TAROGE-M: Radio Antenna Array on Antarctic High Mountain for Detecting Near-Horizontal Ultra-High Energy Air Showers

Abstract

TAROGE-M is a self-triggered radio antenna array atop the 2700 m high Mt. Melbourne in Antarctica, designed to detect impulsive geomagnetic emission from extensive air showers induced by ultra-high energy (UHE) particles beyond 0.1 EeV, including cosmic rays (CRs), Earth-skimming tau neutrinos, and particularly, the "ANITA anomalous events" (AAEs) from near and below the horizon, which origin remains uncertain and requires more experimental inputs for clarification. The detection concept of TAROGE-M takes advantage of a high altitude with synoptic view toward the horizon as an efficient signal collector, and the radio quietness as well as strong and near vertical geomagnetic field in Antarctica. This approach has a low energy threshold, high duty cycle, and is easy to extend for quickly enlarging statistics. Here we report experimental results from the first TAROGE-M station deployed in 2020, corresponding to $25.3$-days of livetime. The station consists of six receiving antennas operating at 180-450 MHz, and can reconstruct source directions with $\sim 0.3^{\circ }$ angular resolution. To demonstrate its ability to detect UHE air showers, a search for CR signals in the data was conducted, resulting in seven identified events. These events have a mean reconstructed energy of $0.95_{-0.31}^{+0.46}$ EeV and zenith angles between $25^{\circ }-82^{\circ }$, with both distributions agreeing with simulations. The estimated CR flux is also consistent with results of other experiments. The TAROGE-M sensitivity to AAEs is approximated by the tau neutrino exposure with simulations, suggesting comparable sensitivity as ANITA's at $1$ EeV energy with a few station-years of operation. These first results verified the station design and performance in a polar and high-altitude environment, and are promising for further discovery of tau neutrinos and AAEs after an extension in the near future.

41 pages, 23 figures, submitted to JCAP; minor corrections in references; minor modifications in simulation description in section 5 & 6 for clarity

References in corpus (14)

• Radio detection of Cosmic-Ray Air Showers and High-Energy Neutrinos
• A method for high precision reconstruction of air shower Xmax using two-dimensional radio intensity profiles
• Radio detection of air showers with the ARIANNA experiment on the Ross Ice Shelf
• Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers
• A Comprehensive Approach to Tau-Lepton Production by High-Energy Tau Neutrinos Propagating Through Earth
• Depth of shower maximum and mass composition of cosmic rays from 50 PeV to 2 EeV measured with the LOFAR radio telescope
• A Dark Matter Interpretation of the ANITA Anomalous Events
• An Andean Deep-Valley Detector for High-Energy Tau Neutrinos
• Design and Initial Performance of the Prototype for the BEACON Instrument for Detection of Ultrahigh Energy Particles
• Analysis of a Tau Neutrino Origin for the Near-Horizon Air Shower Events Observed by the Fourth Flight of the Antarctic Impulsive Transient Antenna (ANITA)
• Measuring the Polarization Reconstruction Resolution of the ARIANNA Neutrino Detector with Cosmic Rays
• The SLAC T-510 experiment for radio emission from particle showers: detailed simulation study and interpretation
• Trinity's Sensitivity to Isotropic and Point-Source Neutrinos
• Triboelectric Backgrounds to radio-based UHE Neutrino Exeperiments

Cited by in corpus (4)

• Radio Detection of High Energy Neutrinos in Ice
• Radio Detection of ultra-high-energy Cosmic-Ray Air Showers
• Towards the Giant Radio Array for Neutrino Detection (GRAND): the GRANDProto300 and GRAND@Auger prototypes
• Validation of straight-line signal propagation for radio signal of very inclined cosmic ray air showers