检索结果-内蒙古大学图书馆

arXiv 2020年

作者： Fu, Wanyi Sharma, Shobhit Abadi, Ehsan Iliopoulos, Alexandros-Stavros Wang, Qi Lo, Joseph Y. Sun, Xiaobai Segars, William P. Samei, Ehsan Department of Electrical and Computer Engineering Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Department of Physics Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Department of Computer Science Duke University DurhamNC27708 United States Department of Radiology Fourth Clinical Hospital of Hebei Medical University Heibei050011 China Departments of Electrical and Computer Engineering Biomedical Engineering Medical Physics Graduate Program Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Departments of Biomedical Engineering Medical Physics Graduate Program and Radiology Carl E. Ravin Advanced Imaging Laboratories Duke University DurhamNC27705 United States Carl E. Ravin Advanced Imaging Laboratories Medical Physics Graduate Program Departments of Radiology Electrical and Computer Engineering Biomedical Engineering and Physics Duke University DurhamNC27705 United States

Objective: This study aims to develop and validate a novel framework, iPhantom, for automated creation of patient-specific phantoms or "digital-twins (DT)" using patient medical images. The framework is applied to assess radiation dose to radiosensitive organs in CT imaging of individual patients. Method: From patient CT images, iPhantom segments selected anchor organs (e.g. liver, bones, pancreas) using a learning-based model developed for multi-organ CT segmentation. Organs challenging to segment (e.g. intestines) are incorporated from a matched phantom template, using a diffeomorphic registration model developed for multi-organ phantom-voxels. The resulting full-patient phantoms are used to assess organ doses during routine CT exams. Result: iPhantom was validated on both the XCAT (n=50) and an independent clinical (n=10) dataset with similar accuracy. iPhantom precisely predicted all organ locations with good accuracy of Dice Similarity Coefficients (DSC) >0.6 for anchor organs and DSC of 0.3-0.9 for all other organs. iPhantom showed Copyright © 2020, The Authors. All rights reserved.

关键词： Phantoms

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Author Correction: Engineered droplet-forming peptide as photocontrollable phase modulator for fused in sarcoma protein

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Nature communications 2024年第1期15卷 7213页

作者： Hao-Yu Chuang Ruei-Yu He Yung-An Huang Wan-Ting Hsu Ya-Jen Cheng Zheng-Rong Guo Niaz Wali Ing-Shouh Hwang Jiun-Jie Shie Joseph Jen-Tse Huang Institute of Chemistry Academia Sinica Taipei 115 Taiwan. Chemical Biology and Molecular Biophysics Taiwan International Graduate Program Academia Sinica Taipei 115 Taiwan. Department of Chemistry National Tsing Hua University Hsinchu 300 Taiwan. Neuroscience Program of Academia Sinica Academia Sinica Taipei 115 Taiwan. Institute of Molecular Biology Academia Sinica Taipei 115 Taiwan. Institute of Physics Academia Sinica Taipei 115 Taiwan. Institute of Chemistry Academia Sinica Taipei 115 Taiwan. jthuang@gate.sinica.edu.tw. Neuroscience Program of Academia Sinica Academia Sinica Taipei 115 Taiwan. jthuang@gate.sinica.edu.tw. Sustainable Chemical Science and Technology Taiwan International Graduate Program Academia Sinica Taipei 115 Taiwan. jthuang@gate.sinica.edu.tw. Department of Applied Chemistry National Chiayi University Chiayi City 600 Taiwan. jthuang@gate.sinica.edu.tw.

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Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC

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Physical Review Letters 2023年第6期130卷 061002-061002页

作者： H. Abe S. Abe V. A. Acciari T. Aniello S. Ansoldi L. A. Antonelli A. Arbet Engels C. Arcaro M. Artero K. Asano D. Baack A. Babić A. Baquero U. Barres de Almeida J. A. Barrio I. Batković J. Baxter J. Becerra González W. Bednarek E. Bernardini M. Bernardos A. Berti J. Besenrieder W. Bhattacharyya C. Bigongiari A. Biland O. Blanch G. Bonnoli Ž. Bošnjak I. Burelli G. Busetto R. Carosi M. Carretero-Castrillo G. Ceribella Y. Chai A. Chilingarian S. Cikota E. Colombo J. L. Contreras J. Cortina S. Covino G. D’Amico V. D’Elia P. Da Vela F. Dazzi A. De Angelis B. De Lotto A. Del Popolo M. Delfino J. Delgado C. Delgado Mendez D. Depaoli F. Di Pierro L. Di Venere E. Do Souto Espiñeira D. Dominis Prester A. Donini D. Dorner M. Doro D. Elsaesser G. Emery V. Fallah Ramazani L. Fariña A. Fattorini L. Font C. Fruck S. Fukami Y. Fukazawa R. J. García López M. Garczarczyk S. Gasparyan M. Gaug J. G. Giesbrecht Paiva N. Giglietto F. Giordano P. Gliwny N. Godinović J. G. Green D. Green D. Hadasch A. Hahn T. Hassan L. Heckmann J. Herrera D. Hrupec M. Hütten R. Imazawa T. Inada R. Iotov K. Ishio I. Jiménez Martínez J. Jormanainen D. Kerszberg Y. Kobayashi H. Kubo J. Kushida A. Lamastra D. Lelas F. Leone E. Lindfors L. Linhoff S. Lombardi F. Longo R. López-Coto M. López-Moya A. López-Oramas S. Loporchio A. Lorini E. Lyard B. Machado de Oliveira Fraga P. Majumdar M. Makariev G. Maneva N. Mang M. Manganaro S. Mangano K. Mannheim M. Mariotti M. Martínez A. Mas Aguilar D. Mazin S. Menchiari S. Mender S. Mićanović D. Miceli T. Miener J. M. Miranda R. Mirzoyan E. Molina H. A. Mondal A. Moralejo D. Morcuende V. Moreno T. Nakamori C. Nanci L. Nava V. Neustroev M. Nievas Rosillo C. Nigro K. Nilsson K. Nishijima T. Njoh Ekoume K. Noda S. Nozaki Y. Ohtani T. Oka J. Otero-Santos S. Paiano M. Palatiello D. Paneque R. Paoletti J. M. Paredes L. Pavletić M. Persic M. Pihet F. Podobnik P. G. Prada Moroni E. Prandini G. Principe C. Priyadarshi I. Puljak W. Rhode M. Ribó J. Rico C. Righi A. Rugliancich N. Sahakyan T. Saito S. Sakurai K. Satalecka F. G. Sat Japanese MAGIC Group: Institute for Cosmic Ray Research (ICRR) The University of Tokyo Kashiwa 277-8582 Chiba Japan Instituto de Astrofísica de Canarias and Departamento de Astrofísica Universidad de La Laguna E-38200 La Laguna Tenerife Spain National Institute for Astrophysics (INAF) I-00136 Rome Italy Università di Udine and INFN Trieste I-33100 Udine Italy Max-Planck-Institut für Physik D-80805 München Germany Università di Padova and INFN I-35131 Padova Italy Institut de Física d’Altes Energies (IFAE) The Barcelona Institute of Science and Technology (BIST) E-08193 Bellaterra (Barcelona) Spain Technische Universität Dortmund D-44221 Dortmund Germany Croatian MAGIC Group: University of Zagreb Faculty of Electrical Engineering and Computing (FER) 10000 Zagreb Croatia IPARCOS Institute and EMFTEL Department Universidad Complutense de Madrid E-28040 Madrid Spain Centro Brasileiro de Pesquisas Físicas (CBPF) 22290-180 URCA Rio de Janeiro (RJ) Brazil University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics 90-236 Lodz Poland Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n 18008 Granada Spain Deutsches Elektronen-Synchrotron (DESY) D-15738 Zeuthen Germany ETH Zürich CH-8093 Zürich Switzerland Università di Pisa and INFN Pisa I-56126 Pisa Italy Universitat de Barcelona ICCUB IEEC-UB E-08028 Barcelona Spain Armenian MAGIC Group: A. Alikhanyan National Science Laboratory 0036 Yerevan Armenia Centro de Investigaciones Energéticas Medioambientales y Tecnológicas E-28040 Madrid Spain Department for Physics and Technology University of Bergen Norway INFN MAGIC Group: INFN Sezione di Catania and Dipartimento di Fisica e Astronomia University of Catania I-95123 Catania Italy INFN MAGIC Group: INFN Sezione di Torino and Università degli Studi di Torino I-10125 Torino Italy INFN MAGIC Group: INFN Sezione di Bari and Dipartimento Interateneo di Fisica dell’Università e del Politecnico di Bari I-70125 Bari Italy

Linelike features in TeV γ rays constitute a “smoking gun” for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite γ-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic telescope system reaching γ-ray energies up to 100 TeV. We improved the sensitivity to spectral lines at high energies using large-zenith-angle observations and a novel background modeling method within a maximum-likelihood analysis in the energy domain. No linelike spectral feature is found in our analysis. Therefore, we constrain the cross section for dark matter annihilation into two photons to ⟨σv⟩≲5×10−28 cm3 s−1 at 1 TeV and ⟨σv⟩≲1×10−25 cm3 s−1 at 100 TeV, achieving the best limits to date for a dark matter mass above 20 TeV and a cuspy dark matter profile at the Galactic Center. Finally, we use the derived limits for both cuspy and cored dark matter profiles to constrain supersymmetric wino models.

关键词： Dark matter Gamma ray astronomy Particle dark matter Milky Way Cosmic ray & astroparticle detectors Cosmic rays & astroparticles Electromagnetic radiation astronomy Telescopes

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Lower Bounds to the Q factor of Electrically Small Resonators through Quasistatic Modal Expansion

arXiv

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arXiv 2021年

作者： Pascale, Mariano Mann, Sander A. Tzarouchis, Dimitrios C. Miano, Giovanni Alù, Andrea Forestiere, Carlo ICFO-Institut de Ciencies Fotoniques The Barcelona Institute of Science and Technology Castelldefels Barcelona08860 Spain Department of Electrical Engineering and Information Technology Università degli Studi di Napoli Federico II via Claudio 21 Napoli80125 Italy Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center of the City University of New York New YorkNY10016 United States Department of Electrical and System Engineering University of Pennsylvania PhiladelphiaPA19104 United States

The problem of finding the optimal current distribution supported by small radiators yielding the minimum quality (Q) factor is a fundamental problem in electromagnetism. Q factor bounds constrain the maximum operational bandwidth of devices including antennas, metamaterials, and nanoresonators, and have been featured in seminal papers in the past decades. Here, we determine the lower bounds of Q factors of small-size plasmonic and high-permittivity dielectric resonators, which are characterized by quasi-electrostatic and quasi-magnetostatic natural modes, respectively. We expand the induced current density field in the resonator in terms of these modes, leading to closed-form analytical expressions for the electric and magnetic polarizability tensors, whose largest eigenvalue is directly linked to the minimum Q factor. Our results allow also to determine in closed form the corresponding optimal current density field. In particular, when the resonator exhibits two orthogonal reflection symmetries the minimum Q factor can be simply obtained from the Q factors of the single current modes with non-vanishing dipole moments aligned along the major axis of the resonator. Overall, our results open exciting opportunities in the context of nano-optics and metamaterials, facilitating the analysis and design of optimally shaped resonators for enhanced and tailored light-matter interactions. Copyright © 2021, The Authors. All rights reserved.

关键词： Eigenvalues and eigenfunctions

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Efficient Focusing with Large Numerical Aperture Using a Hybrid Metalens

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Physical Review Applied 2020年第4期13卷 044016-044016页

作者： Ming Kang Younes Ra'di Diego Farfan Andrea Alù Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Photonics Initiative Advanced Science Research Center City University of New York New York 10031 USA Physics Program Graduate Center City University of New York New York 10016 USA Department of Electrical Engineering City College of The City University of New York New York 10031 USA

Focusing light using electrically thin layers is of paramount importance in several applications, from integrated optics to microwave engineering and sensing. Recently, gradient metasurfaces, which are electrically thin arrays of densely located polarizable particles, have been employed to perform different wave-front transformations, including focusing. In comparison to a bulk lens, these designs provide ultrathin geometries, but they suffer from fundamental limitations on their overall efficiency and achievable numerical aperture. Metagratings offer a solution for efficient beam steering at large angles, but it is challenging to utilize them in the small-angle limit. Here, we introduce a hybrid metalens design, which provides dramatic enhancement in lensing performance compared with that of state-of-the-art metasurfaces, combining metagratings and conventional gradient approaches. Our experimental prototype enables microwave focusing with large efficiency (η=0.479) and near-unity numerical aperture (NA=0.98), yielding a sharp focal point at the diffraction limit in the far field (FWHM=0.332λ). We propose a hybrid metalens design with exceptional performance in terms of efficiency and numerical aperture, opening up opportunities for high-throughput optical lithography, high-density data recording, focal plane arrays, radar, and communication systems.

关键词： Classical optics Integrated optics Metamaterials Optical & microwave phenomena Devices Surfaces

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A genuine correlation in piezoelectric properties of two-dimensional materials: A high-throughput computational study

arXiv

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arXiv 2020年

作者： Arlı, Cihan Kocabaş, Tugbey Çakır, Deniz Sevik, Cem Department of Materials Science and Engineering Institute of Graduate Program Eskisehir Technical University Eskiehir TR26555 Turkey Department of Physics and Astrophysics University of North Dakota Grand ForksND58202 United States Department of Mechanical Engineering Faculty of Engineering Eskisehir Technical University Eskiehir TR26555 Turkey

The rational design of two-dimensional piezoelectric materials has recently garnered increasing interest because of harnessing these materials in technological applications, including sensor technology, actuating devices, energy harvesting, and medical applications. Several materials possessing high piezoelectric response have been reported so far, but a high-throughput first-principles approach to estimate the piezoelectric potential of layered materials has not been performed yet. In this respect, we systematically investigated the piezoelectric (e11, d11) and elastic (C11 and C12) properties of 108 thermodynamically stable two-dimensional (2D) semiconductor materials by employing first-principle methods. Our calculations found a notable difference between the relaxed ion coefficients calculated with GGA and LDA functionals, indicating a strong exchange-correlation functional dependence. Nevertheless, both functionals yield the same trends for the elastic constants and piezoelectric coefficients. Our high-throughput approach demonstrates that the materials containing Group-V elements produce notably high piezoelectric strain constants, d11 > 40 pmV−1, and 42 of considered materials have the e11 coefficient higher than MoS2 insomuch as BrSSb has one of the largest d11 with a value of 503.6 pmV−1. Besides, we established simple empirical models to estimate the d11 coefficients by utilizing the relative ionic motion in the unit cell and the polarizability of the individual elements in the compounds. The proposed models, tested for both exchange-correlation functionals, are successful in estimating the piezoelectric constants of the studied materials with sufficient accuracy. Copyright © 2020, The Authors. All rights reserved.

关键词： Piezoelectricity

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GW190521 as a black-hole merger coincident with the ZTF19abanrhr flare

arXiv

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arXiv 2021年

作者： Bustillo, Juan Calderón Leong, Samson H.W. Chandra, Koustav McKernan, Barry Ford, K.E.S. Instituto Galego de Física de Altas Enerxías Universidade de Santiago de Compostela Galicia Santiago de Compostela15782 Spain Department of Physics The Chinese University of Hong Kong N.T. Shatin Hong Kong Department of Physics Indian Institute of Technology Bombay Powai Maharashtra Mumbai400076 India Department of Science CUNY-BMCC 199 Chambers St. New YorkNY10007 United States Department of Astrophysics American Museum of Natural History Central Park West New YorkNY10028 United States Physics Program The Graduate Center CUNY New YorkNY10016 United States Center for Computational Astrophysics Flatiron Institute New YorkNY10010 United States

We present an analysis that reconciles the gravitational wave signal GW190521 observed by the Advanced LIGO and Advanced Virgo detectors with the electromagnetic flare ZTF19abanrhr observed by the Zwicky Transient Facility. We analyze GW190521 under a mass-ratio prior uniform in Q ∈ [1, 4] using the state-of-the-art waveform model for black-hole mergers NRSur7dq4. We find a 90% credible region for the black-hole masses extending far outside what originally reported by [1], where our maximum likelihood masses reside. We find a 15% probability that both black holes avoid the pair-instability supernova gap. We infer a three-dimensional sky-location highly consistent with ZTF19abanrhr, obtaining an odds-ratio OC/R = 72: 1 that strongly favors the hypothesis of a true coincidence over a random one. Combining this event with the neutron-star merger GW170817, we estimate a Hubble constant H0 = 72.1-6.4+10.6km s-1 Mpc-1 at the 68% credible level. Copyright © 2021, The Authors. All rights reserved.

关键词： Merging

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The HASHTAG project II. Giant molecular cloud properties across the M31 disc

arXiv

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arXiv 2025年

作者： Deng, Yikai Li, Zongnan Li, Zhiyuan Liu, Lijie Ren, Zhiyuan Athikkat-Eknath, Gayathri de Grijs, Richard Eales, Stephen A. Eden, David J. Iono, Daisuke Jiao, Sihan Lee, Bumhyun Li, Di Saintonge, Amelie Smith, Matthew W.L. Tang, Xindi Tsai, Chaowei van der Giessen, Stefan A. Williams, Thomas G. Wu, Jingwen National Astronomical Observatories Chinese Academy of Sciences A20 Datun Road Chaoyang District Beijing100101 China University of Chinese Academy of Sciences Beijing100049 China School of Astronomy and Space Science Nanjing University Nanjing210023 China National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Nanjing210023 China Technical University of Denmark Kgs LyngbyDK2800 Denmark DTU-Space Technical University of Denmark Elektrovej 327 Kgs. LyngbyDK2800 Denmark School of Physics & Astronomy Cardiff University The Parade CardiffCF24 3AA United Kingdom School of Mathematical and Physical Sciences Macquarie University Balaclava Road SydneyNSW2109 Australia Astrophysics and Space Technologies Research Centre Macquarie University Balaclava Road SydneyNSW2109 Australia International Space Science Institute–Beijing 1 Nanertiao Zhongguancun Hai Dian District Beijing100190 China Department of Physics University of Bath Claverton Down BathBA2 7AY United Kingdom Armagh Observatory and Planetarium College Hill ArmaghBT61 9DB United Kingdom Astronomical Science Program The Graduate University for Advanced Studies SOKENDAI 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Department of Astronomy Yonsei University 50 Yonsei-ro Seodaemun-gu Seoul03722 Korea Republic of Department of Astronomy Tsinghua Centre for Astrophysics Tsinghua University Beijing100084 China Department of Physics & Astronomy University College London Gower Place LondonWC1E 6BT United Kingdom Auf dem Hu¥gel 69 BonnD-53121 Germany Xinjiang Astronomical Observatory Chinese Academy of Sciences Urumqi830011 China Sterrenkundig Observatorium Ghent University Krijgslaan 281 - S9 Gent9000 Belgium Dept. Fisica Teorica y del Cosmos GranadaE-18071 Spain Sub-department of Astrophysics Department of Physics University of Oxford Keble Road OxfordOX1 3RH United Kingdom

We present a study of giant molecular cloud (GMC) properties in the Andromeda galaxy (M31) using CO(3-2) data from the James Clerk Maxwell Telescope (JCMT) in selected regions across the disc and in the nuclear ring, and comparing them with CO(1-0) observations from the IRAM 30m telescope in the same regions. We find that GMCs in the centre of M31 generally exhibit larger velocity dispersions (σ) and sizes (R) compared to those in the disc, while their average surface density (Σ) and turbulent pressure (Pturb) are lower. This low turbulent pressure in the central region is primarily due to the low density of molecular gas. The estimated GMC properties depend on the choice of CO transitions. Compared to CO(1-0), CO(3-2) exhibits smaller velocity dispersion and equivalent radius but higher surface density. These differences highlight the distinct physical conditions probed by different molecular gas tracers. We estimate the virial parameter αvir ∝ σ2R/Σ and find that most molecular clouds exhibit high values (αvir ∼ 4 − 6) for both CO transitions, indicating that they are unbound. Furthermore, clouds in the nuclear ring display even larger αvir values of 100, suggesting that they may be highly dynamic, short-lived structures, although they could potentially achieve equilibrium under the external pressure exerted by the surrounding interstellar medium. Copyright © 2025, The Authors. All rights reserved.

关键词： Atmospheric density

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Effects of galaxy environment on merger fraction

arXiv

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arXiv 2024年

作者： Pearson, W.J. Santos, D.J.D. Goto, T. Huang, T.-C. Kim, S.J. Matsuhara, H. Pollo, A. Ho, S.C.-C. Hwang, H.S. Malek, K. Nakagawa, T. Romano, M. Serjeant, S. Suelves, L. Shim, H. White, G.J. National Centre for Nuclear Research Pasteura 7 Warszawa02-093 Poland Max Planck Institute for Extraterrestrial Physics Giesenbachstrase 1 GarchingD-85748 Germany Institute of Astronomy National Tsing Hua University 101 Section 2. Kuang-Fu Road Hsinchu30013 Taiwan Department of Space and Astronautical Science Graduate University for Advanced Studies SOKENDAI Shonankokusaimura Hayama Miura District Kanagawa240-0193 Japan Institute of Space and Astronautical Science Japan Aerospace Exploration Agency 3-1-1 Yoshinodai Chuo-ku Sagamihara Kanagawa252-5210 Japan Research School of Astronomy and Astrophysics The Australian National University CanberraACT2611 Australia Centre for Astrophysics and Supercomputing Swinburne University of Technology P.O. Box 218 HawthornVIC3122 Australia OzGrav: The Australian Research Council Centre of Excellence for GravitationalWave Discovery HawthornVIC3122 Australia ASTRO3D: The Australian Research Council Centre of Excellence for All-sky Astrophysics in 3D ACT2611 Australia Astronomy Program Department of Physics and Astronomy Seoul National University 1 Gwanak-ro Gwanak-gu Seoul08826 Korea Republic of SNU Astronomy Research Center Seoul National University 1 Gwanak-ro Gwanak-gu Seoul08826 Korea Republic of INAF-Osservatorio Astronomico di Padova Vicolo dell'Osservatorio 5 PadovaI-35122 Italy School of Physical Sciences The Open University Walton Hall Milton KeynesMK7 6AA United Kingdom Department of Earth Science Education Kyungpook National University 80 Daehak-ro Buk-gu Daegu41566 Korea Republic of Space Science and Technology Division RALSpace STFC Rutherford Appleton Laboratory Chilton DidcotOX11 0QX United Kingdom

Aims. In this work, we intend to examine how environment influences the merger fraction, from the low density field environment to higher density groups and clusters. We also aim to study how the properties of a group or cluster, as well as the position of a galaxy in the group or cluster, influences the merger fraction. *** identified galaxy groups and clusters in the North Ecliptic Pole using a friends-of-friends algorithm and the local density. Once identified, we determined the central galaxies, group radii, velocity dispersions, and group masses of these groups and clusters. Merging systems were identified with a neural network as well as *** these, we examined how the merger fraction changes as the local density changes for all galaxies as well as how the merger fraction changes as the properties of the groups or clusters change. Results. We find that the merger fraction increases as local density increases and decreases as the velocity dispersion increases, as is often found in literature. A decrease in merger fraction as the group mass increases is also found. We also find groups with larger radii have higher merger fractions. The number of galaxies in a group does not influence the merger fraction. Conclusions. The decrease in merger fraction as group mass increases is a result of the link between group mass and velocity dispersion. Hence, this decrease of merger fraction with increasing mass is a result of the decrease of merger fraction with velocity dispersion. The increasing relation between group radii and merger fraction may be a result of larger groups having smaller velocity dispersion at a larger distance from the centre or larger groups hosting smaller, infalling groups with more mergers. However, we do not find evidence of smaller groups having higher merger fractions. Copyright © 2024, The Authors. All rights reserved.

关键词： Galaxies

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Cross-calibration and combined analysis of the CTA-LST prototype and the MAGIC telescopes

arXiv

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arXiv 2021年

作者： Ohtani, Y. Berti, A. Depaoli, D. Di Pierro, F. Green, D. Heckmann, L. Hutten, M. Inada, T. Lopez-Coto, R. Medina, E. Moralejo, A. Morcuende, D. Pirola, G. Strzys, M. Suda, Y. Vovk, I. ICRR The University of Tokyo 1-5-1 Kashiwa-no-ha Kashiwa City Chiba Japan Max Planck Institute for Physics Fohringer Ring 6 Munchen80805 Germany INFN Sezione di Torino Via Pietro Giuria 1 Torino10125 Italy INFN Sezione di Padova Via Francesco Marzolo 8 Padova35131 Italy IFAE Edifici Cn Campus Universitat Autonoma de Barcelona Barcelona08193 Spain Universidad Complutense de Madrid Av. Seneca 2 Madrid28040 Spain Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan

The Cherenkov Telescope Array (CTA) will be the next generation gamma-ray observatory, which will consist of three kinds of telescopes of different sizes. Among those, the Large Size Telescope (LST) will be the most sensitive in the low energy range starting from 20 GeV. The prototype LST (LST-1) proposed for CTA was inaugurated in October 2018 in the northern hemisphere site, La Palma (Spain), and is currently in its commissioning phase. MAGIC is a system of two gamma-ray Cherenkov telescopes of the current generation, located approximately 100 m away from LST-1, that have been operating in stereoscopic mode since 2009. Since LST-1 and MAGIC can observe the same air shower events, we can compare the brightness of showers, estimated energies of gamma rays, and other parameters event by event, which can be used to cross-calibrate the telescopes. Ultimately, by performing combined analyses of the events triggering the three telescopes, we can reconstruct the shower geometry more accurately, leading to better energy and angular resolutions, and a better discrimination of the background showers initiated by cosmic rays. For that purpose, as part of the commissioning of LST-1, we performed joint observations of established gamma-ray sources with LST-1 and MAGIC. Also, we have developed Monte Carlo simulations for such joint observations and an analysis pipeline which finds event coincidence in the offline analysis based on their timestamps. In this work, we present the first detection of an astronomical source, the Crab Nebula, with combined observation of LST-1 and MAGIC. Moreover, we show results of the inter-telescope cross-calibration obtained using Crab Nebula data taken during joint observations with LST-1 and MAGIC. Copyright © 2021, The Authors. All rights reserved.

关键词： Telescopes

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