Observation of Broadband In-ice Radiation from Impacting High-Energy Cosmic Rays
We present the first experimental evidence for in-ice radiofrequency emission from high-energy particle cascades developing in the Antarctic ice sheet. In 208 days of data recorded with the phased-array trigger of the Askaryan Radio Array, we detect 13 events with impulsive radiofrequency pulses originating from below the ice surface. Considering only the arrival angles and timing properties, this rate is inconsistent with an a-posteriori background expectation for thermal noise events and on-surface events at the level of $3.5\,\sigma$, which rises to $5.1\,\sigma$ when additionally considering impulsivity. The observed event geometry, event rate, signal shape, spectral content, and electric field polarization are consistent with Askaryan radiation from cosmic ray air shower cores impacting the ice sheet. For the brightest events, the angular radiation pattern independently favors an extended cascade-like emitter over a pointlike source.
Authors
- M.A. DuVernois
- A. Novikov
- K.D. Hoffman
- E. Oberla
- K. D. de Vries (ORCID: https://orcid.org/0000-0002-9842-4068)
- R. Young
- T.C. Liu
- J. Hanson (ORCID: https://orcid.org/0000-0003-4055-4553)
- K. Hughes (ORCID: https://orcid.org/0000-0002-4551-9581)
- E. Friedman
- Yijie Pan
- W. Luszczak
- A. Machtay
- N. Harty
- R. J. Nichol (ORCID: https://orcid.org/0000-0003-0557-0443)
- Uzair Abdul Latif (ORCID: https://orcid.org/0000-0002-7609-1266)
- R. Debolt
- A. C. Cummings (ORCID: https://orcid.org/0000-0002-3840-7696)
- L. Cremonesi (ORCID: https://orcid.org/0000-0003-0711-1056)
- Shi Su (ORCID: https://orcid.org/0000-0003-2682-4262)
- Simon De Kockere (ORCID: https://orcid.org/0000-0001-6724-012X)
- Cosmin Deaconu (ORCID: https://orcid.org/0000-0002-4953-6397)
- K. Couberly (ORCID: https://orcid.org/0000-0001-5311-3648)
- A. G. Vieregg (ORCID: https://orcid.org/0000-0002-4528-9886)
- M.-Z. Wang
- Brian Clark (ORCID: https://orcid.org/0000-0003-4089-2245)
- Cheng‐Yu Kuo (ORCID: https://orcid.org/0000-0001-6211-5581)
- A. Nozdrina (ORCID: https://orcid.org/0000-0002-0594-089X)
- C.H. Liu
- P. Chen
- K.-C. Kim
- K. Kurusu
- Nisha B. Alden (ORCID: https://orcid.org/0000-0002-8128-7714)
- A. Ishihara
- Marco Stein Muzio (ORCID: https://orcid.org/0000-0003-4615-5529)
- Stephanie Wissel (ORCID: https://orcid.org/0000-0003-0569-6978)
- A. Connolly
- James D. Roth (ORCID: https://orcid.org/0000-0002-0296-2786)
- D.Z. Besson
- P. J. Windischhofer (ORCID: https://orcid.org/0000-0001-5038-1399)
- M. Huang
- J. J. Beatty (ORCID: https://orcid.org/0000-0003-0481-4952)
- P. Allison
- Y.C. Chen (ORCID: https://orcid.org/0009-0003-8899-8003)
- N. Punsuebsay
- D. Seckel
- Ilya Kravchenko (ORCID: https://orcid.org/0000-0003-0068-0395)
- Chintamani Pai (ORCID: https://orcid.org/0000-0001-8028-6384)
- J. Touart
- Mohammad Ful Hossain Seikh (ORCID: https://orcid.org/0000-0002-4464-7354)
- M.-C. Kim
- Simon Chiche (ORCID: https://orcid.org/0000-0002-2853-5862)
- J.L. Kelley
- A. Salcedo-Gomez (ORCID: https://orcid.org/0000-0002-2931-6602)
- J. Torres (ORCID: https://orcid.org/0000-0003-4385-6127)
- Chao Xie (ORCID: https://orcid.org/0000-0002-6928-5521)
- Y.-C. Chen (ORCID: https://orcid.org/0009-0004-8328-6469)
- S.-H. Wang
- A. Karle
- C. Pfendner
- P. Giri (ORCID: https://orcid.org/0009-0004-0210-9373)
- P. Dasgupta (ORCID: https://orcid.org/0000-0002-9559-4803)
- A. Bishop
- S. Ali (ORCID: https://orcid.org/0000-0001-5216-3133)
- S. Toscano
- K. Mase
- S. Yoshida
- Y.-S. Shiao
- R. Gaior
- S. Archambault
- J. Flaherty
- Ryan Krebs (ORCID: https://orcid.org/0009-0001-9758-9055)
- J. Nam
- N. van Eijndhoven (ORCID: https://orcid.org/0000-0001-5558-3328)
- M. Vilarino Fostier
Publication Details
- Published
- 2025-09-24
- DOI
- https://doi.org/10.22323/1.501.1213
- Primary Topic
- Astrophysics and Cosmic Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Alfred P. Sloan Foundation
- Research Corporation for Science Advancement
- University of Chicago
- Leidos
- Leverhulme Trust
- National Science Council
- Fonds De La Recherche Scientifique - FNRS
- Fonds Wetenschappelijk Onderzoek
- Office of Polar Programs
- Office of Experimental Program to Stimulate Competitive Research