Scaler Rates from the Pierre Auger Observatory: A New Proxy of Solar Activity
Abstract The modulation of low-energy galactic cosmic rays reflects interplanetary magnetic field variations and can provide useful information on solar activity. An array of ground-surface detectors can reveal the secondary particles, which originate from the interaction of cosmic rays with the atmosphere. In this work, we present an investigation of the low-threshold rate (scaler) time series recorded in 16 yr of operation by the Pierre Auger Observatory surface detectors in Malargüe, Argentina. Through an advanced spectral analysis, we detected highly statistically significant variations in the time series with periods ranging from the decadal to the daily scale. We investigate their origin, revealing a direct connection with solar variability. Thanks to their intrinsic very low noise level, the Auger scalers allow a thorough and detailed investigation of the galactic cosmic-ray flux variations in the heliosphere at different timescales and can, therefore, be considered a new proxy of solar variability.
Authors
- Belén Andrada
- M. Scornavacche
- A. Filipčič
- T. Paulsen
- O. Deligny
- M. Straub
- Bruno L. Lago (ORCID: https://orcid.org/0000-0001-9672-0499)
- L. Caccianiga
- S. Petrera (ORCID: https://orcid.org/0000-0002-6029-1255)
- K.-H. Kampert
- M. Palatka
- Varada Varma Kizakke Covilakam (ORCID: https://orcid.org/0000-0001-5278-3172)
- T. Pierog (ORCID: https://orcid.org/0000-0002-7472-8710)
- S. Michal
- A. Segreto
- V. Rizi
- Carmina Pérez Bertolli (ORCID: https://orcid.org/0000-0002-9790-5732)
- A. Saftoiu
- R. M. de Almeida (ORCID: https://orcid.org/0000-0003-3104-2724)
- Salvatore Mancuso (ORCID: https://orcid.org/0000-0002-9874-2234)
- Frank Schröder (ORCID: https://orcid.org/0000-0001-8495-7210)
- A. C. Fauth (ORCID: https://orcid.org/0000-0001-7239-0288)
- J. Ebr
- C. Watanabe
- Enrique Varela (ORCID: https://orcid.org/0000-0003-0715-7513)
- L. Anchordoqui
- Shigeru Negi (ORCID: https://orcid.org/0000-0002-3526-4140)
- M. Saharan
- Lukáš Vaclavek (ORCID: https://orcid.org/0000-0002-0910-3415)
- A. Novikov
- A. Nucita
- Jill Meinert
- B. R. Dawson
- G. Parente (ORCID: https://orcid.org/0000-0003-2847-0461)
- F. M. Mariani (ORCID: https://orcid.org/0000-0002-1683-1162)
- Mohamed Emam (ORCID: https://orcid.org/0000-0002-0949-5092)
- A. Fernandes (ORCID: https://orcid.org/0009-0000-3687-9182)
- M. Roth (ORCID: https://orcid.org/0000-0003-1281-4477)
- I. Lhenry-Yvon
- I. Allekotte
- Gonzalo Rodriguez Fernandez (ORCID: https://orcid.org/0000-0002-4683-230X)
- Adriel Bartz Mocellin
- G. Consolati
- N. González
- Berenika Čermáková
- S. J. de Jong (ORCID: https://orcid.org/0000-0002-3120-3367)
- F. Campuzano (ORCID: https://orcid.org/0000-0001-7172-3095)
- S. U. Shivashankara
- J. Pallotta
- K. Daumiller (ORCID: https://orcid.org/0000-0002-0527-4823)
- M. Gottowik
- L. Nellen (ORCID: https://orcid.org/0000-0003-1059-8731)
- S. Mayotte
- R. Colalillo
- M. Kleifges
- S. Querchfeld
- A. Letessier-Selvon
- H. O. Klages
- L. Östman
- Katarína Simkova (ORCID: https://orcid.org/0000-0003-2363-9846)
- A. Fuster
- R. Caruso (ORCID: https://orcid.org/0000-0003-1622-8731)
- F. Sarazin (ORCID: https://orcid.org/0000-0001-5614-1986)
- Luis A. Núñez
- Fernando Gollan (ORCID: https://orcid.org/0000-0002-0495-2768)
- M. Cristinziani (ORCID: https://orcid.org/0000-0003-3893-9171)
- Z. Szadkowski
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- Martin Weitz (ORCID: https://orcid.org/0000-0002-4236-318X)
- F. Barbato
- M. Conte
- T. Huege
- L. Miramonti (ORCID: https://orcid.org/0000-0002-2808-5363)
- F. Simon (ORCID: https://orcid.org/0000-0002-5978-0289)
- A. G. Mariazzi (ORCID: https://orcid.org/0000-0002-9876-2470)
- Benjamin Flaggs (ORCID: https://orcid.org/0000-0002-5549-1869)
- G.P. Guedes (ORCID: https://orcid.org/0000-0002-9160-4832)
- M. E. Bertaina
- A. D. Supanitsky (ORCID: https://orcid.org/0000-0002-6942-6216)
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- Miguel A. Martins (ORCID: https://orcid.org/0000-0002-7294-6204)
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- M. Erdmann (ORCID: https://orcid.org/0000-0002-1653-1303)
- Jarosław Stasielak (ORCID: https://orcid.org/0000-0002-9284-7000)
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- J. Řídký (ORCID: https://orcid.org/0000-0001-6697-1393)
- B. Keilhauer (ORCID: https://orcid.org/0000-0003-4494-1155)
- R. W. Clay (ORCID: https://orcid.org/0000-0002-9040-9648)
- Diego Correia dos Santos (ORCID: https://orcid.org/0000-0001-8243-6710)
- S. Buitink
- Vincent Pelgrims (ORCID: https://orcid.org/0000-0002-5053-3847)
- Chloé Gaudu (ORCID: https://orcid.org/0000-0002-2803-4873)
- Yago Lema-Capeans
- Carmen Merx
- Mohsen Pourmohammad Shahvar
- Lukas Gülzow (ORCID: https://orcid.org/0009-0001-0620-3525)
- S. Strähnz
- S. Cabana-Freire
- A. Cermenati
- N. Denner (ORCID: https://orcid.org/0009-0007-3527-0018)
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- João Vítor Reginatto Akim (ORCID: https://orcid.org/0000-0001-8179-9747)
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- Tim Fehler
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- Alan Watson (ORCID: https://orcid.org/0000-0002-3727-6786)
- Luiz Augusto Pereira (ORCID: https://orcid.org/0000-0002-3263-3203)
- Jose Sanabria Gomez (ORCID: https://orcid.org/0000-0002-4217-3212)
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- Marcus Niechciol (ORCID: https://orcid.org/0000-0001-6823-8056)
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- Igor Vaiman (ORCID: https://orcid.org/0000-0002-8255-3631)
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- Juan Manuel González
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- Pavel Horváth (ORCID: https://orcid.org/0000-0002-6710-5339)
- Nataliia Borodai (ORCID: https://orcid.org/0000-0003-1864-937X)
- Kévin Almeida Cheminant (ORCID: https://orcid.org/0000-0001-6352-5339)
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- P. G. Brichetto Orchera
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- J. R. Hörandel
- M. A. Leigui de Oliveira
- P. Savina
- M. Cerda
- T. Schulz
- L. Valore
- E. E. Pereira Martins
- W. M. Namasaka
- L. Nožka
- P. Hamal (ORCID: https://orcid.org/0000-0003-3139-7234)
- J. Vink
- P. Hansen
- Ioana Codrina Mariş (ORCID: https://orcid.org/0000-0002-5771-1124)
- F. Salamida
- M. Tueros (ORCID: https://orcid.org/0000-0002-6632-0440)
- A. Bueno (ORCID: https://orcid.org/0000-0002-1930-3576)
- T. Suomijärvi
- M. Risse
- R. Engel
- D. Wittkowski
- J. F. Valdés Galicia
- F. L. Briechle
- E. Roulet
- C. Aramo
- O. Scholten
- A. Insolia
- F. Gobbi
- I. Epicoco
- P. Abreu
- Max Büsken
- A. Abdul Halim
- Gualberto Avila
- Marta Bianciotto
- P. Filip (ORCID: https://orcid.org/0000-0003-4896-7053)
- N. Kunka
- C. S. Cruz Sanchez
- L. Lopes (ORCID: https://orcid.org/0000-0001-8571-0033)
- M. Schimp (ORCID: https://orcid.org/0000-0001-6407-7187)
- Jörg R. Hörandel
- J. C. D’Olivo
- B. B. Yue (ORCID: https://orcid.org/0000-0001-6861-3864)
- S. Andringa
- J. Pȩkala
- M. R. Hampel
- M. Platino
- M. Aglietta
- A. Condorelli
- S. Verpoest
- D. Ravignani
- Subhash Chandra Panja
- D. Veberič
- E. Guido
- Miroslav Hrabovský
- L. Perrone
- J. C. Arteaga Velázquez
- E. Arnone
- S. Sehgal
- Vlastimil Jílek (ORCID: https://orcid.org/0000-0001-5774-7285)
- V. Vašíčková
- Khoa Nguyen
- P. Trávnı́ček (ORCID: https://orcid.org/0000-0002-1655-9584)
- A. Menshikov
- D. Melo
- A. Etchegoyen
- J. Blazek
- L. Apollonio
- D. Martello
- G. Medina-Tanco
- E. Santos (ORCID: https://orcid.org/0000-0001-6519-8052)
- E. Rodriguez
- F. Krieger
- R. Squartini
- A. Weindl
- M. Gómez Berisso
- B. Fick
- V. Novotny
- C. Taricco
- A. Khakurdikar
- J. Schulte
- S. Rossoni
- H. Schoorlemmer
- Luciana Andrade Dourado
- P. Schovánek
- V. Verzi
- Tomáš Fodran (ORCID: https://orcid.org/0009-0000-9529-0853)
- Megha Mogarkar
- E.-T. de Boone
- C. Dionese
Institutions
- Karlsruhe Institute of Technology (DE)
- Universidad Industrial de Santander (CO)
- University of Rome Tor Vergata (IT)
- Michigan Technological University (US)
- Universidade Federal do Rio de Janeiro (BR)
- National Technological University (AR)
- Centre National de la Recherche Scientifique (FR)
- Fermi National Accelerator Laboratory (US)
- Université Libre de Bruxelles (BE)
- Vrije Universiteit Brussel (BE)
- University of Lisbon (PT)
- University of Salento (IT)
- Radboud University Nijmegen (NL)
- Consejo Nacional de Investigaciones Científicas y Técnicas (AR)
- Federal Center for Technological Education Celso Suckow da Fonseca (BR)
- Universität Hamburg (DE)
- Lehman College (US)
- University of Wuppertal (DE)
- Colorado School of Mines (US)
- Universidad de Granada (ES)
- Universidad Michoacana de San Nicolás de Hidalgo (MX)
- City University of New York (US)
- Universidade de São Paulo (BR)
- Universidade Estadual de Campinas (UNICAMP) (BR)
- Institut Universitaire de France (FR)
- University of Milan (IT)
- University of Nova Gorica (SI)
- Universidade de Santiago de Compostela (ES)
- Université Paris Cité (FR)
- University of Siegen (DE)
- Charles University (CZ)
- Universidade Estadual de Feira de Santana (BR)
- National University of General San Martín (AR)
- Universidad de Buenos Aires (AR)
- University of L'Aquila (IT)
- Instituto Federal do Rio de Janeiro (BR)
- Université Paris-Saclay (FR)
- LIP - Laboratory of Instrumentation and Experimental Particle Physics (PT)
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso (IT)
- Folkwang University of the Arts (DE)
- Balseiro Institute (AR)
- Bariloche Atomic Centre (AR)
- Jožef Stefan Institute (SI)
- University of Łódź (PL)
- University of Catania (IT)
- Sorbonne Université (FR)
- University of Chicago (US)
- Universidade Federal de Campina Grande (BR)
- Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering (RO)
- National Institute for Subatomic Physics (NL)
- Istituto Nazionale di Fisica Nucleare, Sezione di Lecce (IT)
- Istituto Nazionale di Fisica Nucleare, Sezione di Torino (IT)
- Laboratoire de Physique Nucléaire et de Hautes Énergies (FR)
- Osservatorio Astrofisico di Torino (IT)
- Institute of Nuclear Physics, Polish Academy of Sciences (PL)
- Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (IT)
- Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata (IT)
- Institute of Scientific and Technical Research for Defense (AR)
- Istituto Nazionale di Fisica Nucleare, Sezione di Catania (IT)
- FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ)
- Centro Brasileiro de Pesquisas Físicas (BR)
- Institut National de Physique Nucléaire et de Physique des Particules (FR)
- Universidad de Medellín (CO)
- Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (FR)
- Universidad Autónoma de Chiapas (MX)
- Istituto di Astrofisica Spaziale e Fisica cosmica di Palermo (IT)
- Institute of Physics Rosario (AR)
- Istituto Nazionale di Fisica Nucleare, Sezione di Milano (IT)
- Instituto de Tecnologías en Detección y Astropartículas (AR)
- Laboratoire de Physique Subatomique et de Cosmologie (FR)
- Institute of Space Science - INFLPR Subsidiary (RO)
- Institute of Astronomy and Space Physics (AR)
- Gran Sasso Science Institute (IT)
- Pierre Auger Observatory (AR)
- International Center for Advanced Studies (AR)
- Universidade Federal do Paraná (BR)
- University of Turin (IT)
- The University of Adelaide (AU)
- New York University (US)
- Case Western Reserve University (US)
- Instituto Politécnico Nacional (MX)
- Palacký University Olomouc (CZ)
- University of Naples Federico II (IT)
- Universidade Federal do ABC (BR)
- Benemérita Universidad Autónoma de Puebla (MX)
- University of Delaware (US)
- Universidad Nacional de La Plata (AR)
- University of Amsterdam (NL)
- RWTH Aachen University (DE)
- Universidad Nacional Autónoma de México (MX)
- Université Grenoble Alpes (FR)
- University of Palermo (IT)
- Netherlands Institute for Radio Astronomy (NL)
- Comisión Nacional de Energía Atómica (AR)
- Politecnico di Milano (IT)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-06-27
- DOI
- https://doi.org/10.3847/1538-4357/adccc3
- Citations
- 2
- Primary Topic
- Solar and Space Plasma Dynamics
- Type
- article
- Field-Weighted Citation Impact
- 2.31
Funders
- National Science Foundation
- U.S. Department of Energy
- Grainger Foundation
- Ministerul Cercetării, Inovării şi Digitalizării
- European Commission
- Fundação de Amparo à Pesquisa do Estado de São Paulo
- Fonds Wetenschappelijk Onderzoek
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek
- Javna Agencija za Raziskovalno Dejavnost RS
- Ministerio de Ciencia e Innovación
- Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii
- Xunta de Galicia
- Junta de Andalucía
- Fundação para a Ciência e a Tecnologia
- Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México
- European Regional Development Fund
- Agencia Estatal de Investigación