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Long-term study of the intermittent extreme behaviour of 1ES 2344+514 38

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Long-term study of the intermittent extreme behaviour of 1ES...

38th International Cosmic Ray Conference, ICRC 2023

作者： Arbet-Engels, A. Mondal, H.A. Fukami, S. D’Ammando, F. Dorner, D. Chatterjee, R. Majumdar, P. Manganaro, M. Hovatta, T. Das, S. Raiteri, C.M. Villata, M. Perri, M. Verrechia, F. Leto, C. Filippenko, A. Zheng, W. Abe, H. Abe, S. Abhir, J. Acciari, V.A. Agudo, I. Aniello, T. Ansoldi, S. Antonelli, L.A. Arbet Engels, A. Arcaro, C. Artero, M. Asano, K. Baack, D. Babić, A. Baquero, A. Barres de Almeida, U. Barrio, J.A. Batković, I. Baxter, J. Becerra González, J. Bednarek, W. Bernardini, E. Bernardos, M. Bernete, J. Berti, A. Besenrieder, J. Bigongiari, C. Biland, A. Blanch, O. Bonnoli, G. Bošnjak, Ž. Burelli, I. Busetto, G. Campoy-Ordaz, A. Carosi, A. Carosi, R. Carretero-Castrillo, M. Castro-Tirado, A.J. Ceribella, G. Chai, Y. Chatterjee, R. Chilingarian, A. Cifuentes, A. Cikota, S. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D’Ammando, F. D’Amico, G. D’Elia, V. Da Vela, P. Dazzi, F. De Angelis, A. De Lotto, B. Del Popolo, A. Delfino, M. Delgado, J. Delgado Mendez, C. Depaoli, D. Di Pierro, F. Di Venere, L. Dominis Prester, D. Donini, A. Doro, M. Elsaesser, D. Emery, G. Escudero, J. Fariña, L. Fattorini, A. Foffano, L. Font, L. Fröse, S. Fukazawa, Y. García López, R.J. Garczarczyk, M. Gasparyan, S. Gaug, M. Giesbrecht Paiva, J.G. Giglietto, N. Giordano, F. Gliwny, P. Godinović, N. Grau, R. Green, D. Green, J.G. Hadasch, D. Hahn, A. Hassan, T. Heckmann, L. Herrera, J. Hrupec, D. Hütten, M. Imazawa, R. Inada, T. Iotov, R. Ishio, K. Jiménez Martínez, I. Jormanainen, J. Kerszberg, D. Kluge, G.W. Kobayashi, Y. Kouch, P.M. Kubo, H. Kushida, J. Láinez Lezáun, M. Lamastra, A. Lelas, D. Leone, F. Lindfors, E. Linhoff, L. Lombardi, S. Longo, F. López-Coto, R. López-Moya, M. López-Oramas, A. Loporchio, S. Lorini, A. Lyard, E. Machado de Oliveira Fraga, B. Majumdar, P. Makariev, M. Maneva, G. Mang, N. Manganaro, M. Mangano, S. Mannheim, K. Mariotti, M. Martínez, M. Martínez-Chicharro, M. Mas-Aguilar, A. Mazin, D. Menchiari, S. Saha Inst. of Nuclear Physics A CI of Homi Bhabha National Inst. West Bengal Kolkata700064 India INAF - Istituto di Radioastronomia Via Gobetti 101 BolognaI-40129 Italy School of Astrophysics Presidency University 86/1 College Street Kolkata700073 India University of Rijeka Faculty of Physics Rijeka51000 Croatia - ASI via del Politecnico s.n.c. RomaI-00133 Italy INAF Osservatorio Astrofisico di Torino Pino TorineseI-10025 Italy University of Turku TurkuFI-20014 Finland Aalto University Metsähovi Radio Observatory Metsähovintie 114 Kylmälä02540 Finland Italian Space Agency ASI via del Politecnico snc Roma00133 Italy INAF - Osservatorio Astronomico di Roma via di Frascati 33 MonteporzioI-00040 Italy Department of Astronomy University of California BerkeleyCA94720-3411 United States Miller Institute for Basic Research in Science University of California BerkeleyCA94720 United States The University of Tokyo Chiba Kashiwa277-8582 Japan ETH Zürich ZürichCH-8093 Switzerland Instituto de Astrofísica de Canarias Dpto. de Astrofísica Universidad de La Laguna Tenerife La LagunaE-38200 Spain Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain RomeI-00136 Italy Università di Udine INFN Trieste UdineI-33100 Italy Max-Planck-Institut für Physik MünchenD-80805 Germany Università di Padova INFN PadovaI-35131 Italy Bellaterra BarcelonaE-08193 Spain Technische Universität Dortmund DortmundD-44221 Germany Zagreb10000 Croatia IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain URCA RJ Rio de Janeiro22290-180 Brazil University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain Departament de Física CERES-IEEC Universitat Autònoma de Barcelona BellaterraE-08193 Spain Università di Pisa INFN Pisa Pisa

Extreme high-frequency-peaked BL Lac objects (EHBLs) are the most energetic persistent sources in the Universe. They are characterized by a spectral energy distribution (SED) featuring a synchrotron peak energy above 1 keV. 1ES 2344+514 is a blazar known to behave as an EHBL intermittently. Until now, its EHBL nature was only reported during flares, but a coherent picture is missing as unbiased monitoring campaigns are lacking. This work presents the longest observing campaign from radio to very-high-energy (VHE) frequencies performed so far on 1ES2344+514. Using observations during 2019-2021, we carry out a systematic investigation of the intermittent EHBL phases. Together with MAGIC, the dataset also includes X-ray observations from NuSTAR, XMM-Newton, and AstroSAT, providing an unprecedented determination of the two SED components. For the first time we report a clear EHBL behaviour during a low flux activity in 1ES 2344+514. It implies a significant hardening of the electron distribution inside the jet independent of flux. We also detect a bright X-ray state characterized by an unusually soft spectra, thus violating the harder-when-brighter relation typically found in blazars. The SED study further reveals an excess in the ultraviolet data with respect to the extrapolation of the X-ray spectrum, suggesting at least two regions contributing to the synchrotron flux. Finally we investigate a gamma-ray flare not accompanied by an X-ray counterpart. This peculiar outburst is interpreted using a time-dependent model involving two emitting components. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Synchrotrons

Bridging between type IIb and Ib supernovae: SN IIb 2022crv with a very thin Hydrogen envelope

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arXiv 2023年

作者： Gangopadhyay, Anjasha Maeda, Keiichi Singh, Avinash Nayana, A.J. Nakaoka, Tatsuya Kawabata, Koji S. Taguchi, Kenta Singh, Mridweeka Chandra, Poonam Ryder, Stuart D. Dastidar, Raya Yamanaka, Masayuki Kawabata, Miho Alsaberi, Rami Z.E. Dukiya, Naveen Teja, Rishabh Singh Ailawadhi, Bhavya Dutta, Anirban Sahu, D.K. Moriya, Takashi J. Misra, Kuntal Tanaka, Masaomi Chevalier, Roger Tominaga, Nozomu Uno, Kohki Imazawa, Ryo Hamada, Taisei Hori, Tomoya Isogai, Keisuke Hiroshima Astrophysical Science Centre Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima739-8526 Japan Department of Astronomy Kyoto University Kitashirakawa-Oiwake-cho Sakyo-ku Kyoto606-8502 Japan Indian Institute of Astrophysics Koramangala 2nd Block Bangalore560034 India Department of Physics Graduate School of Advanced Science and Engineering Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima739-8526 Japan National Radio Astronomy Observatory 520 Edgemont Road CharlottesvilleVA22903 United States School of Mathematical and Physical Sciences Macquarie University NSW2109 Australia Astrophysics and Space Technologies Research Centre Macquarie University SydneyNSW2109 Australia Instituto de Astrofísica Universidad Andres Bello Fernandez Concha 700 Las Condes RM Santiago Chile Millennium Institute of Astrophysics Nuncio Monsenor Sótero Sanz 100 Providencia Santiago8320000 Chile Graduate School of Science and Engineering Kagoshima University 1-21-35 Korimoto Kagoshima Kagoshima890-0065 Japan Nishi-Harima Astronomical Observatory Center for Astronomy University of Hyogo 407-2 Nishigaichi Sayo-cho Hyogo Sayo679-5313 Japan Western Sydney University Locked Bag 1797 PenrithNSW2751 Australia Aryabhatta Research Institute of observational sciencES Manora Peak Nainital263 002 India Department of Applied Physics Mahatma Jyotiba Phule Rohilkhand University Bareilly243006 India Pondicherry University Chinna Kalapet Puducherry Kalapet605014 India Department of Physics Deen Dayal Upadhyaya Gorakhpur University Gorakhpur273009 India National Astronomical Observatory of Japan National Institutes of Natural Sciences 2-21-1 Osawa Mitaka Tokyo181-8588 Japan School of Physics and Astronomy Faculty of Science Monash University ClaytonVIC3800 Australia Astronomical Institute Tohoku University Aoba Sendai980-8578 Japan University Of Virginia Astronomy Building 530 McCormick Road CharlottesvilleVA2290

We present optical, near-infrared, and radio observations of supernova (SN) SN IIb 2022crv. We show that it retained a very thin H envelope and transitioned from a SN IIb to a SN Ib;prominent Hα seen in the pre-maximum phase diminishes toward the post-maximum phase, while He i lines show increasing strength. SYNAPPS modeling of the early spectra of SN 2022crv suggests that the absorption feature at 6200 Å is explained by a substantial contribution of Hα together with Si ii, as is also supported by the velocity evolution of Hα. The light-curve evolution is consistent with the canonical stripped-envelope supernova subclass but among the slowest. The light curve lacks the initial cooling phase and shows a bright main peak (peak MV =−17.82±0.17 mag), mostly driven by radioactive decay of 56Ni. The light-curve analysis suggests a thin outer H envelope (Menv ∼0.05 M☉) and a compact progenitor (Renv ∼3 R☉). An interaction-powered synchrotron self-absorption (SSA) model can reproduce the radio light curves with a mean shock velocity of 0.1c. The mass-loss rate is estimated to be in the range of (1.9−2.8) × 10−5 M☉ yr−1 for an assumed wind velocity of 1000 km s−1, which is on the high end in comparison with other compact SNe IIb/Ib. SN 2022crv fills a previously unoccupied parameter space of a very compact progenitor, representing a beautiful continuity between the compact and extended progenitor scenario of SNe IIb/Ib. Copyright © 2023, The Authors. All rights reserved.

关键词： Supernovae

The thickness dependence of quantum oscillations in ferromagnetic Weyl metal SrRuO3

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npj Quantum Materials 2023年第1期8卷 1-10页

作者： Uddipta Kar Akhilesh Kr. Singh Chih-Yu Lin Bipul Das Cheng-Tung Cheng Wei-Li Lee Yu-Te Hsu M. Berben S. Wiedmann Song Yang Chun-Yen Lin Chia-Hung Hsu Wei-Cheng Lee Institute of Physics Academia Sinica Nankang Taipei 11529 Taiwan Nano Science and Technology Taiwan International Graduate Program Academia Sinica and National Taiwan university Taipei Taiwan Department of Physics National Taiwan University Taipei 10617 Taiwan High Field Magnet Laboratory (HFML-EMFL) Radboud University Toernooiveld 7 6525 ED Nijmegen The Netherlands Radboud University Institute for Molecules and Materials Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands Scientific Research Division National Synchrotron Radiation Research Center Hsinchu 30076 Taiwan Department of Physics Applied Physics and Astronomy Binghamton University Binghamton NY 13902 USA

In a thin Weyl semimetal, a thickness dependent Weyl-orbit quantum oscillation was proposed to exist, originating from a nonlocal cyclotron orbit via electron tunnelings between top and bottom Fermi-arc surface states. Here, magneto-transport measurements were carried out on untwinned Weyl metal SrRuO3thin films. In particular, quantum oscillations with a frequencyFs1≈ 30 T were identified, corresponding to a small Fermi pocket with a light effective mass. Its oscillation amplitude appears to be at maximum for thicknesses in a range of 10 to 20 nm, and the phase of oscillation exhibits a systematic change with film thickness. The constructed Landau fan diagram shows an unusual concave downward curvature in the 1/μ0Hn-ncurve, wherenis the Landau level index. From thickness and field-orientation dependence, theFs1oscillation is attributed to be of surface origin. Those findings can be understood within the framework of the Weyl-orbit quantum oscillation effect with non-adiabatic corrections.

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Manganese-doped oleic acid functionalized whitlockite/polycaprolactone nanocomposite scaffolds enhance bone regeneration through improved dispersibility and antioxidative capacity

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Chemical Engineering Journal 2025年 518卷

作者： Liu, Xiaofan Liu, Yang Wang, Peiyu Tian, Ye Zhao, Yuping Wang, Yuxuan Zheng, Wenqian Wang, Yi Shi, Yaru Xie, Yi Zhou, Na González, Fermín E. Sun, Hongchen Zhou, Ding Xu, Xiaowei Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling Hospital of Stomatology Jilin University Changchun 130021 China Graduate Program in Applied Physics Northwestern University Evanston 60208 IL United States School of Pharmacy State Key Laboratory of Quality Research in Chinese Medicines and Laboratory of Drug Discovery from Natural Resources and Industrialization Macau University of Science and Technology Macau 999078 China Laboratory of Experimental Immunology & Cancer Faculty of Dentistry University of Chile Santiago 8380492 Chile

Bone defects present significant clinical challenges due to the complexities of healing. While polycaprolactone (PCL) scaffolds offer promising mechanical support for bone tissue engineering, their limited bioactivity and dispersibility issues with bioactive fillers restrict their effectiveness. Here, we develop manganese-doped oleic acid-functionalized whitlockite (Mn-OAWH) nanoparticles designed to enhance both the mechanical and biological properties of PCL scaffolds. The nanoparticles were synthesized via a hydrothermal approach using oleic acid as both solvent and surface ligand, enabling superior dispersibility in dichloromethane and uniform integration with PCL. Characterization of the resulting 3D printed Mn-OAWH/PCL composite scaffolds confirmed enhanced compressive strength, supported by both mechanical testing and finite element analysis. In vitro studies demonstrated that the release of Mn²⁺, Mg²⁺, and Ca²⁺ ions significantly promoted osteogenic proliferation, exhibited strong antioxidative properties, and accelerated osteogenic differentiation. Furthermore, in vivo implantation in a rat critical-sized cranial defect model revealed significantly improved bone formation compared to undoped and PCL-only controls. These findings establish Mn-OAWH/PCL composite scaffolds as a promising platform for bone tissue engineering, offering both enhanced mechanical support and biological functionality through improved nanoparticle dispersibility, strong antioxidative properties and osteogenic activity.

关键词： Bone regeneration Homogeneous nanocomposite scaffold Manganese doping Oleic acid-functionalized whitlockite nanoparticles Oxidative stress alleviation

Collective Motility, Mechanical Waves, and Durotaxis in Cell Clusters

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arXiv 2020年

作者： Deng, Youyuan Levine, Herbert Mao, Xiaoming Sander, Leonard M. Center for Theoretical Biological Physics Rice University HoustonTX77030-1402 United States Applied Physics Graduate Program Rice University HoustonTX77005-1827 United States Department of Physics Northeastern University BostonMA02115 United States Department of Physics University of Michigan Ann ArborMI48109-1040 United States Center for the Study of Complex Systems University of Michigan Ann ArborMI48109-1107 United States

When epithelial cell clusters move in a collective manner on a substrate mechanical signals play a major role in organizing the coherent behavior. There are a number of unexplained experimental results from traction force microscopy for a system of this type (MDCK cell clusters). These include: the internal strains are tensile even for clusters that expand by proliferation;the tractions on the substrate are confined to the edges of the cluster;in many cases there are density waves within the cluster;there is collective durotaxis of the cluster even though individual cells show no effect;and for cells in an annulus there is a transition between expanding clusters with proliferation and non-proliferating cases where cells rotate around the annulus. We formulate a simplified mechanical model which explains all of these effects in a straight-forward manner. The central feature of the model is to use a molecular clutch picture which allows "stalling" – inhibition of cell contraction and motility by external forces. Stalled cells are passive elements from a physical point of view and the un-stalled cells are active. When we attach cells to the substrate and to each other, and take into account contact inhibition of locomotion, we get a simple picture that gives all the mechanical results noted above. Copyright © 2020, The Authors. All rights reserved.

关键词： Cells

Tunneling spectroscopy of c-axis epitaxial cuprate junctions

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Physical Review B 2020年第22期101卷 224512-224512页

作者： Panpan Zhou Liyang Chen Ilya Sochnikov Tsz Chun Wu Matthew S. Foster Anthony T. Bollinger Xi He Ivan Božović Douglas Natelson Department of Physics and Astronomy Rice University Houston Texas 77005 USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston Texas 77005 USA Department of Physics University of Connecticut Storrs Connecticut 06269 USA Brookhaven National Laboratory Upton New York 11973–5000 USA Department of Chemistry Yale University New Haven Connecticut 06520 USA Department of Electrical and Computer Engineering Rice University Houston Texas 77005 USA Department of Materials Science and NanoEngineering Rice University Houston Texas 77005 USA

Atomically precise epitaxial structures are unique systems for tunneling spectroscopy that minimize extrinsic effects of disorder. We present a systematic tunneling spectroscopy study, over a broad doping, temperature, and bias range, in epitaxial c-axis La2−xSrxCuO4/La2CuO4/La2−xSrxCuO4 heterostructures. The behavior of these superconductor/insulator/superconductor (SIS) devices is unusual. Down to 20 mK there is complete suppression of c-axis Josephson critical current with a barrier of only 2 nm of La2CuO4, and the zero-bias conductance remains at 20–30% of the normal-state conductance, implying a substantial population of in-gap states. Tunneling spectra show greatly suppressed coherence peaks. As the temperature is raised, the superconducting gap fills in rather than closing at Tc. For all doping levels, the spectra show an inelastic tunneling feature at ∼80 meV, suppressed as T exceeds Tc. These nominally simple epitaxial cuprate junctions deviate markedly from expectations based on the standard Bardeen-Cooper-Schrieffer theory.

关键词： Coherence length Impurities in superconductors Josephson effect Quasiparticles & collective excitations Superconducting gap Superconducting phase transition d-wave Cuprates Heterostructures High-temperature superconductors Multilayer thin films Scanning tunneling spectroscopy

Very-high-energy gamma-ray emission from GRB 201216C detected by MAGIC 37

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Very-high-energy gamma-ray emission from GRB 201216C detecte...

37th International Cosmic Ray Conference, ICRC 2021

作者： Fukami, Satoshi Berti, Alessio Loporchio, Serena Suda, Yusuke Nava, Lara Noda, Koji Bošnjak, Željka Asano, Katsuaki Longo, Francesco Acciari, V.A. Ansoldi, S. Antonelli, L.A. Arbet Engels, A. Artero, M. Baack, D. Babić, A. Baquero, A. Barres de Almeida, U. Barrio, J.A. Batković, I. Becerra González, J. Bednarek, W. Bellizzi, L. Bernardini, E. Bernardos, M. Besenrieder, J. Bhattacharyya, W. Bigongiari, C. Biland, A. Blanch, O. Bökenkamp, H. Bonnoli, G. Busetto, G. Carosi, R. Ceribella, G. Cerruti, M. Chai, Y. Chilingarian, A. Cikota, S. Colak, S.M. Colombo, E. Contreras, J.L. Cortina, J. Covino, S. D'Amico, G. D'Elia, V. Da Vela, P. Dazzi, F. De Angelis, A. De Lotto, B. Delfino, M. Delgado, J. Delgado Mendez, C. Depaoli, D. Di Pierro, F. Di Venere, L. Do Souto Espiñeira, E. Dominis Prester, D. Donini, A. Dorner, D. Doro, M. Elsaesser, D. Fallah Ramazani, V. Fattorini, A. Fonseca, M.V. Font, L. Fruck, C. Fukazawa, Y. García López, R.J. Garczarczyk, M. Gasparyan, S. Gaug, M. Giglietto, N. Giordano, F. Gliwny, P. Godinović, N. Green, J.G. Green, D. Hadasch, D. Hahn, A. Heckmann, L. Herrera, J. Hoang, J. Hrupec, D. Hütten, M. Inada, T. Ishio, K. Iwamura, Y. Jiménez Martínez, I. Jormanainen, J. Jouvin, L. Karjalainen, M. Kerszberg, D. Kobayashi, Y. Kubo, H. Kushida, J. Lamastra, A. Lelas, D. Leone, F. Lindfors, E. Linhoff, L. Lombardi, S. López-Coto, R. López-Moya, M. López-Oramas, A. Machado de Oliveira Fraga, B. Maggio, C. Majumdar, P. Makariev, M. Mallamaci, M. Maneva, G. Manganaro, M. Mannheim, K. Maraschi, L. Mariotti, M. Martínez, M. Mazin, D. Menchiari, S. Mender, S. Mićanović, S. Miceli, D. Miener, T. Miranda, J.M. Mirzoyan, R. Molina, E. Moralejo, A. Morcuende, D. Moreno, V. Moretti, E. Nakamori, T. Neustroev, V. Nigro, C. Nilsson, K. Nishijima, K. Nozaki, S. Ohtani, Y. Oka, T. Otero-Santos, J. Paiano, S. Palatiello, M. Paneque, D. Paoletti, R. Paredes, J.M. Pavletić, L. Peñil, P. Persic, M. Pihet, M. Prada Moroni, P.G. Prandini, E. Institute for Cosmic Ray Research The University of Tokyo Kashiwanoha 5-1-5 Kashiwa Japan Max Planck Institut for Physics Föhringer Ring 6 Munich Germany INFN MAGIC Group INFN Sezione di Bari Dipartimento Interateneo di Fisica Università e del Politecnico di Bari BariI-70125 Italy Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima739-8526 Japan Street number Merate Italy Faculty of Electrical Engineering and Computing University of Zagreb Zagreb Croatia University of Trieste Department of Physics via Valerio 2 Trieste Italy INFN Sezione di Trieste via Valerio 2 Trieste Italy Instituto de Astrofísica de Canarias Dpto. de Astrofísica Universidad de La Laguna Tenerife La LagunaE-38200 Spain Università di Udine INFN Trieste UdineI-33100 Italy RomeI-00136 Italy ETH Zürich ZürichCH-8093 Switzerland Bellaterra BarcelonaE-08193 Spain The University of Tokyo Chiba Kashiwa277-8582 Japan Technische Universität Dortmund DortmundD-44221 Germany Zagreb10000 Croatia IPARCOS Institute EMFTEL Department Universidad Complutense de Madrid MadridE-28040 Spain URCA RJ Rio de Janeiro22290-180 Brazil Università di Padova INFN PadovaI-35131 Italy University of Lodz Faculty of Physics and Applied Informatics Department of Astrophysics Lodz90-236 Poland Università di Siena INFN Pisa SienaI-53100 Italy ZeuthenD-15738 Germany Max-Planck-Institut für Physik MünchenD-80805 Germany Instituto de Astrofísica de Andalucía-CSIC Glorieta de la Astronomía s/n Granada18008 Spain Università di Pisa INFN Pisa PisaI-56126 Italy Universitat de Barcelona ICCUB IEEC-UB BarcelonaE-08028 Spain Armenian MAGIC Group A. Alikhanyan National Science Laboratory Yerevan0036 Armenia Centro de Investigaciones Energéticas Medioambientales y Tecnológicas MadridE-28040 Spain INFN MAGIC Group INFN Sezione di Torino Università degli Studi di Torino TorinoI-10125 Italy Croatian MAGIC Group University o

Gamma-ray bursts (GRBs) are the most energetic phenomena in the Universe. Many aspects of GRB physics are still under debate, such as the origin of their gamma-ray emission above the GeV energy range. In 2019, MAGIC detected TeV gamma rays from the long GRB 190114C, whose emission can be well explained by synchrotron-self Compton emission by relativistic electrons. However, it is still unclear whether such a process is common in GRBs, given the reduced number of GRBs detected until now at the very high energies (VHE). GRB 201216C is a long GRB and is the second one detected by MAGIC in this energy range. After receiving the alert provided by Swift-BAT, MAGIC automatically slewed to the GRB position, starting observations 56 seconds after the GRB onset. In the offline analyses of the collected data, we confirmed the detection of gamma-ray emission with a significance above 5 sigma. Following measurements from optical facilities, the redshift of this GRB was estimated to be z = 1.1. This makes GRB 201216C the most distant object ever detected by ground-based gamma-ray telescopes. In this contribution we will show the analysis results of the MAGIC data, also in comparison with past detected GRBs in the same energy range. Finally, accounting for available multi-wavelength observations, we will comment on the possible origin of the VHE emission detected by MAGIC. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)

关键词： Germanium compounds

The structural, vibrational, and mechanical properties of jammed packings of deformable particles in three dimensions

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arXiv 2021年

作者： Wang, Dong Treado, John D. Boromand, Arman Norwick, Blake Murrell, Michael P. Shattuck, Mark D. O'Hern, Corey S. Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Department of Physics Yale University New HavenCT06520 United States Department of Biomedical Engineering Yale University New HavenCT06520 United States Systems Biology Institute Yale University West HavenCT06516 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Applied Physics Yale University New HavenCT06520 United States

We investigate the structural, vibrational, and mechanical properties of jammed packings of deformable particles with shape degrees of freedom in three dimensions (3D). Each 3D deformable particle is modeled as a surface-triangulated polyhedron, with spherical vertices whose positions are determined by a shape-energy function with terms that constrain the particle surface area, volume, and curvature, and prevent interparticle overlap. We show that jammed packings of deformable particles without bending energy possess low-frequency, quartic vibrational modes, whose number decreases with increasing asphericity and matches the number of missing contacts relative to the isostatic value. In contrast, jammed packings of deformable particles with non-zero bending energy are isostatic in 3D, with no quartic modes. We find that the contributions to the eigenmodes of the dynamical matrix from the shape degrees of freedom are significant over the full range of frequency and shape parameters for particles with zero bending energy. We further show that the ensembleaveraged shear modulus hGi scales with pressure P as hGi ∼ pβ, with β ≈ 0.75 for jammed packings of deformable particles with zero bending energy. In contrast, β ≈ 0.5 for packings of deformable particles with non-zero bending energy, which matches the value for jammed packings of soft, spherical particles with fixed shape. These studies underscore the importance of incorporating particle deformability and shape change when modeling the properties of jammed soft materials. © 2021, CC BY.

关键词： Degrees of freedom (mechanics)

Observation of current-induced switching in non-collinear antiferromagnetic IrMn3 by differential voltage measurements

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arXiv 2021年

作者： Arpaci, Sevdenur Lopez-Dominguez, Victor Shi, Jiacheng Sánchez-Tejerina, Luis Garesci, Francesca Wang, Chulin Yan, Xueting Sangwan, Vinod K. Grayson, Matthew Hersam, Mark C. Finocchio, Giovanni Amiri, Pedram Khalili Department of Electrical and Computer Engineering Northwestern University EvanstonIL60208 United States Graduate Program in Applied Physics Northwestern University EvanstonIL60208 United States Department of Mathematical and Computer Sciences Physical Sciences and Earth Sciences University of Messina Messina98166 Italy Department of Engineering University of Messina Messina98166 Italy Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States

There is accelerating interest in developing memory devices using antiferromagnetic (AFM) materials, motivated by the possibility for electrically controlling AFM order via spin-orbit torques, and its read-out via magnetoresistive effects. Recent studies have shown, however, that high current densities create non-magnetic contributions to resistive switching signals in AFM/heavy metal (AFM/HM) bilayers, complicating their interpretation. Here we introduce an experimental protocol to unambiguously distinguish current-induced magnetic and nonmagnetic switching signals in AFM/HM structures, and demonstrate it in IrMn3/Pt devices. A six-terminal double-cross device is constructed, with an IrMn3 pillar placed on one cross. The differential voltage is measured between the two crosses with and without IrMn3 after each switching attempt. For a wide range of current densities, reversible switching is observed only when write currents pass through the cross with the IrMn3 pillar, eliminating any possibility of non-magnetic switching artifacts. Micromagnetic simulations support our findings, indicating a complex domain-mediated switching process. © 2021, CC BY.

关键词： Binary alloys