Astroparticle Physics最新文献

{"title":"The exact solution approach to warm inflation","authors":"Oem Trivedi","doi":"10.1016/j.astropartphys.2024.102951","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102951","url":null,"abstract":"<div><p>The theory of cosmic inflation has received a great amount of deserved attention in recent years due to it’s stunning predictions about the early universe. Alongside the usual cold inflation paradigm, warm inflation has garnered a huge amount of interest in modern inflationary studies. It’s peculiar features and specifically different predictions from cold inflation have led to a substantial amount of literature about it. Various modified cosmological scenarios have also been studied in the warm inflationary regime. In this work, we introduce the exact solution approach for warm inflation. This approach allows one to directly study warm inflationary regime in a variety of modified cosmological scenarios. We begin by outlining our method and show that it generalizes the modified Friedmann approach of Del Campo, and reduces to the well known Hamilton–Jacobi formalism for inflation in particular limits. We also find the perturbation spectra for cosmological and tensor perturbations in the early universe, and then apply our method to study warm inflation in a Tsallis entropy modified Friedmann universe. We end our paper with some concluding remarks on the domain of applicability of our work.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102951"},"PeriodicalIF":3.5,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140024007","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":"Analyses of continuous measurements of cosmic ray induced-neutrons spectra at the Concordia Antarctic Station from 2016 to 2024","authors":"G. Hubert","doi":"10.1016/j.astropartphys.2024.102949","DOIUrl":"10.1016/j.astropartphys.2024.102949","url":null,"abstract":"<div><p>This paper presents analyses of cosmic-ray-induced neutron measurements spanning from 2016 to 2023 at the Concordia Antarctic high-altitude station. Environmental and systematic effects are meticulously considered in both long-term and short-term perspectives. The study delves into space weather cases, focusing on solar events in September 2017 and October 2021, along with a specific examination of the impact of the Atmospheric River in March 2022. The paper explores the valuable contribution of modeling to data analyses, particularly its capacity to infer solar modulation from neutron spectra. All analyses integrate modulations of the neutron spectrum, with a specific emphasis on short-term events, representing the principal contribution of the spectral measurements.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"159 ","pages":"Article 102949"},"PeriodicalIF":3.5,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140008178","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":"The performance of generalised Davies–Cotton optical systems with infinitesimal mirror facets","authors":"S. Fegan","doi":"10.1016/j.astropartphys.2024.102948","DOIUrl":"10.1016/j.astropartphys.2024.102948","url":null,"abstract":"<div><p>This paper presents Taylor expansions for the imaging and timing characteristics of spherical optical systems with infinitesimal mirror facets, sometimes referred to as “modified Davies–Cotton” telescopes. Such a system comprises a discontinuous spherical mirror surface whose curvature radius is different from its focal length, and whose mirrors are aligned to suppress spherical aberration. Configurations that range between two “optima” are, one of which minimises tangential comatic aberration and the other that minimises timing dispersion.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102948"},"PeriodicalIF":3.5,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0927650524000252/pdfft?md5=c1fa59dd4cd5a9fd0e314cec6e91052e&pid=1-s2.0-S0927650524000252-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139924579","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":"The cosmic ray energetics and mass for the international space station (ISS-CREAM) instrument","authors":"Y.S. Yoon ,&nbsp;Y. Amare ,&nbsp;D. Angelaszek ,&nbsp;N. Anthony ,&nbsp;K. Cheryian ,&nbsp;G.H. Choi ,&nbsp;M. Copley ,&nbsp;S. Coutu ,&nbsp;L. Derome ,&nbsp;L. Eraud ,&nbsp;L. Hagenau ,&nbsp;J.H. Han ,&nbsp;H.G. Huh ,&nbsp;Y.S. Hwang ,&nbsp;H.J. Hyun ,&nbsp;S. Im ,&nbsp;H.B. Jeon ,&nbsp;J.A. Jeon ,&nbsp;S. Jeong ,&nbsp;S.C. Kang ,&nbsp;H.G. Zhang","doi":"10.1016/j.astropartphys.2024.102947","DOIUrl":"10.1016/j.astropartphys.2024.102947","url":null,"abstract":"<div><p>The ISS-CREAM instrument is the modified version of the Cosmic Ray Energetics And Mass (CREAM) experiment, which was flown on balloons multiple times over Antarctica and later installed on the International Space Station (ISS). Its primary objective is to measure the energy spectra of individual cosmic-ray elements for the charge range of <em>Z</em> = 1 to <em>Z</em> = 26, in the energy range of ∼ 10¹² to ∼ 10¹⁵ eV. The instrument comprises a tungsten/scintillator calorimeter and a pixelated silicon charge detector as primary detectors to determine the energy and charge of cosmic rays. Additionally, it includes top and bottom scintillator counting detectors and a boronated scintillator detector to differentiate between electrons and hadrons for multi-TeV electron measurements. The ISS-CREAM instrument was installed on the ISS in August 2017 and operated until February 2019. This paper provides an overview of the instrument, focusing on its detectors, trigger systems, common electronics, and power systems. The paper highlights the modifications made to these components to optimize their performance for ISS operations.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102947"},"PeriodicalIF":3.5,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139874753","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":"Machine learning-based discrimination of bulk and surface events of germanium detectors for light dark matter detection","authors":"P. Zhang ,&nbsp;H. Ma ,&nbsp;L. Yang ,&nbsp;Z. Zeng ,&nbsp;Q. Yue ,&nbsp;J. Cheng","doi":"10.1016/j.astropartphys.2024.102946","DOIUrl":"10.1016/j.astropartphys.2024.102946","url":null,"abstract":"<div><p>Surface events that exhibit incomplete charge collection are an essential background source in the light dark matter detection experiments with p-type point-contact germanium detectors. We propose a machine learning-based algorithm to identify bulk and surface events according to their pulse shape features. We construct the training and test set with part of the <span><math><mi>γ</mi></math></span>-source calibration data and use the rising edge of the waveform as the model input. This method is verified with the test set and another part of the <span><math><mi>γ</mi></math></span>-source calibration data. Results show that this method performs well on both datasets, and presents robustness against the bulk events’ proportion and the dataset size. Compared with the previous approach, the uncertainty is reduced by 16% near the energy threshold on the physics data of CDEX-1B. In addition, the key pattern identified in the waveform is verified to be consistent with its physical nature by digging into this algorithm.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102946"},"PeriodicalIF":3.5,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139832980","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":"Alpha backgrounds in NaI(Tl) crystals of COSINE-100","authors":"G. Adhikari ,&nbsp;N. Carlin ,&nbsp;D.F.F.S. Cavalcante ,&nbsp;J.Y. Cho ,&nbsp;J.J. Choi ,&nbsp;S. Choi ,&nbsp;A.C. Ezeribe ,&nbsp;L.E. França ,&nbsp;C. Ha ,&nbsp;I.S. Hahn ,&nbsp;S.J. Hollick ,&nbsp;E.J. Jeon ,&nbsp;H.W. Joo ,&nbsp;W.G. Kang ,&nbsp;M. Kauer ,&nbsp;B.H. Kim ,&nbsp;H.J. Kim ,&nbsp;J. Kim ,&nbsp;K.W. Kim ,&nbsp;S.H. Kim ,&nbsp;G.H. Yu","doi":"10.1016/j.astropartphys.2024.102945","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102945","url":null,"abstract":"<div><p>COSINE-100 is a dark matter direct detection experiment with 106<!--> <!-->kg NaI(Tl) as the target material. ²¹⁰Pb and daughter isotopes are a dominant background in the WIMP region of interest and are detected via <span><math><mi>β</mi></math></span> decay and <span><math><mi>α</mi></math></span> decay. Analysis of the <span><math><mi>α</mi></math></span> channel complements the background model as observed in the <span><math><mi>β</mi></math></span>/<span><math><mi>γ</mi></math></span> channel. We present the measurement of the quenching factors and Monte Carlo simulation results and activity quantification of the <span><math><mi>α</mi></math></span> decay components of the COSINE-100 NaI(Tl) crystals. The data strongly indicate that the <span><math><mi>α</mi></math></span> decays probabilistically undergo two possible quenching factors but require further investigation. The fitted results are consistent with independent measurements and improve the overall understanding of the COSINE-100 backgrounds. Furthermore, the half-life of ²¹⁶Po has been measured to be <span><math><mrow><mn>143</mn><mo>.</mo><mn>4</mn><mspace></mspace><mo>±</mo><mspace></mspace><mn>1</mn><mo>.</mo><mn>2</mn></mrow></math></span> <!--> <!-->ms, which is consistent with and more precise than most current measurements.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102945"},"PeriodicalIF":3.5,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139726414","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":"A novel energy reconstruction method for the MAGIC stereoscopic observation","authors":"Kazuma Ishio ,&nbsp;David Paneque","doi":"10.1016/j.astropartphys.2024.102937","DOIUrl":"https://doi.org/10.1016/j.astropartphys.2024.102937","url":null,"abstract":"<div><p>We report the successful development of a novel methodology of energy reconstruction for very high energy gamma rays detected with Imaging Atmospheric Cherenkov Telescopes (IACTs). This methodology, based on the machine learning algorithm Random Forest, and named RF-Erec, has been adjusted for being used with data from the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) stereo telescope system, which is a worldwide leading instrument for gamma-ray astronomy in the energy range from about 20<!--> <!-->GeV to beyond 100<!--> <!-->TeV.</p><p>The RF-Erec has been evaluated using different realistic scenarios with Monte Carlo simulated data and real observations from the Crab Nebula (the standard candle for the VHE gamma-ray community). This new methodology has been validated by the MAGIC software board, and it is implemented and ready-to-use in the MAGIC Analysis and Reconstruction Software (MARS). This new methodology, validated by the MAGIC software board, has been implemented and is ready for use in the MAGIC Analysis and Reconstruction Software (MARS). We demonstrate that, in comparison to the previous energy reconstruction methodology for MAGIC data, which relied on Look-Up-Tables (LUTs- Erec) and has been utilized in over 100 scientific publications over the last decade, RF-Erec significantly enhances the energy reconstruction of gamma rays. This improvement extends the capabilities of the MAGIC telescopes.</p><p>Specifically, when quantifying the energy resolution with the width of a Gaussian fitted to the error distribution (<em>resolution-</em><span><math><mi>σ</mi></math></span>), the RF-Erec energy resolution-<span><math><mi>σ</mi></math></span> is 20% at 100 GeV and 11% above 1 TeV for Zenith distances (Zd) below 35 degrees, while it is 20% at 1<!--> <!-->TeV and 13% above 10<!--> <!-->TeV for Zd above 55 degrees. For a wide range of the observable energies, the improvement of energy resolution-<span><math><mi>σ</mi></math></span>, compared to LUTs-Erec, reaches roughly a factor of two, and the improvement is even larger for high Zd observations. Differently to many other works in the literature, our evaluation also considers the energy dispersion and the actual energy migration of events, where RF-Erec improves the performance of LUTs-Erec by factors of a few. The manuscript also demonstrates the importance of energy reconstruction methods with a small energy migration in order to prevent the appearance of artificial spectral features. These artifacts are particularly important at the high end of the gamma-ray spectra, where a few extra high-energy photons could have dramatic consequences for studies related to the EBL attenuation, Lorentz invariance violation, or searches for Axion-like-particles.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102937"},"PeriodicalIF":3.5,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139907967","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":"The expected potential of hadronic PeVatron searches with spectral γ-ray data from the Southern Wide-field Gamma-ray Observatory","authors":"Ekrem Oğuzhan Angüner ,&nbsp;Tülün Ergin","doi":"10.1016/j.astropartphys.2024.102936","DOIUrl":"10.1016/j.astropartphys.2024.102936","url":null,"abstract":"<div><p>The presence of a spectral softening, occurring at <span><math><mo>∼</mo></math></span>3 PeV energies, seen in the local cosmic-ray energy spectrum provides an evidence that our Galaxy hosts astrophysical objects, known as ’hadronic PeVatrons’, that are capable of accelerating hadrons to PeV energies and above. Recent results from ground-based particle detector array experiments have provided conclusive evidence that these facilities are essential to explore the ultra-high-energy (UHE, E<span><math><mrow><mo>&gt;</mo><mn>100</mn></mrow></math></span> TeV) <span><math><mi>γ</mi></math></span>-ray domain and pinpoint the location of PeVatrons in the Galaxy. The Southern Wide-field Gamma-ray Observatory (SWGO) is proposed next-generation ground-based extensive air shower observatory planned for construction in the Southern Hemisphere, which holds great scientific potential for UHE observations. In this study, we investigate the expected potential of SWGO to search for hadronic PeVatrons, based on the publicly available preliminary SWGO straw-man instrument response functions (IRFs). By using these straw-man IRFs, it can be shown that the SWGO detection of <span><math><mi>γ</mi></math></span>-ray spectral cutoffs between 30 TeV and 100 TeV, at a 95% confidence level, is possible for faint <span><math><mi>γ</mi></math></span>-ray sources of <span><math><mo>∼</mo></math></span>5 mCrab given that the spectral index is hard (<span><math><mrow><mi>Γ</mi><mo>≲</mo></mrow></math></span> 2.0), while spectral cutoffs from softer sources with <span><math><mrow><mi>Γ</mi><mo>≅</mo></mrow></math></span>2.3 can be detected for sources brighter than <span><math><mrow><mo>∼</mo><mn>11</mn><mo>−</mo></mrow></math></span>12 mCrab. The reconstructed SWGO PeVatron detection maps demonstrate that the future SWGO experiment can probe large parts of the investigated PeVatron parameter space, providing a robust detection and/or rejection of presence of spectral signatures associated with hadronic PeVatrons. A dedicated study on the promising Southern-sky PeVatron candidates, the Galactic Center region, Westerlund 1, HESS J1702<span><math><mo>−</mo></math></span>420 and HESS J1641<span><math><mo>−</mo></math></span>463, shows that the SWGO will have a great potential to confirm or exclude PeVatron nature of these candidate sources at a robust significance level after 5-years of observation. In addition, it is shown that controlling systematic errors will be necessary to reach full potential of the SWGO experiment for PeVatron searches.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102936"},"PeriodicalIF":3.5,"publicationDate":"2024-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139678316","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":"Adaptive kernel density estimation for improved sky map computation in gamma-ray astronomy","authors":"M. Holler,&nbsp;T. Mitterdorfer,&nbsp;S. Panny","doi":"10.1016/j.astropartphys.2024.102934","DOIUrl":"10.1016/j.astropartphys.2024.102934","url":null,"abstract":"<div><p>We introduce an alternative method for the calculation of sky maps from data taken with gamma-ray telescopes. In contrast to the established method of smoothing the 2D histogram of reconstructed event directions with a static kernel, we apply a Kernel Density Estimation (KDE) where the kernel size of each gamma-ray candidate is related to its estimated direction uncertainty. Exploiting this additional information implies a gain in resulting image quality, which is validated using both simulations and data. For the tested simulation and analysis configuration, the achieved improvement can only be matched with the classical approach by removing events with lower reconstruction quality, reducing the data set by a considerable amount.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102934"},"PeriodicalIF":3.5,"publicationDate":"2024-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0927650524000112/pdfft?md5=a177a043ba4e7016e034a0aa302bd60a&pid=1-s2.0-S0927650524000112-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139662761","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":"Exploring one giga electronvolt cosmic gamma rays with a Cherenkov plenoscope capable of recording atmospheric light fields, Part 1: Optics","authors":"Sebastian Achim Mueller ,&nbsp;Spyridon Daglas ,&nbsp;Axel Arbet Engels ,&nbsp;Max Ludwig Ahnen ,&nbsp;Dominik Neise ,&nbsp;Adrian Egger ,&nbsp;Eleni Chatzi ,&nbsp;Adrian Biland ,&nbsp;Werner Hofmann","doi":"10.1016/j.astropartphys.2024.102933","DOIUrl":"10.1016/j.astropartphys.2024.102933","url":null,"abstract":"<div><p>Detecting cosmic gamma rays at high rates is the key to time-resolve the acceleration of particles within some of the most powerful events in the universe. Time-resolving the emission of gamma rays from merging celestial bodies, apparently random bursts of gamma rays, recurring novas in binary systems, flaring jets from active galactic nuclei, clocking pulsars, and many more became a critical contribution to astronomy. For good timing on account of high rates, we would ideally collect the naturally more abundant, low energetic gamma rays in the domain of one giga electronvolt in large areas. Satellites detect low energetic gamma rays but only in small collecting areas. Cherenkov telescopes have large collecting areas but can only detect the rare, high energetic gamma rays. To detect gamma rays with lower energies, Cherenkov-telescopes need to increase in precision and size. But when we push the concept of the –far/tele– seeing Cherenkov telescope accordingly, the telescope’s physical limits show more clearly. The narrower depth-of-field of larger mirrors, the aberrations of mirrors, and the deformations of mirrors and mechanics all blur the telescope’s image. To overcome these limits, we propose to record the –full/plenum– Cherenkov-light field of an atmospheric shower, i.e. recording the directions and impacts of each individual Cherenkov photon simultaneously, with a novel class of instrument. This novel Cherenkov plenoscope can turn a narrow depth-of-field into the perception of depth, can compensate aberrations, and can tolerate deformations. We design a Cherenkov plenoscope to explore timing by detecting low energetic gamma rays in large areas.</p></div>","PeriodicalId":55439,"journal":{"name":"Astroparticle Physics","volume":"158 ","pages":"Article 102933"},"PeriodicalIF":3.5,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0927650524000100/pdfft?md5=ec6ab2fc414cb49a2e28c4074cfd3544&pid=1-s2.0-S0927650524000100-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139645215","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}