159 research outputs found
Evidence for a mixed mass composition at the ‘ankle’ in the cosmic-ray spectrum
No full textWe report a first measurement for ultrahigh energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the ‘ankle’ at lg(E/eV)=18.5–19.0lg(E/eV)=18.5–19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A>4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavored as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth
Erratum: Search for photons with energies above 1018 eV using the hybrid detector of the Pierre Auger Observatory (Journal of Cosmology and Astroparticle Physics (2017) 4 (9) DOI: 10.1088/1475-7516/2017/04/009)
No full text1 Exposure calculation Due to a mistake in the numerical integration following eq. (6.2) of the original article [1], the exposure shown in figure 5 of the original article was incorrect. The correct exposure is shown in figure 1. 2 Upper limits on the integral photon flux and fraction The incorrect exposure affects the calculation of the upper limits on the integral photon flux following eq. (6.1) of the original article. The correct values for the upper limits are 0.038, 0.010, 0.009, 0.008 and 0.007 km−2 sr−1 yr−1 for threshold energies of 1, 2, 3, 5 and 10 EeV. The correct values for the upper limits on the integral photon fraction subsequently derived are 0.14 %, 0.17 %, 0.42 %, 0.86 % and 2.9 % for the same threshold energies. 3 Author list The author list of this erratum also corrects a mistake made in the original article, where F. Zuccarello was missing and Z. Zong was listed twice
Erratum: Search for photons with energies above 1018 eV using the hybrid detector of the Pierre Auger Observatory
No full textExposure calculation Due to a mistake in the numerical integration following eq. (6.2) of the original article [1], the exposure shown in figure 5 of the original article was incorrect. The correct exposure is shown in figure 1. 2 Upper limits on the integral photon flux and fraction The incorrect exposure affects the calculation of the upper limits on the integral photon flux following eq. (6.1) of the original article. The correct values for the upper limits are 0.038, 0.010, 0.009, 0.008 and 0.007 km−2 sr−1 yr−1 for threshold energies of 1, 2, 3, 5 and 10 EeV. The correct values for the upper limits on the integral photon fraction subsequently derived are 0.14 %, 0.17 %, 0.42 %, 0.86 % and 2.9 % for the same threshold energies. 3 Author list The author list of this erratum also corrects a mistake made in the original article, where F. Zuccarello was missing and Z. Zong was listed twice
A 3-Year Sample of Almost 1,600 Elves Recorded Above South America by the Pierre Auger Cosmic-Ray Observatory
No full textElves are a class of transient luminous events, with a radial extent typically greater than 250 km, that occur in the lower ionosphere above strong electrical storms.We report the observation of 1,598 elves, from 2014 to 2016, recorded with unprecedented time resolution (100 ns) using the fluorescence detector (FD) of the Pierre Auger Cosmic-Ray Observatory. The Auger Observatory is located in the Mendoza province of Argentina with a viewing footprint for elve observations of 3 · 106 km2, reaching areas above the Pacific and Atlantic Oceans, as well as the Córdoba region, which is known for severe convective thunderstorms. Primarily designed for ultrahigh energy cosmic-ray observations, the Auger FD turns out to be very sensitive to the ultraviolet emission in elves. The detector features modified Schmidt optics with large apertures resulting in a field of view that spans the horizon, and year-round operation on dark nights with low moonlight background, when the local weather is favorable. The measured light profiles of 18% of the elve events have more than one peak, compatible with intracloud activity. Within the 3-year sample, 72% of the elves correlate with the far-field radiation measurements of the World Wide Lightning Location Network. The Auger Observatory plans to continue operations until at least 2025, including elve observations and analysis. To the best of our knowledge, this observatory is the only facility on Earth that measures elves with year-round operation and full horizon coverage.
Co-authors: A. Aab, P. Abreu,M. Aglietta, I. F.M. Albuquerque, J.M. Albury, I. Allekotte, A. Almela, J. Alvarez Castillo, J. Alvarez-Muniz, G. A. Anastasi,L. Anchordoqui, B. Andrada, S. Andringa, C. Aramo, H. Asorey, P. Assis, G. Avila, A.M. Badescu, A. Bakalova, A. Balaceanu,F. Barbato, R. J. Barreira Luz, S. Baur, K. H. Becker, J.A. Bellido, C. Berat,M. E. Bertaina, X. Bertou, P. L. Biermann, J. Biteau, S. G. Blaess, A. Blanco, J. Blazek, C. Bleve,M. Bohaˇcova, D. Boncioli, C. Bonifazi, N. Borodai, A. M. Botti, J. Brack,T. Bretz, A. Bridgeman, F. L. Briechle, P. Buchholz, A. Bueno, S. Buitink,M. Buscemi, K. S. Caballero-Mora, L. Caccianiga, L. Calcagni, A. Cancio, F. Canfora, J.M. Carceller, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon,M. Cerda, J. A. Chinellato,J. Chudoba, L. Chytka, R.W. Clay, A. C. Cobos Cerutti, R. Colalillo, A. Coleman,M. R. Coluccia, R. Conceicao, A. Condorelli, G. Consolati,F. Contreras,M. J. Cooper, S. Coutu, C. E. Covault, B. Daniel, S. Dasso, K. Daumiller, B. R. Dawson, J. A. Day, R.M. de Almeida,S. J. de Jong, G. Mauro, J. R. T. de Mello Neto, I. Mitri, J. de Oliveira, F. O. de Oliveira Salles, V. de Souza, J. Debatin,M. del Rio, O. Deligny,N. Dhital,M. L. Diaz Castro, F. Diogo, C. Dobrigkeit, J. C. D\u27Olivo, Q. Dorosti, R. C. dos Anjos, M. T. Dova, A. Dundovic, J. Ebr, R. Engel,M. Erdmann, C. O. Escobar, A. Etchegoyen, H. Falcke, J. Farmer, G. Farrar, A. C. Fauth, N. Fazzini, F. Feldbusch,F. Fenu, L. P. Ferreyro, J.M. Figueira, A. Filipˇciˇc, M. M. Freire, T. Fujii, A. Fuster, B. Garcia, H. Gemmeke, A. Gherghel-Lascu,P. L. Ghia, U. Giaccari,M. Giammarchi,M. Giller, D. Głas, J. Glombitza, F. Gobbi, G. Golup,M. Gomez Berisso, P. F. Gomez Vitale,J. P. Gongora, N. Gonzalez, I. Goos, D. Gora, A. Gorgi,M. Gottowik, T. D. Grubb, F. Guarino, G. P. Guedes, E. Guido,R. Halliday, M. R. Hampel, P. Hansen, D. Harari, T. A. Harrison, V. M. Harvey, A. Haungs, T. Hebbeker, D. Heck, P. Heimann,G. C. Hill, C. Hojvat, E. M. Holt, P. Homola, J. R. Horandel, P. Horvath,M. Hrabovsky, T. Huege, J. Hulsman, A. Insolia,P. G. Isar, I. Jandt, J. A. Johnsen,M. Josebachuili, J. Jurysek, A. Kaapa, K. H. Kampert, B. Keilhauer, N. Kemmerich, J. Kemp,H. O. Klages, M. Kleifges, J. Kleinfeller, R. Krause, D. Kuempel, G. Kukec Mezek, A. Kuotb Awad, B. L. Lago, D. LaHurd, R. G. Lang,R. Legumina,M. A. Leigui de Oliveira, V. Lenok, A. Letessier-Selvon, I. Lhenry-Yvon, O. C. Lippmann, D. Lo Presti, L. Lopes, R. Lopez, A. Lopez Casado,R. Lorek, Q. Luce, A. Lucero,M. Malacari, G. Mancarella, D. Mandat, B. C. Manning, P. Mantsch, A. G. Mariazzi, I. C. Mari，s, G. Marsella, D. Martello, H. Martinez, O. Martinez Bravo,M. Mastrodicasa, H. J. Mathes, S. Mathys, J. Matthews, G. Matthiae, E. Mayotte,P. O. Mazur, G. Medina-Tanco, D. Melo, A. Menshikov, K.-D. Merenda, S. Michal,M. I. Micheletti, L. Middendorf, L. Miramonti, B. Mitrica,D. Mockler, S. Mollerach, F. Montanet, C. Morello, G. Morlino,M. Mostafa, A. L. Muller,M. A. Muller, S. Muller, R. Mussa,L. Nellen, P. H. Nguyen,M. Niculescu-Oglinzanu,M. Niechciol, D. Nitz, D. Nosek, V. Novotny, L. Noža, A Nucita, L.A. Nunez,A. Olinto,M. Palatka, J. Pallotta,M. P. Panetta, P. Papenbreer, G. Parente, A. Parra, M. Pech, F. Pedreira, J. Pe，kala,R. Pelayo, J. Pena-Rodriguez, L. A. S. Pereira,M. Perlin, L. Perrone, C. Peters, S. Petrera, J. Phuntsok, T. Pierog,M. Pimenta,V. Pirronello,M. Platino, J. Poh, B. Pont, C. Porowski, R. R. Prado, P. Privitera,M. Prouza, A. Puyleart, S. Querchfeld,S. Quinn, R. Ramos-Pollan, J. Rautenberg, D. Ravignani, M. Reininghaus, J. Ridky, F. Riehn,M. Risse, P. Ristori, V. Rizi, W. Rodrigues de Carvalho, J. Rodriguez Rojo,M. J. Roncoroni, M. Roth, E. Roulet, A. C. Rovero, P. Ruehl, S. J. Saffi, A. Saftoiu, F. Salamida,H. Salazar, G. Salina,J. D. Sanabria Gomez, F. Sanchez, E.M. Santos, E. Santos, F. Sarazin, R. Sarmento, C. Sarmiento-Cano, R. Sato,P. Savina,M. Schauer, V. Scherini, H. Schieler, M. Schimassek,M. Schimp, F. Schluter, D. Schmidt, O. Scholten, P. Schovanek, F. G. Schroder, S. Schroder, J. Schumacher, S. J. Sciutto,M. Scornavacche, R. C. Shellard, G. Sigl, G. Silli, O. Sima, R. Šmida,G.R. Snow, P. Sommers, J. F. Soriano, J. Souchard, R. Squartini, D. Stanca, S. Staniˇc, J. Stasielak, P. Stassi, M. Stolpovskiy,A. Streich, F. Suarez,M. Suarez-Duran, T. Sudholz, T. Suomijarvi, A.D. Supanitsky, J. Šupik, Z. Szadkowski, A. Taboada, O. A. Taborda, A. Tapia, C. Timmermans, C. J. Todero Peixoto, B. Tome, G. Torralba Elipe, A. Travaini, P. Travnicek,M. Trini, M. Tueros, R. Ulrich,M. Unger,M. Urban, J. F. Valdes Galicia, I. Valino, L. Valore, P. van Bodegom, A.M. van den Berg, A. van Vliet, E. Varela, B. Vargas Cardenas,D. Veberiˇc, C. Ventura, I. D. Vergara Quispe, V. Verzi, J. Vicha, L. Villasenor, J. Vink, S. Vorobiov, H. Wahlberg, A. A. Watson, M. Weber, A. Weindl,M.Wieden´ ski, L. Wiencke, H. Wilczyn´ ski, T.Winchen, M. Wirtz, D. Wittkowski, B. Wundheiler, L. Yang, A. Yushkov, E. Zas, D. Zavrtanik, M. Zavrtanik, L. Zehrer, A. Zepeda, B. Zimmermann,M. Ziolkowski, Z. Zongand F. Zuccarello
Data set attached as supplementary file
Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 1018 eV
No full textCosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using 3 × 104 cosmic rays with energies above 8 × 1018 electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km2 sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2σ level of significance, can be described by a dipole with an amplitude of Embedded Image percent toward right ascension αd = 100 ± 10 degrees and declination δd = Embedded Image degrees. That direction indicates an extragalactic origin for these ultrahigh-energy particles
Atmospheric Monitoring at a Cosmic Ray Observatory - a long-lasting endeavour
No full textThe Pierre Auger Observatory for detecting ultrahigh energy cosmic rays has been founded in 1999. After a main planning and construction phase of about five years, the regular data taking started in 2004, but it took another four years until the full surface detector array was deployed. In parallel to the main detectors of the Observatory, a comprehensive set of instruments for monitoring the atmospheric conditions above the array was developed and installed as varying atmospheric conditions influence the development and detection of extensive air showers.The multitude of atmospheric monitoring installations at the Pierre Auger Observatory will be presented as well as the challenges and efforts to run such instruments for several decades
A 3-Year Sample of Almost 1,600 Elves Recorded Above South America by the Pierre Auger Cosmic-Ray Observatory
No full textThe time and location of the 1,598
verified and reconstructed elves, used
for the analysis showcased in this
paper, are publicly available on the
website of the Pierre Auger
Observatory (https://www.auger.org/
index.php/science/data). We wish to
thank the World Wide Lightning
Location Network (http://wwlln.net),
a collaboration among over 50
universities and institutions, for
providing the lightning location data
used in this paper. We acknowledge
Robert Marshall for providing one of
the most advanced elve simulations to
the public, a key tool in understanding
the elves observed by the Pierre Auger
Observatory. The successful
installation, commissioning, and
operation of the Pierre Auger
Observatory would not have been
possible without the strong
commitment and effort from the
technical and administrative staff in
Malargüe.Elves are a class of transient luminous events, with a radial extent typically greater than
250 km, that occur in the lower ionosphere above strong electrical storms. We report the observation of
1,598 elves, from 2014 to 2016, recorded with unprecedented time resolution (100 ns) using the
fluorescence detector (FD) of the Pierre Auger Cosmic-Ray Observatory. The Auger Observatory is located
in the Mendoza province of Argentina with a viewing footprint for elve observations of 3 · 106 km2,
reaching areas above the Pacific and Atlantic Oceans, as well as the Córdoba region, which is known for
severe convective thunderstorms. Primarily designed for ultrahigh energy cosmic-ray observations, the
Auger FD turns out to be very sensitive to the ultraviolet emission in elves. The detector features modified
Schmidt optics with large apertures resulting in a field of view that spans the horizon, and year-round
operation on dark nights with low moonlight background, when the local weather is favorable. The
measured light profiles of 18% of the elve events have more than one peak, compatible with intracloud
activity. Within the 3-year sample, 72% of the elves correlate with the far-field radiation measurements of
the World Wide Lightning Location Network. The Auger Observatory plans to continue operations until at
least 2025, including elve observations and analysis. To the best of our knowledge, this observatory is the
only facility on Earth that measures elves with year-round operation and full horizon coverage.Argentina—Comisión Nacional de
Energía Atómica; Agencia Nacional de
Promoción Científica y Tecnológica
(ANPCyT); Consejo Nacional de
Investigaciones Científicas y Técnicas
(CONICET); Gobierno de la Provincia
de Mendoza; Municipalidad de
Malargüe; and NDM Holdings and
Valle Las Leñas, in gratitude for their
continuing cooperation over land
access; Australia—the Australian
Research Council; Brazil—Conselho
Nacional de Desenvolvimento
Científico e Tecnológico (CNPq);
Financiadora de Estudos e Projetos
(FINEP); Fundação de Amparo à
Pesquisa do Estado de Rio de Janeiro
(FAPERJ); São Paulo Research
Foundation (FAPESP) Grants
2010/07359-6 and 1999/05404-3;
Ministério da Ciência, Tecnologia,
Inovações e Comunicações
(MCTIC); Czech Republic—Grants
MSMT CRLTT18004,
LO1305, LM2015038, and
CZ.02.1.01/0.0/0.0/16_013/0001402;
France—Centre de Calcul
IN2P3/CNRS; Centre National de la
Recherche Scientifique (CNRS);
Conseil Régional Ile-de-France;
Département Physique Nucléaire et
Corpusculaire (PNC-IN2P3/CNRS);
Département Sciences de l'Univers
(SDU-INSU/CNRS); Institut Lagrange
de Paris (ILP) Grant LABEX
ANR-10-LABX-63 within the
Investissements d'Avenir Programme
Grant ANR-11-IDEX-0004-02;
Germany—Bundesministerium für
Bildung und Forschung (BMBF);
Deutsche Forschungsgemeinschaft
(DFG); Finanzministerium
Baden-Württemberg; Helmholtz
Alliance for Astroparticle Physics
(HAP); Helmholtz-Gemeinschaft. Deutscher Forschungszentren (HGF);
Ministerium für Innovation,
Wissenschaft und Forschung des
Landes Nordrhein-Westfalen;
Ministerium für Wissenschaft,
Forschung und Kunst des Landes
Baden-Württemberg; Italy—Istituto
Nazionale di Fisica Nucleare (INFN);
Istituto Nazionale di Astrofisica
(INAF); Ministero dell'Istruzione,
dell'Universitá e della Ricerca (MIUR);
CETEMPS Center of Excellence;
Ministero degli Affari Esteri (MAE);
México—Consejo Nacional de Ciencia
y Tecnología (CONACYT)167733;
Universidad Nacional Autónoma de
México (UNAM); PAPIIT
DGAPA-UNAM; The
Netherlands—Ministry of Education,
Culture and Science; Netherlands
Organisation for Scientific Research
(NWO); Dutch National
e-Infrastructure with the support of
SURF Cooperative; Poland—National
Centre for Research and Development,
Grant ERA-NET-ASPERA/02/11;
National Science Centre, Grants
2013/08/M/ST9/00322,
2016/23/B/ST9/01635, and
HARMONIA
5–2013/10/M/ST9/00062,
UMO-2016/22/M/ST9/00198;
Portugal—Portuguese national funds
and FEDER funds within Programa
Operacional Factores de
Competitividade through Fundação
para a Ciência e a Tecnologia
(COMPETE); Romania—Romanian
Ministry of Research and
InnovationCNCS/CCCDI-UESFISCDI,
projects PN-III-P1-1.2-PCCDI-2017-
0839/19PCCDI/2018,
PN-III-P2-2.1-PED-2016-1922,
PN-III-P2-2.1-PED-2016-1659, and
PN18090102 within PNCDI III;
Slovenia—Slovenian Research
Agency; Spain—Comunidad de
Madrid; Fondo Europeo de Desarrollo
Regional (FEDER) funds; Ministerio
de Economía y Competitividad; Xunta
de Galicia; European Community 7th
Framework Program Grant
FP7-PEOPLE-2012-IEF-328826;
USA—Department of Energy,
Contracts DE-AC02-07CH11359,
DE-FR02-04ER41300,
DE-FG02-99ER41107, and
DE-SC0011689; National Science
Foundation, Grant 0450696; The
Grainger Foundation; Marie
Curie-IRSES/EPLANET; European
Particle Physics Latin American
Network; European Union 7th
Framework Program, Grant
PIRSES-2009-GA-246806; and
UNESCO
A targeted search for point sources of EeV photons with the Pierre Auger Observatory
No full text9 pages, 2 figures, submitted to The Astrophysical Journal LettersInternational audienceSimultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in classes to avoid the statistical penalty for making many trials and analyzed for a significant excess above the background expectation. The presented search does not find any evidence for photon emission at candidate sources, and combined -values for every class are reported. Particle and energy flux upper limits are given for selected candidate sources. These limits significantly constrain predictions of EeV proton emission models from non-transient Galactic and nearby extragalactic sources as illustrated for the particular case of the Galactic center region
A search for pair production of new light bosons decaying into muons
No full textA search for the pair production of new light bosons, each decaying into a pair of muons, is performed with the CMS experiment at the LHC, using a dataset corresponding to an integrated luminosity of 20.7fb−1collected in proton–proton collisions at center-of-mass energy of √s=8TeV. No excess is observed in the data relative to standard model background expectation and a model independent up-per limit on the product of the cross section, branching fraction, and acceptance is derived. The results are compared with two benchmark models, the first one in the context of the next-to-minimal super-symmetric standard model, and the second one in scenarios containing a hidden sector, including those predicting a nonnegligible light boson lifetime.LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MOST, and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); MoER, ERC IUT and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and National Science Foundation(USA)
Multi-Messenger Physics with the Pierre Auger Observatory
No full textInternational audienceAn overview of the multi-messenger capabilities of the Pierre Auger Observatory is presented. The techniques and performance of searching for Ultra-High Energy neutrinos, photons and neutrons are described. Some of the most relevant results are reviewed, such as stringent upper bounds that were placed to a flux of diffuse cosmogenic neutrinos and photons, bounds placed on neutrinos emitted from compact binary mergers that were detected by LIGO and Virgo during their first and second observing runs, as well as searches for high energy photons and neutrons from the Galactic center that constrain the properties of the putative Galactic PeVatron, observed by the H.E.S.S.\ collaboration. The observation of directional correlations between ultra-high energy cosmic rays and either high energy astrophysical neutrinos or specific source populations, weighted by their electromagnetic radiation, are also discussed. They constitute additional multi-messenger approaches aimed at identifying the sources of high energy cosmic rays
- …
