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Understanding ADC variation by fat content effect using a dual-function MRI phantom

European Radiology Experimental 2024年第1期8卷 19页

作者： Liu, Yi-Jui Tsai, Tung-Sheng Li, Ya-Hui Peng, Jo-Hua Chang, Hing-Chiu Peng, Hsu-Hsia Lee, Ying-Chieh Lee, Tung-Yang Liou, Chang-Hsien Lin, Tz-Feng Chew, Fatt-Yang Chou, Ruey-Hwang Juan, Chun-Jung Department of Automatic Control Engineering Feng Chia University Taichung Taiwan Ph.D. Program in Electrical and Communication Engineering Feng Chia University Taichung Taiwan Department of Medical Imaging China Medical University Hsinchu Hospital 199 Sec. 1 Xinglong Rd. Hsinchu County Zhubei City 302 Taiwan Department of Biomedical Engineering and Environmental Sciences National Tsing Hua University Hsinchu Taiwan Department of Biomedical Engineering Chinese University of Hong Kong Hong Kong Master’s Program of Biomedical Informatics and Biomedical Engineering Feng Chia University Taichung Taiwan Cheng Ching Hospital Taichung Taiwan Institute of Nuclear Engineering and Science National Tsing Hua University Hsinchu Taiwan Department of Fiber and Composite Materials Feng Chia University Taichung Taiwan Department of Medical Imaging China Medical University Hospital Taichung Taiwan Department of Radiology School of Medicine China Medical University Taichung Taiwan Graduate Institute of Biomedical Sciences China Medical University Taichung 406 Taiwan Center for Molecular Medicine China Medical University Hospital Taichung Taiwan Department of Medical Laboratory and Biotechnology Asia University Taichung Taiwan

Background: A dual-function phantom designed to quantify the apparent diffusion coefficient (ADC) in different fat contents (FCs) and glass bead densities (GBDs) to simulate the human tissues has not been documented yet. We propose a dual-function phantom to quantify the FC and to measure the ADC at different FCs and different GBDs. Methods: A fat-containing diffusion phantom comprised by 30 glass-bead-containing fat-water emulsions consisting of six different FCs (0, 10, 20, 30, 40, and 50%) multiplied by five different GBDs (0, 0.1, 0.25, 0.5, and 1.0 g/50 mL). The FC and ADC were measured by the “iterative decomposition of water and fat with echo asymmetry and least squares estimation-IQ,” IDEAL-IQ, and single-shot echo-planar diffusion-weighted imaging, SS-EP-DWI, sequences, respectively. Linear regression analysis was used to evaluate the relationship among the fat fraction (FF) measured by IDEAL-IQ, GBD, and ADC. Results: The ADC was significantly, negatively, and linearly associated with the FF (the linear slope ranged from -0.005 to -0.017, R² = 0.925 to 0.986, all p < 0.001). The slope of the linear relationship between the ADC and the FF, however, varied among different GBDs (the higher the GBD, the lower the slope). ADCs among emulsions across different GBDs and FFs were overlapped. Emulsions with low GBDs plus high FFs shared a same lower ADC range with those with median or high GBDs plus median or lower FFs. Conclusions: A novel dual-function phantom simulating the human tissues allowed to quantify the influence of FC and GBD on ADC. Relevance statement: The study developed an innovative dual-function MRI phantom to explore the impact of FC on ADC variation that can affect clinical results. The results revealed the superimposed effect on FF and GBD density on ADC measurements. Key points: • A dual-function phantom made of glass bead density (GBD) and fat fraction (FF) emulsion has been developed. • Apparent diffusion coefficient (ADC) values

关键词： Adipose tissue Diffusion magnetic resonance imaging Phantoms (imaging) Quality assurance (healthcare) Quality control

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Enhancing Herbicide Adsorption in Low-Fertility Soil Using Sugarcane Biochar: Insights from Imazapic Dynamics

SSRN

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SSRN 2024年

作者： Lopes, Jéssica Rafaelly Almeida Mendonça, Zabele Laís Lyra da Silva, João Paulo Siqueira Amaral, Ademir Netto, André Maciel Federal Rural University of Pernambuco Graduate Program in Environmental Engineering Rua Dom Manuel de Medeiros s/n Dois Irmãos PE 52171-900 Brazil Federal University of Pernambuco Department of Nuclear Energy Av. Prof. Luiz Freire 1000 Curado PE 50740-545 Brazil

Biochar amendment has emerged as a potential solution for preventing, remediating, and mitigating agricultural compound pollution. This groundbreaking technique not only improves crucial soil properties like porosity, water retention capacity, cation exchange capacity, and pH, but also intricately impacts the interaction and retention mechanisms of polluting molecules. In this study, we investigate the dynamic of the herbicide Imazapic when subjected to applying pyrolyzed biochars, specifically at temperatures of 300 and 500°C, within the context of a low-fertility soil characterized as dystrophic Yellow Ultisol (YUd) in a sugarcane cultivation area in Igarassu-PE, Brazil. The biochars were produced from sugarcane bagasse by pyrolysis process in a muffle furnace. In laboratory conditions, with saturated soil columns under steady-state, analyses of the mechanisms involved in interaction and transport and determining hydrodispersive parameters for Imazapic were performed by the two-site nonequilibrium transport model using the CXTFIT 2.0 program. Samples of YUd soil amended with biochar pyrolyzed at 300°C presented a negligible interaction with Imazapic. However, adding biochar pyrolyzed at 500°C (BC500) to the soil samples enhanced the adsorption coefficient and improved the interaction with Imazapic. This research points out that biochar produced from agricultural waste biomass, such as sugarcane bagasse specifically pyrolyzed at 500°C, offers a potential means to adsorb herbicides, reducing their leaching to deeper layers of the amended soils and the risk of groundwater contamination and potential environmental negative impacts. © 2024, The Authors. All rights reserved.

关键词： Leaching

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Multimodal Spatial Attention Network for Automatic Head and Neck Tumor Segmentation in FDG-PET and CT Images 1

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2nd 3D Head and Neck Tumor Segmentation in PET/CT Challenge, HECKTOR 2021, held in conjunction with 24th International Conference on Medical Image Computing and Computer-Assisted Intervention, MICCAI 2021

作者： Cho, Minjeong Choi, Yujin Hwang, Donghwi Yie, Si Young Kim, Hanvit Lee, Jae Sung School of Electrical and Electronics Engineering Chung-Ang University Seoul06974 Korea Republic of Department of Biomedical Engineering Kyunghee University College of Electronics and Information 1732 Deogyeong-daero Giheung-gu Gyeonggi-do Yongin-si Korea Republic of Department of Nuclear Medicine Seoul National University College of Medicine Seoul03080 Korea Republic of Department of Biomedical Sciences Seoul National University College of Medicine Seoul03080 Korea Republic of Interdisciplinary Program in Bioengineering Seoul National University Graduate School Seoul Korea Republic of Integrated Major in Innovative Medical Science Seoul National University Graduate School Seoul Korea Republic of Ulsan Korea Republic of Artificial Intelligence Institute Seoul National University Seoul08826 Korea Republic of Brightonix Imaging Inc. Seoul04782 Korea Republic of

ISBN: (数字)9783030982539

ISBN: (纸本)9783030982522

Quantitative positron emission tomography/computed tomography (PET/CT), owing to the functional metabolic information and anatomical information of the human body that it presents, is useful to achieve accurate tumor delineation. However, manual annotation of a Volume Of Interest (VOI) is a labor-intensive and time-consuming task. In this study, we automatically segmented the Head and Neck (H&N) primary tumor in combined PET/CT images. Herein, we propose a convolutional neural network named Multimodal Spatial Attention Network (MSA-Net), supplemented with a Spatial Attention Module (SAM), which uses a PET image as an input. We evaluated this model on the MICCAI 2021 HEad and neCK TumOR (HECKTOR) segmentation challenge dataset. Our method delivered a competitive cross-validation efficiency, with Dice Similarity Coefficient (DSC) 0.757, precision 0.788, and recall 0.785. When we tested out method on test dataset, we achieved an average DSC and Hausdorff Distance at 95% (HD95) of 0.766 and 3.155 respectively. Our team name is ‘Heck_Uihak’. © 2022, Springer Nature Switzerland AG.

关键词： Tumors

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Do Sites Benefit Equally from Distributed Learning in Medical Image Analysis? 2nd

Do Sites Benefit Equally from Distributed Learning in Medi...

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2nd International Workshop on Fairness of AI in Medical Imaging, FAIMI 2024, and 3rd International Workshop on Ethical and Philosophical Issues in Medical Imaging, EPIMI 2024, Held in Conjunction with the International Conference on Medical Image Computing and Computer Assisted Interventions, MICCAI 2024

作者： Souza, Raissa Stanley, Emma A. M. Camicioli, Richard Monchi, Oury Ismail, Zahinoor Wilms, Matthias Forkert, Nils D. Department of Radiology Cumming School of Medicine University of Calgary Calgary Canada Hotchkiss Brain Institute University of Calgary Calgary Canada Biomedical Engineering Graduate Program University of Calgary Calgary Canada Alberta Children’s Hospital Research Institute University of Calgary Calgary Canada University of Alberta Edmonton Canada Department of Radiology Radio-oncology and Nuclear Medicine Université de Montréal Montréal Canada Centre de Recherche Institut Universitaire de Gériatrie de Montréal Montréal Canada Department of Clinical Neurosciences Cumming School of Medicine University of Calgary Calgary Canada Department of Psychiatry University of Calgary Calgary Canada Clinical and Biomedical Sciences Faculty of Health and Life Sciences University of Exeter Exeter United Kingdom Department of Pediatrics University of Calgary Calgary Canada Department of Community Health Sciences University of Calgary Calgary Canada

ISBN: (纸本)9783031727863

Artificial intelligence (AI) has the potential to make medical image analysis more accessible to healthcare institutions worldwide. However, when trained on multi-site datasets, models may excel with data from certain institutions but struggle with others, even when exposed to their training data. This emphasizes the importance of investigating whether all sites benefit from AI models, especially within distributed learning setups. Distributed learning methods allow access to broader and more diverse datasets from multiple sites during training. In this context, the travelling model (TM) paradigm has demonstrated superior performance in limited data scenarios, making it particularly relevant in low-resource settings. This work investigates whether all sites can benefit from TM development and identifies the factors influencing performance disparities. Specifically, a Parkinson’s disease (PD) database comprising 1,817 neuroimaging datasets from 83 different sites is utilized to investigate how site-specific and participant-specific factors influence the performance of TM in classifying PD. Therefore, we analyze the false positive rate (FPR) and false negative rate (FNR) to identify the characteristics contributing to misdiagnosis. Our findings reveal disparities in benefits across sites, with class imbalance emerging as the major factor influencing FPR and FNR, especially for sites with more PD cases. This research underscores the urgency of a rigorous analysis of a model’s behaviour in distributed setups to detect misdiagnosis risks and encourage developers to evaluate and optimize models beyond overall accuracy. Thus, comprehensive analyses of this type can help pave the way for the development of more equitable AI-based medical imaging models. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Contrastive Learning

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Reverse application of the Andrews protocol for assessing risks in a hypothetical nuclear accident

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nuclear engineering and Design 2025年 441卷

作者： Angelica C. Nogueira Hugo F. Menossi Rafael M. Hespanhol Andre C. Tavares Rodrigo C. Curzio Tercio Brum Edson R. Andrade Nuclear Engineering Graduate Program Military Institute of Engineering (IME) Rio de Janeiro Brazil Universidade do Oeste Paulista (UNOESTE) São Paulo Brazil Engineering Department Charleston Southern University North Charleston SC USA Herschend School of Education Gordon College Wenham MA USA Defense Engineering Graduate Program Military Institute of Engineering (IME) Rio de Janeiro Brazil University of Brasilia (UnB) Faculty of Science and Technology in Engineering Gama Distrito Federal Brazil Institute of Advanced Studies (IEAv) Brazilian Air Force São Paulo Brazil

This study introduces a novel approach to assessing radiobiological damage by employing an inverted version of the classical Andrews protocol (or Andrews nomogram) within the context of nuclear accidents. The methodology consists of two stages of computational simulation: The first stage simulates the release of radioactive materials from a pressurized water reactor (PWR), concentrating on scenarios of operational instability. In contrast, the second stage utilizes HotSpot Health Physics software to model the environmental dispersion of these materials. By estimating Total Effective Dose Equivalents (TEDE) at various locations and under different atmospheric stability conditions, we reverse the traditional sequence of the Andrews nomogram, which typically estimates lymphocyte counts based on radiation dose exposure. This innovative framework facilitates the development of a TEDE versus a Count curve, thereby enhancing the ability to anticipate the health implications following radiological incidents. The results highlight the importance of accurate modeling in predicting biological effects on populations exposed to radioactive releases and provide a tool to support responses and help design coping strategies enhancing the situational awareness of healthcare teams in nuclear emergencies.

关键词： Andrews curves Computational simulation nuclear accident Response support

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Electron spin dynamics guide cell motility

arXiv

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arXiv 2025年

作者： Wang, Kai Gilmer, Gabrielle Araña, Matheus Cândia Iijima, Hirotaka Bergmann, Juliana Woollard, Antonio Mesits, Boris McGraw, Meghan Zoltowski, Brian Cappellaro, Paola Ungar, Alex Pekker, David Waldeck, David H. Saxena, Sunil Lloyd, Seth Ambrosio, Fabrisia Discovery Center for Musculoskeletal Recovery Schoen Adams Research Institute at Spaulding BostonMA United States Department of Physical Medicine & Rehabilitation Spaulding Rehabilitation Hospital BostonMA United States Department of Physical Medicine & Rehabilitation Harvard Medical School BostonMA United States Cellular and Molecular Pathology Graduate Program University of Pittsburgh PittsburghPA United States Medical Scientist Training Program School of Medicine University of Pittsburgh PittsburghPA United States École Polytechnique Institut Polytechnique de Paris Palaiseau France Department of Physics & Astronomy University of Pittsburgh PittsburghPA United States Department of Chemistry Southern Methodist University DallasTX United States Department of Nuclear Science and Engineering Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Department of Chemistry University of Pittsburgh PittsburghPA United States Department of Mechanical Engineering Massachusetts Institute of Technology BostonMA United States

Diverse organisms exploit the geomagnetic field (GMF) for migration. Migrating birds employ an intrinsically quantum mechanical mechanism for detecting the geomagnetic field: absorption of a blue photon generates a radical pair whose two electrons precess at different rates in the magnetic field, thereby sensitizing cells to the direction of the GMF. In this work, using an in vitro injury model, we discovered a quantum-based mechanism of cellular migration. Specifically, we show that migrating cells detect the GMF via an optically activated, electron spin-based mechanism. Cell injury provokes acute emission of blue photons, and these photons sensitize muscle progenitor cells to the magnetic field. We show that the magnetosensitivity of muscle progenitor cells is (a) activated by blue light, but not by green or red light, and (b) disrupted by the application of an oscillatory field at the frequency corresponding to the energy of the electron-spin/magnetic field interaction. A comprehensive analysis of protein expression reveals that the ability of blue photons to promote cell motility is mediated by activation of calmodulin calcium sensors. Collectively, these data suggest that cells possess a light-dependent magnetic compass driven by electron spin dynamics. © 2025, CC BY.

关键词： Spin dynamics

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Deep learning inter-atomic potential for thermal and phonon behaviour of silicon carbide with quantum accuracy

arXiv

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arXiv 2021年

作者： Fu, Baoqin Sun, Yandong Zhang, Linfeng Wang, Han Xu, Ben Key Laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu610064 China Graduate School China Academy of Engineering Physics Beijing100193 China Program in Applied and Computational Mathematics Princeton University PrincetonNJ United States Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing100088 China

Silicon carbide (SiC) is an essential material for next generation semiconductors and components for nuclear plants. It’s applications are strongly dependent on its thermal conductivity, which is highly sensitive to microstructures. Molecular dynamics (MD) simulation is the most used methods to address thermal transportation mechanisms in devices or microstructures of nano-meters. However, the implementation of MD is limited in SiC because of lacking accurate inter-atomic potentials. In this work, using the Deep Potential (DP) methodology, we developed two inter-atomic potentials (DP-*Corresponding author. IAPs) for SiC based on two adaptively generated datasets within the density functional approximations at the local density and the generalized gradient levels. These two DP-IAPs manifest their speed with quantum accuracy in lattice dynamics simulations as well as scattering rate analysis of phonon transportation. Combining with molecular dynamics simulations, the thermal transport and mechanical properties were systematically investigated. The presented methodology and the inter-atomic potentials pave the way for a systematic approach to model heat transport in SiC related devices using multiscale modelling. Copyright © 2021, The Authors. All rights reserved.

关键词： Silicon carbide

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First Science Results from CTA LST-1 Telescope and status of LST-2-4 38

First Science Results from CTA LST-1 Telescope and status of...

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38th International Cosmic Ray Conference, ICRC 2023

作者： Mazin, D. Abe, K. Abe, S. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Artero, M. Asano, K. Aubert, P. Baktash, A. Bamba, A. Baquero Larriva, A. Baroncelli, L. Barres de Almeida, U. Barrio, J.A. Batkovic, I. Baxter, J. Becerra González, J. Bernardini, E. Bernardos, M.I. Bernete Medrano, J. Berti, A. Bhattacharjee, P. Biederbeck, N. Bigongiari, C. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Carrasco, M.S. Cassol, F. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chytka, L. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. De Lucia, M. de Menezes, R. Del Peral, L. Deleglise, G. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Pilato, A. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrara, G. Ferrarotto, F. Fiasson, A. Foffano, L. Freixas Coromina, L. Fröse, S. Fukami, S. Fukazawa, Y. Garcia, E. Garcia López, R. Gasbarra, C. Gasparrini, D. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, J. Green, D. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hashiyama, K. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Herrera Llorente, J. Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Hrabovsky, M. Hrupec, D. Hui, D. Hütten, M. Iarlori, M. Imazawa, R. Inada, T. Inome, Y. Ioka, K. Iori, M. Ishio, K. Jimenez Martinez, I. Jurysek, J. Kagaya, M. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kohri, K. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. Le Flour, T. Linhoff, M. Longo, F. López-Coto, R. López-Oramas, A. Loporchio, S. Lorini, A. Lozano Bahilo, J. Institute for Cosmic Ray Research University of Tokyo 5-1-5 Kashiwa-no-ha Kashiwa Chiba277-8582 Japan Max-Planck-Institut für Physik München80805 Germany Department of Physics Tokai University Japan Departament de Física Quàntica i Astrofísica Institut de Ciències delCosmos Universitat de Barcelona IEEC-UB Spain Instituto de Astrofísica de Andalucía-CSIC Spain EMFTEL department IPARCOS Universidad Complutense de Madrid Spain INAF - Osservatorio Astronomico di Roma Italy INFN Sezione di Napoli Italy INFN Sezione di Padova Università degli Studi di Padova Italy The Barcelona Institute of Science and Technology Spain LAPP Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS-IN2P3 Annecy France Universität Hamburg Institut für Experimentalphysik Germany Graduate School of Science University of Tokyo Japan Universidad del Azuay Ecuador INAF - Osservatorio di Astrofisica e Scienza dello spazio di Bologna Italy Centro Brasileiro de Pesquisas Físicas Brazil Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Spain CIEMAT Spain Department of Physics TU Dortmund University Germany INFN Sezione di Bari Politecnico di Bari Italy INAF - Osservatorio Astronomico di Brera Italy INFN Sezione di Trieste Università degli Studi di Udine Italy University of Geneva Département de physique nucléaire et corpusculaire Switzerland INFN Sezione di Catania Italy Italy Aix Marseille Univ CNRS IN2P3 CPPM France INFN Sezione di Bari Università di Bari Italy INFN Sezione di Torino Italy Palacky University Olomouc Faculty of Science Czech Republic University of Alcalá UAH Spain Port d’Informació Científica Spain University of Rijeka Department of Physics Croatia Institute for Theoretical Physics and Astrophysics Universität Würzburg Germany Institut für Theoretische Physik Lehrstuhl IV: Plasma-Astroteilchenphysik Ruhr-Universität Bochum Germany INFN Sezione di Roma La Sapienza Italy ILANCE CNRS France Physics Program Graduate School o

The prototype Large-Sized Telescope (LST-1) of the Cherenkov Telescope Array (CTA) was inaugurated on La Palma, Canary Islands, in 2018. Since then, the telescope is in the commissioning phase and takes regular gamma-ray data on astrophysical sources while waiting for other CTA telescopes in La Palma to be constructed. Here we present the status of the commissioning, lessons learned, the telescope performance, and scientific highlights achieved in the last couple of years. The science results include the detection of active galactic nuclei flares, studies of pulsar wind nebulae and pulsars, the detection of a Nova, and searches for gamma-ray emission from gamma-ray bursts. We also present the status of the construction of the three further LST telescopes (LST-2-4) in La Palma and plans for their commissioning. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Pulsars

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Detection of the 2021 Outburst of RS Ophiuchi with the LST-1 38

Detection of the 2021 Outburst of RS Ophiuchi with the LST-1

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38th International Cosmic Ray Conference, ICRC 2023

作者： Kobayashi, Yukiho Aguasca-Cabot, Arnau Bernardos Martín, María Isabel Green, David López-Coto, Rubén Abe, K. Abe, S. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Artero, M. Asano, K. Aubert, P. Baktash, A. Bamba, A. Baquero Larriva, A. Baroncelli, L. Barres de Almeida, U. Barrio, J.A. Batkovic, I. Baxter, J. Becerra González, J. Bernardini, E. Bernardos, M.I. Bernete Medrano, J. Berti, A. Bhattacharjee, P. Biederbeck, N. Bigongiari, C. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Carrasco, M.S. Cassol, F. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chytka, L. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. De Lucia, M. de Menezes, R. Del Peral, L. Deleglise, G. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Pilato, A. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrara, G. Ferrarotto, F. Fiasson, A. Foffano, L. Freixas Coromina, L. Fröse, S. Fukami, S. Fukazawa, Y. Garcia, E. Garcia López, R. Gasbarra, C. Gasparrini, D. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, J. Green, D. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hashiyama, K. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Herrera Llorente, J. Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Hrabovsky, M. Hrupec, D. Hui, D. Hütten, M. Iarlori, M. Imazawa, R. Inada, T. Inome, Y. Ioka, K. Iori, M. Ishio, K. Jimenez Martinez, I. Jurysek, J. Kagaya, M. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kohri, K. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. Le Flour, T. Linhoff, M. Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwa-no-ha Chiba Kashiwa277-8582 Japan Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Martí i Franquès 1 Barcelona08028 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain Max-Planck-Institut für Physik Föhringer Ring 6 München80805 Germany Department of Physics Tokai University Japan EMFTEL department IPARCOS Universidad Complutense de Madrid Spain INAF - Osservatorio Astronomico di Roma Italy INFN Sezione di Napoli Italy INFN Sezione di Padova Università degli Studi di Padova Italy The Barcelona Institute of Science and Technology Spain LAPP Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS-IN2P3 Annecy France Universität Hamburg Institut für Experimentalphysik Germany Graduate School of Science University of Tokyo Japan Universidad del Azuay Ecuador INAF - Osservatorio di Astrofisica e Scienza dello spazio di Bologna Italy Centro Brasileiro de Pesquisas Físicas Brazil Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Spain CIEMAT Spain Department of Physics TU Dortmund University Germany INFN Sezione di Bari Politecnico di Bari Italy INAF - Osservatorio Astronomico di Brera Italy INFN Sezione di Trieste Università degli Studi di Udine Italy University of Geneva Département de physique nucléaire et corpusculaire Switzerland INFN Sezione di Catania Italy Italy Aix Marseille Univ CNRS IN2P3 CPPM France INFN Sezione di Bari Università di Bari Italy INFN Sezione di Torino Italy Palacky University Olomouc Faculty of Science Czech Republic University of Alcalá UAH Spain Port d’Informació Científica Spain University of Rijeka Department of Physics Croatia Institute for Theoretical Physics and Astrophysics Universität Würzburg Germany Institut für Theoretische Physik Lehrstuhl IV: Plasma-Astroteilchenphysik Ruhr-Universität Boch

Novae are luminous explosions in close binaries which host a white dwarf and a companion donor star. They are triggered by a thermonuclear runaway when the white dwarf accretes a critical amount of matter from the secondary. Though novae are established as high-energy gamma-ray emitters through observations by the Fermi Large Area Telescope (LAT), the origin of the gamma-ray emission, whether it is hadronic or leptonic, had been under intense debate until very recently. RS Ophiuchi (RS Oph) is a well-known recurrent symbiotic nova with a recurrence time scale of 15 years. The most recent outburst of RS Oph in 2021 brought the first detection of very-high-energy (VHE) gamma rays from a nova ever. The first Large-Sized Telescope prototype (LST-1) of the Cherenkov Telescope Array observed this historic event along with H.E.S.S. and MAGIC. The LST-1 observations in the first days after the burst onset show a clear VHE gamma-ray signal from RS Oph. The low energy threshold of LST-1 allows us to reconstruct the RS Oph gamma-ray spectrum down to ∼30 GeV, providing the best connection of the VHE gamma-ray data to the Fermi LAT energy range. The results from the analysis of the LST-1 observations are consistent with those obtained with H.E.S.S. and MAGIC, and also support a hadronic origin for the observed gamma-ray fluxes. In this contribution, we will present the analysis results of the LST-1 observations of the 2021 outburst of RS Oph. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： White dwarfs

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First results of pulsar observations with the LST-1 38

First results of pulsar observations with the LST-1

引用

38th International Cosmic Ray Conference, ICRC 2023

作者： Mas-Aguilar, Álvaro Brunelli, Giulia Ceribella, Giovanni López-Moya, Marcos López-Coto, Rubén Abe, K. Abe, S. Aguasca-Cabot, A. Agudo, I. Alvarez Crespo, N. Antonelli, L.A. Aramo, C. Arbet-Engels, A. Arcaro, C. Artero, M. Asano, K. Aubert, P. Baktash, A. Bamba, A. Baquero Larriva, A. Baroncelli, L. Barres de Almeida, U. Barrio, J.A. Batkovic, I. Baxter, J. Becerra González, J. Bernardini, E. Bernardos, M.I. Bernete Medrano, J. Berti, A. Bhattacharjee, P. Biederbeck, N. Bigongiari, C. Bissaldi, E. Blanch, O. Bonnoli, G. Bordas, P. Brunelli, G. Bulgarelli, A. Burelli, I. Burmistrov, L. Buscemi, M. Cardillo, M. Caroff, S. Carosi, A. Carrasco, M.S. Cassol, F. Cauz, D. Cerasole, D. Ceribella, G. Chai, Y. Cheng, K. Chiavassa, A. Chikawa, M. Chytka, L. Cifuentes, A. Contreras, J.L. Cortina, J. Costantini, H. Dalchenko, M. Dazzi, F. De Angelis, A. de Bony de Lavergne, M. De Lotto, B. De Lucia, M. de Menezes, R. Del Peral, L. Deleglise, G. Delgado, C. Delgado Mengual, J. della Volpe, D. Dellaiera, M. Di Piano, A. Di Pierro, F. Di Pilato, A. Di Tria, R. Di Venere, L. Díaz, C. Dominik, R.M. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Eisenberger, L. Elsässer, D. Emery, G. Escudero, J. Fallah Ramazani, V. Ferrara, G. Ferrarotto, F. Fiasson, A. Foffano, L. Freixas Coromina, L. Fröse, S. Fukami, S. Fukazawa, Y. Garcia, E. Garcia López, R. Gasbarra, C. Gasparrini, D. Geyer, D. Giesbrecht Paiva, J. Giglietto, N. Giordano, F. Gliwny, P. Godinovic, N. Grau, R. Green, J. Green, D. Gunji, S. Günther, P. Hackfeld, J. Hadasch, D. Hahn, A. Hashiyama, K. Hassan, T. Hayashi, K. Heckmann, L. Heller, M. Herrera Llorente, J. Hirotani, K. Hoffmann, D. Horns, D. Houles, J. Hrabovsky, M. Hrupec, D. Hui, D. Hütten, M. Iarlori, M. Imazawa, R. Inada, T. Inome, Y. Ioka, K. Iori, M. Ishio, K. Jimenez Martinez, I. Jurysek, J. Kagaya, M. Karas, V. Katagiri, H. Kataoka, J. Kerszberg, D. Kobayashi, Y. Kohri, K. Kong, A. Kubo, H. Kushida, J. Lainez, M. Lamanna, G. Lamastra, A. IPARCOS Department of EMFTEL Universidad Complutense de Madrid MadridE-28040 Spain INAF-OAS Università di Bologna Bologna40129 Italy Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain Max-Planck-Institut for Physics Munich80805 Germany Department of Physics Tokai University Japan Institute for Cosmic Ray Research University of Tokyo Japan Departament de Física Quàntica i Astrofísica Institut de Ciències del Cosmos Universitat de Barcelona IEEC-UB Spain INAF Osservatorio Astronomico di Roma Italy INFN Sezione di Napoli Italy Max-Planck-Institut für Physik Germany INFN Sezione di Padova Università degli Studi di Padova Italy The Barcelona Institute of Science and Technology Spain LAPP Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS-IN2P3 Annecy France Universität Hamburg Institut für Experimentalphysik Germany Graduate School of Science University of Tokyo Japan Universidad del Azuay Ecuador INAF Osservatorio di Astrofisica e Scienza dello spazio di Bologna Italy Centro Brasileiro de Pesquisas Físicas Brazil Instituto de Astrofísica de Canarias Departamento de Astrofísica Universidad de La Laguna Spain CIEMAT Spain Department of Physics TU Dortmund University Germany INFN Sezione di Bari Politecnico di Bari Italy INAF Osservatorio Astronomico di Brera Italy INFN Sezione di Trieste Università degli Studi di Udine Italy University of Geneva Département de physique nucléaire et corpusculaire Switzerland INFN Sezione di Catania Italy Italy Aix Marseille Univ CNRS IN2P3 CPPM France INFN Sezione di Bari Università di Bari Italy INFN Sezione di Torino Italy Palacky University Olomouc Faculty of Science Czech Republic University of Alcalá UAH Spain Port d’Informació Científica Spain University of Rijeka Department of Physics Croatia Institute for Theoretical Physics and Astrophysics Universität Würzburg Germany Institut für Theoretische Physik Lehrstuhl IV: Plasma-Astroteilchenphysik Ruhr-Universität B

After the discovery of Crab, Vela, and Geminga pulsars at Very High Energies, the search for new pulsars at tens of GeV has been gaining huge importance. However, their steep spectra along with the sensitivity of the current generation of Imaging Atmospheric Cherenkov telescopes (IACTs) are limiting the capability to detect more pulsars. The LST-1 is the first prototype of the Large-Sized Telescope of the forthcoming CTA observatory with enhanced sensitivity at tens of GeV. The LST-1 started its commissioning phase in 2018, and since then it has observed the Crab pulsar regularly. Here, we show the first results of the analysis of the Crab and other pulsars taken with the LST-1. The two characteristic emission peaks of the Crab pulsar, P1, and P2, are detected with high significance showing a clear improvement in sensitivity over the previous generation of IACTs. The spectrum is reconstructed up to 450 GeV for P1 and up to 700 GeV for P2. The low energy threshold of LST-1 also allows us to measure the spectrum of the Crab pulsar in the overlapping region with the Fermi-LAT and cross-calibrate both instruments. The results obtained with the first pulsar observations with the LST-1 confirm the excellent potential of LST telescopes to study and discover new pulsars in the near future. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Shellfish

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