Hybrid cosmic ray measurements using the IceAct telescopes in coincidence with the IceCube and IceTop detectors

IceAct is a proposed surface array of compact (50 cm diameter) and cost-effective Imaging Air Cherenkov Telescopes installed at the site of the IceCube Neutrino Observatory at the geographic South Pole. Since January 2019, two IceAct telescope demonstrators, featuring 61 silicon photomultiplier (SiPM) pixels have been taking data in the center of the IceTop surface array during the austral winter. We present the first analysis of hybrid cosmic ray events detected by the IceAct imaging air-Cherenkov telescopes in coincidence with the IceCube Neutrino Observatory, including the IceTop surface array and the IceCube in-ice array. By featuring an energy threshold of about 10 TeV and a wide field-of-view, the IceAct telescopes show promising capabilities of improving current cosmic ray composition studies: measuring the Cherenkov light emissions in the atmosphere adds new information about the shower development not accessible with the current detectors, enabling significantly better primary particle type discrimination on a statistical basis. The hybrid measurement also allows for detailed feasibility studies of detector cross-calibration and of cosmic ray veto capabilities for neutrino analyses. We present the performance of the telescopes, the results from the analysis of two years of data, and an outlook of a hybrid simulation for a future telescope array

Three-year performance of the IceAct telescopes at the IceCube Neutrino Observatory

IceAct is an array of compact Imaging Air Cherenkov Telescopes at the ice surface as part of the IceCube Neutrino Observatory. The telescopes, featuring a camera of 61 silicon photomultipliers and fresnel-lens-based optics, are optimized to be operated in harsh environmental conditions, such as at the South Pole. Since 2019, the first two telescopes have been operating in a stereoscopic configuration in the center of IceCube\u27s surface detector IceTop. With an energy threshold of about 10 TeV and a wide field-of-view, the IceAct telescopes show promising capabilities of improving current cosmic-ray composition studies: measuring the Cherenkov light emissions in the atmosphere adds new information about the shower development not accessible with the current detectors. First simulations indicate that the added information of a single telescope leads, e.g., to an improved discrimination between flux contributions from different primary particle species in the sensitive energy range. We review the performance and detector operations of the telescopes during the past 3 years (2020-2022) and give an outlook on the future of IceAct

FACT - Multi-wavelength analysis of more than 30 flares of Mrk 421

Mrk 421 is a high-synchrotron-peaked blazar featuring bright and persistent GeV and TeV emission. We use multi-wavelength light curves of Mrk 421 spanning 5.5 years with FACT (TeV) and Fermi LAT (GeV) in the gamma rays, Swift BAT, Swift XRT and MAXI in the X-rays, together with optical and radio data and investigate the physical processes driving the emission and variability. Observations by FACT are continuous and not triggered, so the source was found in a wide range of flux states and more than 30 flares were identified from X-rays to TeV. The light curves in TeV and X-rays feature very similar flares with rise and decay times of a few days and zero lag, characteristic for electron processes. At least two parameters per flare, the amplitude and the cut-off energy, are required to explain the observed variability. In addition, the GeV light curve leads and is strongly correlated with the optical and radio light curves as expected from SSC emitting shock propagating in a conical jet.ISSN:1824-803

Measurement of the Fluctuations in the Number of Muons in Extensive Air Showers with 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 Malargue. We are very grateful to the following agencies and organizations for financial support: Argentina-Comision Nacional de Energia Atomica, Agencia Nacional de Promocion Cientifica y Tecnologica (ANPCyT), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Gobierno de la Provincia de Mendoza, Municipalidad de Malargue, NDM Holdings and Valle Las Lenas; in gratitude for their continuing cooperation over land access; Australia-the Australian Research Council; BrazilConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundacao de Amparo a Pesquisa do Estado de Rio de Janeiro (FAPERJ), Sao Paulo Research Foundation (FAPESP) Grants No. 2019/10151-2, No. 2010/07359-6, and No. 1999/05404-3, Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (MCTIC); Ministry of Education, Youth and Sports of the Czech RepublicGrants No. MSMT CR LTT18004, No. LM2015038, No. LM2018102, No. CZ.02.1.01/0.0/0.0/16_013/0001402, No. CZ.02.1.01/0.0/0.0/18_046/0016010, and No. CZ.02.1.01/0.0/0.0/17_049/0008422; France-Centre de Calcul IN2P3/CNRS, Centre National de la Recherche Scientifique (CNRS), Conseil Regional Ile-de-France, Departement Physique Nucl ' eaire et Corpusculaire (PNC-IN2P3/CNRS), Departement Sciences de l'Univers (SDU-INSU/CNRS), Institut Lagrange de Paris (ILP) Grant No. LABEX ANR-10-LABX-63 within the Investissements d'Avenir Programme Grant No. ANR11-IDEX-0004-02; Germany-Bundesministerium fur Bildung und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DFG), Finanzministerium Baden-Wurttemberg, Helmholtz Alliance for Astroparticle Physics (HAP), Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF), Ministerium fur Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen, Ministerium fur Wissenschaft, Forschung und Kunst des Landes Baden-Wurttemberg; Italy-Istituto Nazionale di Fisica Nucleare (INFN), Istituto Nazionale di Astrofisica (INAF), Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR), CETEMPS Center of Excellence, Ministero degli Affari Esteri (MAE); Mexico-Consejo Nacional de Ciencia y Tecnologia (CONACYT) Grant No. 167733, Universidad Nacional Autonoma de Mexico (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-Ministry of Science and Higher Education, Grant No. DIR/WK/2018/11, National Science Centre, Grants No. 2013/08/M/ST9/00322, No. 2016/23/B/ST9/01635, and No. 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 Fundacao para a Ciencia e a Tecnologia (COMPETE); Romania-Romanian Ministry of Education and Research, the Program Nucleu within MCI (PN19150201/16N/2019 and PN19060102), and project PN-III-P1-1.2-PCCDI-2017-0839/19PCCDI/2018 within PNCDI III; Slovenia-Slovenian Research Agency, Grants No. P1-0031, No. P1-0385, No. I00033, No. N1-0111; Spain-Ministerio de Economia, Industria y Competitividad (FPA2017-85114-P and FPA2017-85197-P), Xunta de Galicia (ED431C 2017/07), Junta de Andalucia (SOMM17/6104/UGR), Feder Funds, RENATA Red Nacional Tematica de Astroparticulas (FPA2015-68783-REDT), and Maria de Maeztu Unit of Excellence (MDM-2016-0692); U.S.Department of Energy, Awards No. DE-AC0207CH11359, No. DE-FR02-04ER41300, No. DE-FG0299ER41107, and No. DE-SC0011689, National Science Foundation, Grant No. 0450696, The Grainger Foundation, Marie Curie-IRSES/EPLANET, European Particle Physics Latin American Network, and UNESCO.We present the first measurement of the fluctuations in the number of muons in extensive air showers produced by ultrahigh energy cosmic rays. We find that the measured fluctuations are in good agreement with predictions from air shower simulations. This observation provides new insights into the origin of the previously reported deficit of muons in air shower simulations and constrains models of hadronic interactions at ultrahigh energies. Our measurement is compatible with the muon deficit originating from small deviations in the predictions from hadronic interaction models of particle production that accumulate as the showers develop.Argentina-Comision Nacional de Energia AtomicaANPCyTConsejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET)Gobierno de la Provincia de MendozaMunicipalidad de MalargueNDM HoldingsValle Las LenasAustralian Research CouncilConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF)Financiadora de Inovacao e Pesquisa (Finep)Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2019/10151-2 2010/07359-6 1999/05404-3Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (MCTIC)Ministry of Education, Youth & Sports - Czech Republic MSMT CR LTT18004 LM2015038 LM2018102 CZ.02.1.01/0.0/0.0/16_013/0001402 CZ.02.1.01/0.0/0.0/18_046/0016010 CZ.02.1.01/0.0/0.0/17_049/0008422France-Centre de Calcul IN2P3/CNRSCentre National de la Recherche Scientifique (CNRS)Region Ile-de-FranceCentre National de la Recherche Scientifique (CNRS)Departement Sciences de l'Univers (SDU-INSU/CNRS)French National Research Agency (ANR) LABEX ANR-10-LABX-63 ANR11-IDEX-0004-02Federal Ministry of Education & Research (BMBF)German Research Foundation (DFG)Finanzministerium Baden-WurttembergHelmholtz Alliance for Astroparticle Physics (HAP)Helmholtz AssociationMinisterium fur Innovation, Wissenschaft und Forschung des Landes Nordrhein-WestfalenMinisterium fur Wissenschaft, Forschung und Kunst des Landes Baden-WurttembergItaly-Istituto Nazionale di Fisica Nucleare (INFN)Istituto Nazionale Astrofisica (INAF)Ministry of Education, Universities and Research (MIUR)CETEMPS Center of ExcellenceMinistry of Foreign Affairs and International Cooperation (Italy)Consejo Nacional de Ciencia y Tecnologia (CONACyT) 167733Universidad Nacional Autonoma de Mexico (UNAM), PAPIIT DGAPA-UNAMNetherlands-Ministry of Education, Culture and ScienceNetherlands Organization for Scientific Research (NWO)Dutch national e-infrastructureSURF CooperativePoland-Ministry of Science and Higher Education DIR/WK/2018/11National Science Centre, Poland 2013/08/M/ST9/00322 2016/23/B/ST9/01635 HARMONIA 5-2013/10/M/ST9/00062 UMO-2016/22/M/ST9/00198Portugal -Portuguese national fundsFEDER funds within Programa Operacional Factores de Competitividade through Fundacao para a Ciencia e a Tecnologia (COMPETE)Romania-Romanian Ministry of Education and Research, the Program Nucleu within MCI PN19150201/16N/2019 PN19060102Romania-Romanian Ministry of Educatio n and Research, the Program Nucleu within PNCDI III PN-III-P1-1.2-PCCDI-2017-0839/19PCCDI/2018Slovenian Research Agency - Slovenia P1-0031 P1-0385 I00033 N1-0111Spain-Ministerio de Economia, Industria y Competitividad FPA2017-85114-P FPA2017-85197-PXunta de Galicia European Commission ED431C 2017/07Junta de Andalucia SOMM17/6104/UGREuropean CommissionRENATA Red Nacional Tematica de Astroparticulas FPA2015-68783-REDTMaria de Maeztu Unit of Excellence MDM-2016-0692United States Department of Energy (DOE) DE-AC0207CH11359 DE-FR02-04ER41300 DE-FG0299ER41107 DE-SC0011689National Science Foundation (NSF) 0450696Grainger FoundationMarie Curie-IRSES/EPLANETEuropean Particle Physics Latin American NetworkUNESC

Recording, analysis, and interpretation of spreading depolarizations in neurointensive care : Review and recommendations of the COSBID research group

Spreading depolarizations (SD) are waves of abrupt, near-complete breakdown of neuronal transmembrane ion gradients, are the largest possible pathophysiologic disruption of viable cerebral gray matter, and are a crucial mechanism of lesion development. Spreading depolarizations are increasingly recorded during multimodal neuromonitoring in neurocritical care as a causal biomarker providing a diagnostic summary measure of metabolic failure and excitotoxic injury. Focal ischemia causes spreading depolarization within minutes. Further spreading depolarizations arise for hours to days due to energy supply-demand mismatch in viable tissue. Spreading depolarizations exacerbate neuronal injury through prolonged ionic breakdown and spreading depolarization-related hypoperfusion (spreading ischemia). Local duration of the depolarization indicates local tissue energy status and risk of injury. Regional electrocorticographic monitoring affords even remote detection of injury because spreading depolarizations propagate widely from ischemic or metabolically stressed zones; characteristic patterns, including temporal clusters of spreading depolarizations and persistent depression of spontaneous cortical activity, can be recognized and quantified. Here, we describe the experimental basis for interpreting these patterns and illustrate their translation to human disease. We further provide consensus recommendations for electrocorticographic methods to record, classify, and score spreading depolarizations and associated spreading depressions. These methods offer distinct advantages over other neuromonitoring modalities and allow for future refinement through less invasive and more automated approaches