Astroparticle Physics最新文献

{"title":"Cosmic-ray physics at the South Pole","authors":"D. Soldin ,&nbsp;P.A. Evenson ,&nbsp;H. Kolanoski ,&nbsp;A.A. Watson","doi":"10.1016/j.astropartphys.2024.102992","DOIUrl":"10.1016/j.astropartphys.2024.102992","url":null,"abstract":"<div><p>The geographic South Pole provides unique opportunities to study cosmic particles in the Southern Hemisphere. It represents an optimal location to deploy large-scale neutrino telescopes in the deep Antarctic ice, such as AMANDA or IceCube. In both cases, the presence of an array, constructed to observe extensive air showers, enables hybrid measurements of cosmic rays. While additional neutron monitors can provide information on solar cosmic rays, large detector arrays, like SPASE or IceTop, allow for precise measurements of cosmic rays with energies above several <span><math><mrow><mn>100</mn><mspace></mspace><mi>TeV</mi></mrow></math></span>. In coincidence with the signals recorded in the deep ice, which are mostly due to the high-energy muons produced in air showers, this hybrid detector setup provides important information about the nature of cosmic rays.</p><p>In this review, we will discuss the historical motivation and developments towards measurements of cosmic rays at the geographic South Pole and highlight recent results reported by the IceCube Collaboration. We will emphasize the important contributions by Thomas K. Gaisser and his colleagues that ultimately led to the rich Antarctic research program which today provides crucial insights into cosmic-ray physics.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102992"},"PeriodicalIF":3.5,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141194999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Background study of the AMoRE-pilot experiment","authors":"A. Agrawal,&nbsp;V.V. Alenkov,&nbsp;P. Aryal,&nbsp;J. Beyer,&nbsp;B. Bhandari,&nbsp;R.S. Boiko,&nbsp;K. Boonin,&nbsp;O. Buzanov,&nbsp;C.R. Byeon,&nbsp;N. Chanthima,&nbsp;M.K. Cheoun,&nbsp;J.S. Choe,&nbsp;Seonho Choi,&nbsp;S. Choudhury,&nbsp;J.S. Chung,&nbsp;F.A. Danevich,&nbsp;M. Djamal,&nbsp;D. Drung,&nbsp;C. Enss,&nbsp;A. Fleischmann,&nbsp;Q. Yue","doi":"10.1016/j.astropartphys.2024.102991","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102991","url":null,"abstract":"<div><p>We report a study on the background of the Advanced Molybdenum-Based Rare process Experiment (AMoRE), a search for neutrinoless double beta decay (<span><math><mrow><mn>0</mn><mi>ν</mi><mi>β</mi><mi>β</mi></mrow></math></span>) of ¹⁰⁰Mo. The pilot stage of the experiment was conducted using <span><math><mo>∼</mo></math></span>1.9 kg of <span><math><msup><mrow></mrow><mrow><mn>48</mn><mi>depl</mi></mrow></msup></math></span>Ca<span><math><msup><mrow></mrow><mrow><mn>100</mn></mrow></msup></math></span>MoO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span> crystals at the Yangyang Underground Laboratory, South Korea, from 2015 to 2018. We compared the measured <span><math><mrow><mi>β</mi><mo>/</mo><mi>γ</mi></mrow></math></span> energy spectra in three experimental configurations with the results of Monte Carlo simulations and identified the background sources in each configuration. We replaced several detector components and enhanced the neutron shielding to lower the background level between configurations. A limit on the half-life of <span><math><mrow><mn>0</mn><mi>ν</mi><mi>β</mi><mi>β</mi></mrow></math></span> decay of ¹⁰⁰Mo was found at <span><math><mrow><msubsup><mrow><mi>T</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow><mrow><mn>0</mn><mi>ν</mi></mrow></msubsup><mo>≥</mo><mn>3</mn><mo>.</mo><mn>0</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>23</mn></mrow></msup></mrow></math></span> years at 90% confidence level, based on the measured background and its modeling. Further reduction of the background rate in the AMoRE-I and AMoRE-II are discussed.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"162 ","pages":"Article 102991"},"PeriodicalIF":3.5,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141290320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential Sensitivity of the KM3NeT/ARCA detector to a diffuse neutrino flux and to point-like source emission: Exploring the case of the Starburst Galaxies","authors":"S. Aiello ,&nbsp;A. Albert ,&nbsp;M. Alshamsi ,&nbsp;S. Alves Garre ,&nbsp;Z. Aly ,&nbsp;A. Ambrosone ,&nbsp;F. Ameli ,&nbsp;M. Andre ,&nbsp;E. Androutsou ,&nbsp;M. Anguita ,&nbsp;L. Aphecetche ,&nbsp;M. Ardid ,&nbsp;S. Ardid ,&nbsp;H. Atmani ,&nbsp;J. Aublin ,&nbsp;F. Badaracco ,&nbsp;L. Bailly-Salins ,&nbsp;Z. Bardačová ,&nbsp;B. Baret ,&nbsp;A. Bariego-Quintana ,&nbsp;N. Zywucka","doi":"10.1016/j.astropartphys.2024.102990","DOIUrl":"10.1016/j.astropartphys.2024.102990","url":null,"abstract":"<div><p>KM3NeT/ARCA is a Cherenkov neutrino telescope under construction in the Mediterranean sea, optimised for the detection of astrophysical neutrinos with energies above <span><math><mo>∼</mo></math></span>1 TeV. In this work, using Monte Carlo simulations including all-flavour neutrinos, the integrated and differential sensitivities for KM3NeT/ARCA are presented considering the case of a diffuse neutrino flux as well as extended and point-like neutrino sources. This analysis is applied to Starburst Galaxies demonstrating that the detector has the capability of tracing TeV neutrinos from these sources. Remarkably, after eight years, a hard power-law spectrum from the nearby Small Magellanic Cloud can be constrained. The sensitivity and discovery potential for NGC 1068 is also evaluated showing that KM3NeT/ARCA will discriminate between different astrophysical components of the measured neutrino flux after 3 years of data taking.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"162 ","pages":"Article 102990"},"PeriodicalIF":3.5,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0927650524000677/pdfft?md5=2f59c6bfde7fbc3aa2e3711ee9f85123&pid=1-s2.0-S0927650524000677-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141194993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Schwarzschild black hole surrounded by a cavity and phase transition in the non-commutative gauge theory of gravity","authors":"Abdellah Touati,&nbsp;Slimane Zaim","doi":"10.1016/j.astropartphys.2024.102988","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102988","url":null,"abstract":"<div><p>In this work, we investigate the phase transition of the Schwarzschild black hole (SBH) inside an isothermal spherical cavity in the context of the non-commutative (NC) gauge theory of gravity, by using the Seiberg–Witten (SW) map and the star product. Firstly, we compute the NC correction to the Hawking temperature and derive the logarithmic correction to the entropy, then we derive the local temperature and local energy of NC SBH in isothermal cavity. Our results show that the non-commutativity removes the commutative divergence behavior of temperature, and prevents the SBH from the complete evaporation, which leads to a remnant black hole, and this geometry has predicted a minimal length in the order of Planck scale <span><math><mrow><mi>Θ</mi><mo>∼</mo><msub><mrow><mi>l</mi></mrow><mrow><mi>p</mi><mi>l</mi><mi>a</mi><mi>n</mi><mi>c</mi><mi>k</mi></mrow></msub></mrow></math></span>. Therefore, the thermodynamic stability and phase transition is studied by analyzing the behavior of the local heat capacity and the Helmholtz free energy in the NC spacetime, where the results show that, the NC SBH has a two second-order phase transition and one first-order phase transition, with two Hawking–Page phase transition in the NC gauge theory.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102988"},"PeriodicalIF":3.5,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141084275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atmospheric muons and their variations with temperature","authors":"S. Verpoest ,&nbsp;D. Soldin ,&nbsp;P. Desiati","doi":"10.1016/j.astropartphys.2024.102985","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102985","url":null,"abstract":"<div><p>Seasonal variations of atmospheric muons are traditionally interpreted in terms of an effective temperature that relates the atmospheric temperature profile at a given time to the dependence of muon production on atmospheric depth. This paper aims to review and generalize the treatment of muon production and effective temperature that has been used to interpret seasonal variations of atmospheric muons by many experiments. The formalism is developed both in integral form – for application to compact detectors at a fixed depth that record all muons with <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>μ</mi></mrow></msub><mo>&gt;</mo><msubsup><mrow><mi>E</mi></mrow><mrow><mi>μ</mi></mrow><mrow><mi>min</mi></mrow></msubsup></mrow></math></span> – and in differential form — for application to extended detectors like IceCube, KM3NeT, and Baikal-GVD, where the rates are proportional to energy-dependent effective areas.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102985"},"PeriodicalIF":3.5,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140948741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Loaded layer-cake model for cosmic ray interaction around exploding super-giant stars making black holes","authors":"M.L. Allen ,&nbsp;P.L. Biermann ,&nbsp;A. Chieffi ,&nbsp;D. Frekers ,&nbsp;L.Á. Gergely ,&nbsp;B. Harms ,&nbsp;I. Jaroschewski ,&nbsp;P.S. Joshi ,&nbsp;P.P. Kronberg ,&nbsp;E. Kun ,&nbsp;A. Meli ,&nbsp;E.-S. Seo ,&nbsp;T. Stanev","doi":"10.1016/j.astropartphys.2024.102976","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102976","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The experiment AMS on the International Space-Station has produced accurate cosmic ray spectra for many chemical elements, both primaries like He, C, O, Fe, other cosmic ray (CR) primaries like Ne, Mg, and Si, secondaries like Li, Be, B, and of mixed provenance, like N, Na, and Al. The AMS spectra demonstrate that interaction is seriously diminishing fluxes up to a rigidity of about 100 GV, and so the existing models for CR interaction have to be re-examined. Based on earlier well-established ideas a model is proposed here that focusses on the cosmic ray interaction first in the wind shock shell of super giant stars, when the supernova driven shock races through, and second in the OB-Superbubble surrounding the SN: These stars include both red super-giant stars and blue super-giant stars; both produce black holes in their explosion, and drive winds and jets with electric currents. Variability of these winds or jets gives rise to temporary electric fields, as has recently been demonstrated, and discharge (so lightning) acceleration gives steep spectra, with synchrotron losses to &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; in momentum &lt;span&gt;&lt;math&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;; these spectra are typically observed in both Galactic and some extragalactic radio filaments. Analogous hadron spectra &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; excite a flat spectrum of magnetic irregularities in the bubble zone, which in turn yields a steep dependence of residence time versus energy, with power &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;5&lt;/mn&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. This spectrum is indicated by the AMS data and appears to be required to explain the CR spectra below 100 GV. The emphasis in this paper is to work out the interaction of the freshly accelerated cosmic ray particles. In the model presented here the interaction is derived as a function of time, and then integrated, or developed to long times. The model gives a rigidity dependence of the secondary/primary ratio of slope &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; as well as the strong reduction of the primary fluxes below a rigidity of about 100 GV, relative to a power-law injection spectrum, with slope &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The two key aspects based on blue super-giant stars and a magnetic irregularity spectrum in the bubble zone given by lightning are (i) a much larger column of interaction, allowed because of heavy element enrichment of the interaction zone, and (ii) even He, C, and O may have a small secondary contribution, as the difference to the Fe spectrum suggests; this small secondary component is visible in the &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;He/&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102976"},"PeriodicalIF":3.5,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140879410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Some inflationary models under the light of Planck 2018 results","authors":"Daniel Pozo ,&nbsp;Jordan Zambrano ,&nbsp;Ismael Villegas ,&nbsp;Rafael Hernández–Jiménez ,&nbsp;Clara Rojas","doi":"10.1016/j.astropartphys.2024.102977","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102977","url":null,"abstract":"<div><p>In this work we study four well-known inflationary scenarios that are reported by the most recent Planck observations: Natural inflation, Hilltop quartic inflation, Starobinsky inflationary model, and Large field power-law potentials <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>ϕ</mi><mo>)</mo></mrow><mo>∼</mo><msup><mrow><mi>ϕ</mi></mrow><mrow><mi>p</mi></mrow></msup></mrow></math></span>, considering <span><math><mrow><mi>p</mi><mo>=</mo><mfrac><mrow><mn>2</mn></mrow><mrow><mn>3</mn></mrow></mfrac><mo>,</mo><mfrac><mrow><mn>4</mn></mrow><mrow><mn>3</mn></mrow></mfrac></mrow></math></span>. The analysis is done using both the slow-roll approximation and the numerical solution to the background and perturbation equations. We show that the numerical solution improved the precision of these models with respect to the contour plot <span><math><mi>r</mi></math></span> vs. <span><math><msub><mrow><mi>n</mi></mrow><mrow><mi>S</mi></mrow></msub></math></span>, having a lower <span><math><mi>r</mi></math></span> in each model compared to the value calculated from the slow-roll approximation.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"161 ","pages":"Article 102977"},"PeriodicalIF":3.5,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140816300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On possible traversable wormhole solutions supported by Karmarkar condition in R2−gravity within the f(R,T)−formalism","authors":"Abdelghani Errehymy ,&nbsp;S.K. Maurya ,&nbsp;Gabriel-Eduard Vîlcu ,&nbsp;Meraj Ali Khan ,&nbsp;Mohammed Daoud","doi":"10.1016/j.astropartphys.2024.102972","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102972","url":null,"abstract":"<div><p>In their seminal work, Morris and Thorne (1988) introduced the concept of traversable wormholes (WHs), which are geometric structures serving as bridges to connect two distinct spacetimes or different points within the same spacetime. The properties of these WHs are determined by the choice of the shape function. Extensive research has been conducted in the literature on WHs within modified theories of gravity, considering various types of shape functions. In this paper, we focus on deriving the simplest solutions for traversable WHs within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity. Our specific focus lies on the functional form <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>R</mi><mo>+</mo><mi>α</mi><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>+</mo><mi>λ</mi><mi>T</mi></mrow></math></span>, where <span><math><mi>R</mi></math></span> represents the Ricci scalar and <span><math><mi>T</mi></math></span> denotes the trace of the energy–momentum tensor. By incorporating quadratic geometric and linear material corrections, we demonstrate that the matter content of WHs can obediently conform to the energy conditions (ECs). This study significantly advances our understanding of WHs within the context of modified gravity. Our findings shed new light on the behavior and properties of WHs, highlighting their compatibility with the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity framework. By unveiling the ability of WHs to adhere to ECs through the inclusion of geometric and material corrections, we provide groundbreaking insights into these intriguing objects. Overall, our research contributes to the broader field of gravitational physics by presenting a unique perspective on WH modeling. By exploring WHs within the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> gravity framework and demonstrating their conformity to ECs, we expand our knowledge of these fascinating structures and pave the way for further investigations in this area.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"160 ","pages":"Article 102972"},"PeriodicalIF":3.5,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140557892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of jet-caused 12-year optical periodicity of blazar OJ 287","authors":"Gorbachev M.A.,&nbsp;Butuzova M.S.,&nbsp;Nazarov S.V.,&nbsp;Zhovtan A.V.","doi":"10.1016/j.astropartphys.2024.102965","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102965","url":null,"abstract":"<div><p>Blazar OJ 287 is one of the first candidates with the assumed compact system of two supermassive black holes in the center. Orbital interaction in this system has been used to explain the for over a century light curve, in which optical flares are repeated with a quasi-period of 12 years and have almost yearly duration. The absence of the predicted flare in 2022 casts doubt on the dominant model of a close system of binary black holes. The detection of optical flares outside the 12-year period and their interpretation by processes in the jet complicates the construction of a complete picture of the blazar OJ 287 optical variability. Here, we analyze the 50-year evolution of the optical spectrum and prove that the changing coefficient of relativistic boosting of two regions in a helical jet subject to an age-long orientation change forms all flares. Our findings indicate the absence of the compact binary black hole system and the impossibility of drawing reliable conclusions about the central engine of active galactic nuclei based only on the quasi-periodic brightness variability of blazars.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"160 ","pages":"Article 102965"},"PeriodicalIF":3.5,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140537132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thomas K. Gaisser, a pioneer of particle astrophysics","authors":"Francis Halzen ,&nbsp;Paolo Lipari","doi":"10.1016/j.astropartphys.2024.102963","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102963","url":null,"abstract":"<div><p>We describe the pioneering contributions of Thomas K. Gaisser to the birth and development of particle astrophysics, a new field of research at the intersection of cosmic ray physics, astronomy, astrophysics, and particle physics that has emerged in the last few decades. We will especially focus on his studies of natural beams of neutrinos: those generated by the interactions of cosmic rays in the Earth’s atmosphere and those emitted by astrophysical sources. Tom actively participated in the discovery of these cosmic neutrinos as well. His contributions also extend to gamma-ray astronomy, the study of the cosmic ray spectra and composition, and the modeling of cosmic ray interactions in the atmosphere and in astrophysical environments. Tom invariably focused his research on the theoretical and phenomenological problems of greatest interest at the time, producing frameworks that transparently interpreted often complex data. These studies have been very influential and have shaped the development of the field.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"159 ","pages":"Article 102963"},"PeriodicalIF":3.5,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140320808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}