been presented for the source TXS 0506+056; however, more detections are needed. We present preliminary results on the generation of real-time ($\sim 6$ hours) TeV gamma-ray and neutrino multimessenger transient alerts with subthreshold data from the HAWC gamma-ray and IceCube neutrino observatories via the Astrophysical Multimessenger Observatory Network (AMON). The analysis is based on a likelihood ratio framework, yielding real-time AMON coincidence alerts for HAWC "hot spots" and IceCube neutrinos of potential astrophysical origin. These alerts are being distributed to AMON follow-up partners with a median anticipated delay of six hours due to the timescale of the search with HAWC, which corresponds to a full transit in its field of view. These coincident alerts have an angular resolution of $\sim 0.2^{\circ}$ and are well-suited for deep electromagnetic follow-up observations. [Preview Abstract] |
Monday, April 20, 2020 1:42PM - 1:54PM Live |
R09.00002: Constraining Galaxy Clusters as Steady Sources of Cosmic Neutrinos with IceCube Mehr Un Nisa, Andrew Ludwig, Srinivasan Raghunathan, Marcos Santander The origin of the high-energy astrophysical neutrino flux observed by the IceCube Neutrino Observatory is an open problem, directly linked to the search for the sources of the highest energy cosmic rays. One promising class of candidate sources are clusters of galaxies. Cosmic rays accelerated in central AGN activity can be confined by turbulent magnetic fields in galaxy clusters. These cosmic rays can then interact with the intra-cluster medium to produce a steady flux of neutrinos and gamma rays. Such models of neutrino emission can be tested by searching for correlations between the directions of neutrino events and galaxy clusters hosting AGN. Using a sample of over 1500 X-ray bright clusters, we present the first search for associated neutrino signals in 10 years of IceCube data, and discuss the implications for specific models of cosmic neutrino emission. [Preview Abstract] |
Monday, April 20, 2020 1:54PM - 2:06PM Live |
R09.00003: Simulation Study of Radio Signals from Cosmic Ray Air Showers for an Antenna Array at IceTop Abdul Rehman, Frank Schroeder Finding sources of high-energy cosmic rays (CRs) is about a century-old question. However, the mass composition of CRs contains important clues that can lead to the answers. At high energies, the mass composition of CRs is only inferred from the detection of mass-sensitive parameters of extensive air shower (EAS), like the depth into the atmosphere at which the shower contains the most number of particles ($X_{\mathrm{max}}$). Radio waves are emitted due to the time-varying distributions of charged particles (mostly electrons and positrons) in EASs. Most of the emission occurs from the region around $X_{\mathrm{max}}$ which makes the radio signal on ground sensitive to $X_{\mathrm{max}}$. To facilitate the computationally expensive methods for $X_{\mathrm{max}}$ reconstruction, we investigate an interpolation method. We use COREAS to simulate the radio signal at fixed grid positions and then use an interpolation to shift the core position at various locations. This method will be applied to the planned enhancement of the IceCube surface array (IceTop) at the South Pole. The IceTop upgrade with scintillators and radio antennas will improve its sensitivity and will open new science cases like the search for PeV gammas from the Galactic Center. [Preview Abstract] |
Monday, April 20, 2020 2:06PM - 2:18PM Live |
R09.00004: Constraints on astrophysical interpretations of anomalous ANITA events with IceCube Alex Pizzuto Recently, the ANITA collaboration reported the detection of several events potentially consistent with neutrino interpretations. Two of these events are from upward-going extensive air showers, compatible with the signature of tau decay from an ultra-high energy tau neutrino interaction. A third, although consistent with background expectations, was detected in a search for Askaryan radiation. The steep emergence angles of the first two events is in tension with limits on isotropic cosmogenic neutrino fluxes. Here, we consider the hypothesis that these events are from neutrinos produced in the vicinity of cosmic accelerators, and search for coincident neutrinos with IceCube. In the absence of a significant detection, we set upper limits on neutrino fluxes from potential point sources. As any ultra-high-energy tau neutrino flux traversing the Earth should be accompanied by neutrinos in the TeV-PeV range, this non-observation severely constrains any standard model astrophysical interpretation of the ANITA events, regardless of the assumptions on intrinsic spectrum or time profile. [Preview Abstract] |
Monday, April 20, 2020 2:18PM - 2:30PM Live |
R09.00005: Cosmic Ray Candidates in the Askaryan Radio Array and Implications for Neutrino Detection Amy Connolly The Askaryan Radio Array (ARA) is an array of antennas deployed at 200m depth near South Pole, aiming to detect ultra-high energy neutrinos via the radio Askaryan technique. While neutrino detection is ARA’s primary aim, measurement of cosmic rays via geomagnetic emission, which has been well established by other radio arrays at the surface, would provide a unique opportunity for calibration of the ARA detector as well as simulations of the instrument. ARA would observe cosmic rays from a unique vantage point in the deep ice, giving us the additional opportunity to observe a characteristic radio signature expected from cosmic ray showers that may penetrate the ice. We report on the first set of candidate cosmic rays observed by ARA, identified incidentally in data analysis leading to ARA’s most recent search for neutrinos in four years of data from two stations. I will also discuss implications for current and future radio arrays in deep ice. [Preview Abstract] |
Monday, April 20, 2020 2:30PM - 2:42PM Live |
R09.00006: W-Boson and Trident Production in IceCube and IceCube-Gen2: Cross Sections and Detectability Bei Zhou, John Beacom Detecting TeV–PeV cosmic neutrinos provides crucial tests of neutrino physics and astrophysics. The statistics of IceCube and the larger proposed IceCube-Gen2 demand calculations of neutrino-nucleus interactions subdominant to deep-inelastic scattering, which is mediated by weak-boson couplings to nuclei. The largest such interactions are W-boson and trident production, which are mediated instead through photon couplings to nuclei. We study their phenomenological consequences. We find that: (1) These interactions are dominated by the production of on-shell W-bosons, which carry most of the neutrino energy, (2) The cross section on water/iron can be as large as 7.5%/14% that of charged-current deep-inelastic scattering, much larger than the quoted uncertainty on the latter, (3) Attenuation in Earth is increased by as much as 15%, (4) W-boson production on nuclei exceeds that through the Glashow resonance on electrons by a factor of ' 20 for the best-fit IceCube spectrum, (5) The primary signals are showers that will significantly affect the detection rate in IceCube-Gen2; a small fraction of events give unique signatures that may be detected sooner. (https://arxiv.org/abs/1910.08090 , https://arxiv.org/abs/1910.10720) [Preview Abstract] |
Monday, April 20, 2020 2:42PM - 2:54PM Live |
R09.00007: The search for astrophysical neutrinos from gravitational wave sources in real time with IceCube Justin Vandenbroucke, Raamis Hussain, Alex Pizzuto An electromagnetic counterpart was identified for the first binary neutron star merger detected in gravitational waves (GW 170817) , and a gamma-ray blazar (TXS 0506+056) was identified in coincidence with astrophysical neutrinos. The search is on for the third leg of the multi-messenger triangle: a possible neutrino counterpart to gravitational waves. The IceCube Neutrino Observatory responds rapidly to LIGO/Virgo Open Public Alerts by searching for neutrinos coincident in time and direction with gravitational wave alerts. Detection of a neutrino in coincidence with a gravitational wave source would revolutionize our understanding of both gravitational wave progenitors and astrophysical neutrinos. Doing so in real time would furthermore provide a localization region orders of magnitude smaller than typical gravitational wave regions, in order to quickly search for electromagnetic counterparts. We report results from LIGO/Virgo observing runs O1 and O2 as well as real-time results from O3 to date. [Preview Abstract] |
Monday, April 20, 2020 2:54PM - 3:06PM Live |
R09.00008: Machine Learning in Cosmic Ray Reconstruction with IceCube Roy Wood, Frank McNally, Tyler Sledge Deep neural networks can display increased performance when trained on low-level data, as opposed to high-level physics parameters. We present a test of the effectiveness of this approach as applied to cosmic ray reconstruction. IceTop, the surface component of the IceCube Neutrino Observatory, consists of 81 stations that detect air showers produced by cosmic ray interactions with the atmosphere. An accurate energy estimator for IceTop is essential for studying the nature of the cosmic ray spectrum around the knee (300 TeV - 1 EeV). Using over 400,000 simulated events, an array of convolutional deep neural networks (CNNs) was trained to reconstruct the energy of a cosmic ray primary based on the charges and arrival times detected at the surface. Preliminary results show that these CNN models can deliver an energy resolution better than 10{\%}. This result is consistent with independent energy reconstructions used by IceCube, and indicates the promise of a deep-learning approach. [Preview Abstract] |
Monday, April 20, 2020 3:06PM - 3:18PM Not Participating |
R09.00009: Simulation Study for Radio Measurement of Cosmic Ray Air Showers at the South Pole. Ek Narayan Paudel, Frank Schroeder Radio detection of air showers has developed as an effective technique to study very high energy cosmic rays ($\sim$ 100 PeV). We plan to install a surface array of radio antennas and scintillators as an addition to IceTop, a 1 km$^{2}$ air shower array at the South Pole. This extension will allow an estimation of the mass composition, energy and arrival direction of very high energy cosmic rays. Two significant components of radio emission from air showers are geomagnetic emission and Askaryan emission. The geomagnetic emission is linearly polarized in the direction of the Lorentz force of the Earth's magnetic field while the less prominent Askaryan emission produced by a net charge excess in the shower front is radially polarized. The combined effect of these two creates an asymmetry in the radio signal. In this talk, we are presenting our study of the relative polarization of these two components at the IceTop location using CORSIKA/CoREAS simulations. [Preview Abstract] |
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