Bulletin of the American Physical Society
APS April Meeting 2023
Volume 68, Number 6
Minneapolis, Minnesota (Apr 15-18)
Virtual (Apr 24-26); Time Zone: Central Time
Session U13: Cosmic Rays |
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Sponsoring Units: DAP Chair: John Krizmanic, NASA Goddard Space Flight Center Room: Marquette IV - 2nd Floor |
Tuesday, April 18, 2023 1:30PM - 1:42PM |
U13.00001: Have we found the counterpart signal of the Fermi bubbles at the cosmic-ray positrons? Ilias Cholis, Iason Krommydas The inner galaxy has hosted cosmic-ray burst events including those responsible for the gamma-ray extit{Fermi} bubbles and the extit{eROSITA} bubbles in X-rays. In this work, we study the extit{AMS-02} positron fraction and find three features around 12, 21 and 48 GeV of which the lowest energy has a 1.4 to 4.9-$sigma$ significance, depending on astrophysical background assumptions. Using background simulations that explain the cosmic-ray positron fraction, positron flux and electron plus positron flux, by primary, secondary cosmic rays and cosmic rays from local pulsars, we test these spectral features as originating from electron/positron burst events from the inner galaxy. We find the 12 GeV feature, to be explained by an event of age $ au simeq 3 - 10$ Myr; in agreement with the proposed age of the extit{Fermi} bubbles. Furthermore, the energy in cosmic-ray electrons and positrons propagating along the galactic disk and not within the extit{Fermi} bubbles volume, is estimated to be $10^{51.5}-10^{57.5}$ ergs, or $O(10^{-4}) -O(1)$ the cosmic-ray energy causing the extit{Fermi} bubbles. We advocate that these positron fraction features, are the counterpart signals of the extit{Fermi} bubbles, or of substructures in them, or of the extit{eROSITA} bubbles. |
Tuesday, April 18, 2023 1:42PM - 1:54PM |
U13.00002: The Snowmass Ultra-High-Energy Cosmic Ray White Paper Eric W Mayotte This talk will give an overview of the key findings and recommendations of the White Paper, Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers, prepared for the Snowmass process. The paper starts with an overview of the recent progress and open questions on ultra-high-energy cosmic rays (UHECRs), with energies greater than 100 PeV, through the lenses of particle physics and astrophysics. It then moves to frame the future potential of the field over the next 10 years, highlighting promising analysis avenues for approaching the community's long-standing goals. Finally, it lays out a 20-year road-map for UHECR science, providing key recommendations on what to consider when funding and building the next generation of UHECR observatories. |
Tuesday, April 18, 2023 1:54PM - 2:06PM |
U13.00003: CNN-based Approach for Cleaning and Identifying Radio Signals Emitted by Cosmic-Ray Air Shower. Abdul Rehman, Alan Coleman, Frank G Schroeder Cosmic rays with high energies produce extensive air showers when they enter Earth's atmosphere. The charged shower particles, mostly electrons and positrons, are deflected by the Earth's magnetic field and produce radio emission. Studying this radio emission can reveal the properties, such as energy and direction, of the initial cosmic-rays. However, radio detection is often impaired by interference, such as human-made radio frequency noise and continuous Galactic background noise. In this study, we present a machine learning method based on a convolutional neural network (CNN) for the classification and reduction of background noise in radio signals. The CNNs are trained and evaluated using simulated radio signals from Monte Carlo simulations of EAS events and measured background noise from a prototype station of IceCube's surface enhancement at the South Pole. Our study shows that the use of CNNs can significantly enhance the accuracy of the arrival time and amplitude of air-shower radio pulses, which will subsequently result in a more precise reconstruction of the properties of cosmic rays. |
Tuesday, April 18, 2023 2:06PM - 2:18PM |
U13.00004: Mass Sensitive Observables of Simulated Cosmic Ray Air Showers Benjamin Flaggs, Alan Coleman, Frank G Schroeder Interactions between high-energy cosmic rays, which are charged particles of astrophysical origin, and atmospheric nuclei produce extensive air showers, cascades of secondary particles and electromagnetic radiation, measurable at ground. Specific air shower observables, such as the depth of shower maximum and relative size of the air-shower muonic component, are sensitive to the mass of the primary cosmic ray particle and therefore provide an avenue for cosmic ray mass composition analyses. The separation power between proton, helium, oxygen, and iron cosmic rays was studied using exact knowledge of mass sensitive air shower observables determined from CORSIKA simulations at the sites of the IceCube Neutrino Observatory at the South Pole and the Pierre Auger Observatory in Argentina. Separation power between primaries was determined from a Fisher linear discriminant analysis where dependencies upon both energy and zenith angle were investigated. Combined knowledge of all studied mass sensitive observables yield promising mass separation power. This motivates equipping the next generation of air-shower arrays with multiple detection techniques for the simultaneous measurement of these shower observables. |
Tuesday, April 18, 2023 2:18PM - 2:30PM |
U13.00005: Results of the CALET Ultra-Heavy Cosmic-Ray Analysis Wolfgang Zober, Brian F Rauch The Calorimetric Electron Telescope (CALET), launched to the International Space Station in August 2015 and has been in continuous operation since, measures cosmic-ray (CR) electrons, nuclei, and gamma rays. CALET, with its 27 radiation length deep Total Absorption Calorimeter (TASC), measures particle energy, allowing for the determination of spectra and secondary to primary ratios of the more abundant CR nuclei through 28Ni, while the main charge detector (CHD) can measure Ultra-Heavy (UH) CR nuclei through 40Zr. By using the special high duty cycle (~90%) UH trigger with a screen that requires UH trigger events to pass through the TASC, we can leverage energy information into our charge determination. While this reduces the total number of analyzed events, the improved charge determination and long duration of the CALET mission provides sufficient peak resolution. Here we present the results of 7 years of observation of the abundances of elements from Z=10 to Z=40 relative to 26Fe and compare our results to previous measurements from ACE-CRIS, SuperTIGER, and HEAO-3. |
Tuesday, April 18, 2023 2:30PM - 2:42PM |
U13.00006: Auger@TA: Deploying an independent Pierre Auger Observatory SD array at the Telescope Array Project Sonja Mayotte The Pierre Auger Observatory and the Telescope Array (TA) are the two largest ultra-high-energy cosmic ray observatories in the world. They operate in the Southern and Northern hemispheres, respectively, at similar latitudes, but with different surface detector (SD) designs. This difference in detector design changes their sensitivity to the various components of extensive air showers. The over-arching goal of the Auger@TA working group is to cross-calibrate the SD arrays of the two observatories via a self-triggering micro-Auger-array inside the TA array, in order to identify or rule out systematic causes for the apparent differences in the flux measured at Auger and TA. |
Tuesday, April 18, 2023 2:42PM - 2:54PM |
U13.00007: Towards a New IceTop Trigger for Inclined Cosmic Rays Ek Narayan Paudel, Serap Tilav, Frank G Schroeder IceTop, the surface component of IceCube Neutrino Observatory at the South Pole, is a cosmic-ray air shower detector comprised of an array of ice-Cherenkov tanks. An enhancement of the surface array is planned to recover the sensitivity lost by snow accumulation over the years. Part of that enhancement are radio antenna, which will increase the measurement accuracy of the electromagnetic component of air showers and are particularly sensitive to inclined showers. Next to increasing the sky coverage and total statistics for other studies such as the measurement of cosmic-ray anisotropy and of the cosmic-ray mass composition, this is one motivation to lower the trigger threshold of IceTop. For these reasons, we have studied a potential new trigger for IceTop which is optimized for inclined shower using CORSIKA simulation as well as periodic readouts of the full IceTop array. In this talk, we will present our plans and progress on the development of this new trigger. |
Tuesday, April 18, 2023 2:54PM - 3:06PM |
U13.00008: The IceAct Cherenkov telescopes at the IceCube Neutrino Observatory Larissa Paul, Karen G Andeen Since 2019 two Imaging Air Cherenkov Telescopes, called IceAct, measure the electro-magnetic component of air showers in the atmosphere above the IceCube Neutrino Observatory. This adds to the existing detectors IceTop and IceCube which are measuring the footprint of cosmic ray induced air showers on the surface and the high energy muonic component at a depth of more than 1.5km. The three independent measurements of the air shower parameters allow for event-by-event measurement of the cosmic ray composition and crosschecks between the detectors. |
Tuesday, April 18, 2023 3:06PM - 3:18PM |
U13.00009: Search for High Energy Photons with the IceAct Telescopes at the Icecube Neutrino Observatory Logan Molchany, Matthias Plum The IceCube Neutrino Observatrory, located at the South Pole, is a multi-component detector array capable of observing astro-particles on the TeV to EeV scale. It consists of both a one square kilometer surface array called IceTop and one cubic kilometer deep in-ice component called IceCube. Since 2019 additionally two Imaging Air Cherenkov Telescopes, called IceAct, were added to measure the electro-magnetic component of air showers in the atmosphere above the IceCube detector. |
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