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Nature Reviews Electrical Engineering 2025年 1-15页

作者： Wenhao Xue ( Tianfang Zhang ( Xiaonan Dong ( Xuezhi Ma ( Heng Xu ( Jiaqing Zhao ( Yuan Ma ( Department of Mechanical Engineering and Research Institute for Intelligent Wearable Systems The Hong Kong Polytechnic University Hong Kong S.A.R China Department of Rehabilitation Medicine First Affiliated Hospital College of Medicine Zhejiang University Hangzhou China Technology Innovation Center Zhe Jiang Key Laboratory of Intelligent Rehabilitation and Translational Neuroelectronics Hangzhou China Life and Health Institute China Resources Research Institute of Science and Technology Company Ltd Hong Kong S.A.R. China School of Biomedical Sciences LKS Faculty of Medicine The University of Hong Kong Hong Kong S.A.R. China A*STAR Quantum Innovation Centre (Q. InC) Agency for Science Technology and Research Singapore Singapore Institute of Materials Research and Engineering Agency for Science Technology and Research Singapore Singapore Department of Haptic Intelligence CVTE Guangzhou Shiyuan Electronics Company Ltd Guangzhou China Institute of Nuclear and New Energy Technology Tsinghua University Beijing China Research Center for Green and Smart Manufacturing PolyU-Daya Bay Technology and Innovation Research Institute Huizhou China

Digital information has permeated all aspects of life, and diverse forms of information exert a profound influence on social interactions and cognitive perceptions. In contrast to the flourishing of digital interaction devices for sighted users, the needs of blind and partially sighted users for digital interaction devices have not been adequately addressed. Current assistive devices often cause frustration in blind and partially sighted users owing to the limited efficiency and reliability of information delivery and the high cognitive load associated with their use. The expected rise in the prevalence of blindness and visual impairment due to global population ageing drives an urgent need for assistive devices that can deliver information effectively and non-visually, and thereby overcome the challenges faced by this community. This Perspective presents three potential directions in assistive device design: multisensory learning and integration; gestural interaction control; and the synchronization of tactile feedback with large-scale visual language models. Future trends in assistive devices for use by blind and partially sighted people are also explored, focusing on metrics for text delivery efficiency and the enhancement of image content delivery. Such devices promise to greatly enrich the lives of blind and partially sighted individuals in the digital age.

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Shock-induced HCNH+ abundance enhancement in the heart of the starburst galaxy NGC 253 unveiled by ALCHEMI

arXiv

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arXiv 2025年

作者： Gong, Y. Henkel, C. Bop, C.T. Mangum, J.G. Behrens, E. Du, F.J. Zhang, S.B. Martin, S. Menten, K.M. Harada, N. Bouvier, M. Tang, X.D. Tanaka, K. Viti, S. Yan, Y.T. Yang, W. Mao, R.Q. Quan, D.H. Purple Mountain Observatory Key Laboratory of Radio Astronomy Chinese Academy of Sciences 10 Yuanhua Road Nanjing210023 China Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Xinjiang Astronomical Observatory Chinese Academy of Sciences Urumqi830011 China - UMR 6251 RennesF-35000 France Nantes Université CNRS CEISAM UMR 6230 NantesF-44000 France National Radio Astronomy Observatory 520 Edgemont Road CharlottesvilleVA22903-2475 United States Department of Astronomy University of Virginia P. O. Box 400325 530 McCormick Road CharlottesvilleVA22904-4325 United States European Southern Observatory Alonso de Córdova 3107 Vitacura Santiago763-0355 Chile Joint ALMA Observatory Alonso de Córdova 3107 Vitacura Santiago763-0355 Chile National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Institute of Astronomy and Astrophysics Academia Sinica 11F of AS/NTU Astronomy-Mathematics Building No.1 Sec. 4 Roosevelt Road Taipei10617 Taiwan 2-21-1 Osawa Mitaka Tokyo181-1855 Japan Leiden Observatory Leiden University PO Box 9513 Leiden2300 RA Netherlands Key Laboratory of Radio Astronomy Chinese Academy of Sciences Urumqi830011 China Department of Physics Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kanagawa Yokohama223-8522 Japan School of Astronomy & Space Science Nanjing University 163 Xianlin Avenue Nanjing210023 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China

Context. Understanding the chemistry of molecular clouds is pivotal to elucidate star formation and galaxy evolution. As one of the important molecular ions, HCNH+ plays an important role in this chemistry. Yet, its behavior and significance under extreme conditions, such as in the central molecular zones (CMZs) of external galaxies, are still largely unexplored. Aims. We aim to reveal the physical and chemical properties of the CMZ in the starburst galaxy NGC 253 with multiple HCNH+ transitions to shed light on the molecule’s behavior under the extreme physical conditions of a starburst. Methods. We employ molecular line data including results for four rotational transitions of HCNH+ from the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) large program to investigate underlying physical and chemical processes. Results. Despite weak intensities, HCNH+ emission is widespread throughout NGC 253’s CMZ, which suggests that this molecular ion can effectively trace large-scale structures within molecular clouds. Using the quantum mechanical coupled states approximation, we computed rate coefficients for collisions of HCNH+ with para-H2 and ortho-H2 at kinetic temperatures up to 500 K. Using these coefficients in a non-LTE modeling framework and employing a Monte Carlo Markov chain analysis, we find that HCNH+ emission originates from regions with H2 number densities of ∼ 102.80 − 103.55 cm−3, establishing HCNH+ as a tracer of low-density environments. Our analysis reveals that most of the HCNH+ abundances in the CMZ of NGC 253 are higher than all reported values in the Milky Way. We performed static, photodissociation region (PDR), and shock modeling, and found that recurrent shocks could potentially account for the elevated HCNH+ abundances observed in this CMZ. Conclusions. We propose that the unexpectedly high HCNH+ abundances may result from chemical enhancement, primarily driven by the elevated gas temperatures and cosmic ray ionizatio

关键词： Cosmic rays

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A framework of biomarkers for brain aging: a consensus statement by the Aging Biomarker Consortium

Life Medicine

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Life Medicine 2023年第3期2卷 5页

作者： Aging Biomarker Consortium,Yu-Juan Jia Jun Wang Jun-Rong Ren Piu Chan Shengdi Chen Xiao-Chun Chen Jagadish K Chhetri Junhong Guo Qihao Guo Lingjing Jin Qiang Liu Wenlin Ma Zhiyong Mao Moshi Song Weihong Song Yi Tang Difei Wang Peijun Wang Lize Xiong Keqiang Ye Junjian Zhang Weiqi Zhang Xiaoqing Zhang Yunwu Zhang Zhanjun Zhang Zhuohua Zhang Jialin Zheng Guang-Hui Liu Yi Eve Sun Yan-Jiang Wang Gang Pei Department of Neurology and Centre for Clinical Neuroscience Daping Hospital Third Military Medical University Chongqing 400042 China Department of Neurology First Affiliated Hospital Shanxi Medical University Taiyuan 030001 China Department of Neurology and Centre for Clinical Neuroscience Daping Hospital Third Military Medical University Chongqing 400042 China National Clinical Research Center for Geriatric Diseases Xuanwu Hospital Capital Medical University Beijing 100053 China Department of Neurology and Institute of Neurology Ruijin Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200025 China Department of Neurology Union Hospital of Fujian Medical University Fuzhou 350001 China Department of Neurology First Affiliated Hospital Shanxi Medical University Taiyuan 030001 China Department of Gerontology Shanghai Sixth People?s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai 200233 China Department of Neurology and Neurological Rehabilitation Shanghai Disabled Persons? Federation Key Laboratory of Intelligent Rehabilitation Assistive Devices and Technologies Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center) Tongji University School of Medicine Shanghai 200092 China Institute on Aging and Brain Disorders The First Affiliated Hospital of USTC Hefei National Laboratory for Physical Sciences at the Microscale Division of Life Sciences and Medicine University of Science and Technology of China Hefei 230026 China Department of Neurology Institute of Neuroimmunology Tianjin Medical University General Hospital Tianjin 300052 China Department of Cardiology Shanghai Tongji Hospital Tongji University School of Medicine Shanghai 200092 China Shanghai Key Laboratory of Maternal Fetal Medicine Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital Frontier Science Center for Stem Cell Research Shanghai Key Laboratory of Signaling and Disease Research School of Lif

China and the world are facing severe population aging and an increasing burden of age-related diseases. Aging of the brain causes major age-related brain diseases, such as neurodegenerative diseases and stroke. Identifying biomarkers for the effective assessment of brain aging and establishing a brain aging assessment system could facilitate the development of brain aging intervention strategies and the effective prevention and treatment of aging-related brain diseases. Thus, experts from the Aging Biomarker Consortium (ABC) have combined the latest research results and practical experience to recommend brain aging biomarkers and form an expert consensus, aiming to provide a basis for assessing the degree of brain aging and conducting brain-aging-related research with the ultimate goal of improving the brain health of elderly individuals in both China and the world.

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Scintillation Arc from FRB 20220912A

arXiv

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arXiv 2023年

作者： Wu, Zi-Wei Main, Robert A. Zhu, Wei-Wei Zhang, Bing Jiang, Peng Niu, Jia-Rui Han, Jin-Lin Li, Di Lee, Ke-Jia Li, Dong-Zi Yang, Yuan-Pei Wang, Fa-Yin Luo, Rui Wang, Pei Niu, Chen-Hui Xu, Heng Wang, Bo-Jun Wang, Wei-Yang Zhang, Yong-Kun Feng, Yi Zhou, De-Jiang Xu, Yong-Hua Deng, Can-Min Zhu, Yu-Hao National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 Bonn53121 Germany Institute for Frontier in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Nevada Center for Astrophysics Department of Physics and Astronomy University of Nevada Las VegasNV89154 United States CAS Key Laboratory of FAST National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Astronomy University of Chinese Academy of Sciences Beijing China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-Natal Durban4000 South Africa Department of Astronomy Peking University Beijing100871 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Cahill Center for Astronomy and Astrophysics California Institute of Technology MC 249-17 PasadenaCA91125 United States South-Western Institute For Astronomy Research Yunnan University Yunnan650504 China School of Astronomy and Space Science Nanjing University Nanjing210093 China Ministry of Education China CSIRO Space and Astronomy PO Box 76 EppingNSW1710 Australia Department of Astronomy School of Physics and Materials Science Guangzhou University Guangzhou510006 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Guangxi Key Laboratory for Relativistic Astrophysics Department of Physics Guangxi University Nanning530004 China

We present the interstellar scintillation analysis of fast radio burst (FRB) 20220912A during its extremely active episode in 2022 using data from the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). We detect a scintillation arc in the FRB’s secondary spectrum, which describes the power in terms of the scattered FRB signals’ time delay and Doppler shift. The arc indicates that the scintillation is caused by a highly localized region. Our analysis favors a Milky Way origin of the ionized interstellar medium (IISM) for the localized scattering medium but cannot rule out a host galaxy origin. We present our method for detecting the scintillation arc, which can be applied generally to sources with irregularly spaced bursts or pulses. These methods could help shed light on the complex interstellar environment surrounding the FRBs and in our Galaxy. Copyright © 2023, The Authors. All rights reserved.

关键词： Scintillation

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Young O-rich Stars Migrated from the Outer Disc: Imprints of Sagittarius Accretion Event

arXiv

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arXiv 2023年

作者： Sun, Tiancheng Bi, Shaolan Chen, Xunzhou Chen, Yuqin Lu, Yuxi Liu, Chao Buck, Tobias Zhang, Xianfei Li, Tanda Li, Yaguang Wu, Yaqian Ge, Zhishuai Ye, Lifei Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China School of Physics and Astronomy Beijing Normal University Beijing100875 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China CAS Key Laboratory of Optical Astronomy National Astronomical Observatories Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China American Museum of Natural History Central Park West ManhattanNY10024 United States Department of Astronomy The Ohio State University 140 W 18th Ave ColumbusOH43210 United States The Ohio State University 191 W. Woodruff Ave. ColumbusOH43210 United States Universität Heidelberg Interdisziplinäres Zentrum für Wissenschaftliches Rechnen Im Neuenheimer Feld 205 HeidelbergD-69120 Germany Universität Heidelberg Zentrum für Astronomie Institut für Theoretische Astrophysik Albert-Ueberle-Straβe 2 HeidelbergD-69120 Germany Institute for Astronomy University of Hawai’i 2680 Woodlawn Drive HonoluluHI96822 United States Beijing Planetarium Beijing Academy of Science and Technology Beijing100044 China

The Milky Way underwent significant transformations in its early history, characterised by violent mergers and satellite galaxy accretion. However, recent observations reveal notable star formation events over the past 4 Gyr, likely triggered by perturbations from the Sagittarius dwarf galaxy. Here, we present chemical signatures of this accretion event, using the [Fe/H] and [O/Fe] ratios of thin disc stars. In the normalised age-metallicity plane, we identify a discontinuous V-shape structure at zmax Copyright © 2023, The Authors. All rights reserved.

关键词： Oxygen

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FAST Observations of FRB 20220912A: Burst Properties and Polarization Characteristics

arXiv

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arXiv 2023年

作者： Zhang, Yong-Kun Li, Di Zhang, Bing Cao, Shuo Feng, Yi Wang, Wei-Yang Qu, Yuanhong Niu, Jia-Rui Zhu, Wei-Wei Han, Jin-Lin Jiang, Peng Lee, Ke-Jia Li, Dong-Zi Luo, Rui Niu, Chen-Hui Tsai, Chao-Wei Wang, Pei Wang, Fa-Yin Wu, Zi-Wei Xu, Heng Yang, Yuan-Pei Zhang, Jun-Shuo Zhou, De-Jiang Zhu, Yu-Hao National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China University of Chinese Academy of Sciences Beijing100049 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-Natal Durban4000 South Africa Nevada Center for Astrophysics University of Nevada Las VegasNV89154 United States Department of Physics and Astronomy University of Nevada Las VegasNV89154 United States Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Department of Astronomy Peking University Beijing100871 China CAS Key Laboratory of FAST National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Cahill Center for Astronomy and Astrophysics MC 249-17 California Institute of Technology PasadenaCA91125 United States CSIRO Space and Astronomy PO Box 76 EppingNSW1710 Australia Department of Astronomy School of Physics and Materials Science Guangzhou University Guangzhou510006 China School of Astronomy and Space Science Nanjing University Nanjing210093 China Ministry of Education China South-Western Institute for Astronomy Research Yunnan University Yunnan Kunming650504 China Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China

We report the observations of FRB 20220912A using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We conducted 17 observations totaling 8.67 hours and detected a total of 1076 bursts with an event rate up to 390 hr−1. The cumulative energy distribution can be well described using a broken power-law function with the lower and higher-energy slopes of −0.38 ± 0.02 and −2.07 ±0.07, respectively. We also report the L band (1 − 1.5 GHz) spectral index of the synthetic spectrum of FRB 20220912A bursts, which is −2.6 ± 0.21. The average rotation measure (RM) value of the bursts from FRB 20220912A is −0.08 ±5.39 rad m−2, close to 0 rad m−2 and maintain relatively stable over two months. Most bursts have nearly 100% linear polarization. About 45% of the bursts have circular polarization with SNR > 3, and the highest circular polarization degree can reach 70%. Our observations suggest that FRB 20220912A is located in a relatively clean local environment with complex circular polarization characteristics. These various behaviors imply that the mechanism of circular polarization of FRBs likely originates from an intrinsic radiation mechanism, such as coherent curvature radiation or inverse Compton scattering inside the magnetosphere of the FRB engine source (e.g. a magnetar). © 2023, CC BY.

关键词： Circular polarization

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Towards the next generation nanorobots

Next Nanotechnology

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Next Nanotechnology 2023年 2卷

作者： Guoxiang Chen Fenyang Zhu Alexandra S.J. Gan Brij Mohan Krishna K. Dey Kailiang Xu Gaoshan Huang Jizhai Cui Alexander A. Solovev Yongfeng Mei Department of Materials Science & State Key Laboratory of Molecular Engineering of Polymers Fudan University Shanghai 200433 PR China Centro de Quimica Estrutural Institute of Molecular Sciences Instituto Superior Tecnico Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portugal Discipline of Physics Indian Institute of Technology Gandhinagar Gandhinagar Gujarat 382355 India Center for Biomedical Engineering School of Information Science and Technology Fudan University Shanghai 200433 PR China International Institute of Intelligent Nanorobots and Nanosystems Fudan University Shanghai 200433 PR China Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Perception Fudan University Shanghai 200433 PR China Yiwu Research Institute of Fudan University Yiwu 322000 Zhejiang PR China

Nanorobots with advanced capabilities that can accomplish various tasks have been the focus of significant research interests. Nanorobots can self-propel in different trajectories, be guided using external fields, and interact with objects and the environment. In recent years, various fabrication techniques, such as physical, chemical, microfluidic, and self-assembly methods, have been employed to integrate specific functions. Microfluidic platforms are utilized to encapsulate individual reactions and reaction networks, providing an experimental testbed system for designing the next generation of nanorobots. Due to significant progress in the field, man-made nanobots have been applied for a wide variety of operations. Today, a convergence between biomedical nanoparticles and nanorobots is apparent. This review discusses the next generation of nanorobots, the range of their fabrication techniques, and introduces integrated functions for bio-applications.

关键词： Nanorobots Nanomotors Motion control Autonomous propulsion Microfluidics Bioapplications

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RRAT J1913+1330: an extremely variable and puzzling pulsar

arXiv

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arXiv 2023年

作者： Zhang, Songbo B. Geng, J.J. Wang, J.S. Yang, X. Kaczmarek, J. Tang, Z.F. Johnston, S. Hobbs, G. Manchester, R. Wu, X.F. Jiang, P. Huang, Y.F. Zou, Y.C. Dai, Z.G. Zhang, B. Li, D. Yang, Y.P. Dai, S. Chang, C.M. Pan, Z.C. Lu, J.G. Wei, J.J. Li, Y. Wu, Q.W. Qian, L. Wang, P. Wang, S.Q. Feng, Y. Staveley-Smith, L. Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China Max-Planck-Institut für Kernphysik Saupfercheckweg 1 HeidelbergD-69117 Germany School of Astronomy and Space Sciences University of Science and Technology of China Hefei230026 China CSIRO Space and Astronomy EppingNSW1710 Australia Department of Computer Science Math Physics & Statistics University of British Columbia KelownaBCV1V 1V7 Canada National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China CAS Key laboratory of FAST National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Astronomy and Space Science Nanjing University Nanjing210023 China School of Physics Huazhong University of Science and Technology Wuhan430074 China Department of Astronomy University of Science and Technology of China Hefei230026 China Department of Physics and Astronomy University of Nevada Las VegasNV89154 United States Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China University of Chinese Academy of Sciences Beijing100049 China South-Western Institute for Astronomy Research Yunnan University Kunming650504 China School of Science Western Sydney University Locked Bag 1797 PenrithNSW2751 Australia Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Xinjiang Astronomical Observatory Chinese Academy of Sciences Science 1-Street Urumqi Xinjiang830011 China International Centre for Radio Astronomy Research University of Western Australia CrawleyWA6009 Australia

Rotating Radio Transients (RRATs) are neutron stars that emit sporadic radio bursts. We detected 1955 single pulses from RRAT J1913+1330 using the 19-beam receiver of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). These pulses were detected in 19 distinct clusters, with 49.4% of them occurring with a waiting time of one rotation period. The energy distribution of these individual pulses exhibited a wide range, spanning three orders of magnitude, reminiscent of repeating fast radio bursts (FRBs). Furthermore, we observed abrupt variations in pulse profile, width, peak flux, and fluence between adjacent sequential pulses. These findings suggest that this RRAT could be interpreted as a pulsar with extreme pulse-to-pulse modulation. The presence of sequential pulse trains during active phases, along with significant pulse variations in profile, fluence, flux, and width, should be intrinsic to a subset of RRATs. Our results indicate that J1913+1330 represents a peculiar source that shares certain properties with populations of nulling pulsars, giant pulses, and FRBs from different perspectives. The dramatic pulse-to-pulse variation observed in J1913+1330 could be attributed to unstable pair creation above the polar cap region and the variation of the site where streaming pairs emit coherently. Exploring a larger sample of RRATs exhibiting similar properties to J1913+1330 has the potential to significantly advance our understanding of pulsars, RRATs, and FRBs. Copyright © 2023, The Authors. All rights reserved.

关键词： Pulsars

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The FAST HI 21-cm absorption blind survey. II. – Statistic Exploration for Associated and Intervening Systems

arXiv

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arXiv 2024年

作者： Hu, Wenkai Wang, Yougang Li, Yichao Pen, Ue-Li Wang, Jie Jing, Yingjie Zhu, Ming Zhang, Xin Yang, Wenxiu Xu, Yidong Xu, Chen Chen, Jingze Zheng, Zheng Li, Di Chen, Xuelei Chen, Qingze Wu, Fengquan Department of Physics and Astronomy University of the Western Cape Robert Sobukwe Road Bellville7535 South Africa Australia National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences A20 Datun Road Chaoyang District Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China College of Sciences Northeastern University Shenyang110819 China Institute of Astronomy and Astrophysics Academia Sinica Astronomy-Mathematics Building No. 1 Sec. 4 Roosevelt Road Taipei10617 Taiwan Canadian Institute for Theoretical Astrophysics University of Toronto 60 Saint George Street TorontoONM5S 3H8 Canada Canadian Institute for Advanced Research 180 Dundas St West TorontoONM5G 1Z8 Canada Dunlap Institute for Astronomy and Astrophysics University of Toronto 50 St George Street TorontoONM5S 3H4 Canada Perimeter Institute of Theoretical Physics 31 Caroline Street North WaterlooONN2L 2Y5 Canada Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China Department of Astronomy Tsinghua Univerisity 30 Shuangqing Road Beijing100084 China Guizhou Radio Astronomical Observatory Guizhou University Guiyang550000 China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Shenyang110819 China Northeastern University Shenyang110819 China

We present an extragalactic HI 21-cm absorption lines catalog from a blind search at z ≤ 0.35, using drift-scan data collected in 1325.6 hours by the ongoing Commensal Radio Astronomy FasT Survey (CRAFTS) and FAST All Sky HI Survey (FASHI), which spans a sky area of 6072.0 deg2 and covers 84533 radio sources with a flux density greater than 12 mJy. 14 previously identified HI absorbers and 20 newly discovered HI absorbers were detected, comprising 15 associated systems, 10 intervening systems, and 9 systems with undetermined classifications. Through spectral stacking, the mean peak optical path, mean velocity-integrated optical path, mean FWHM and mean HI column density are measured to be 0.47 and 0.30;27.19 and 4.36 km s−1;42.61 and 9.33 km s−1;0.49 and 0.08 Ts× 1020cm−2K−1, for the associated and intervening samples, respectively. Statistical analysis also reveals that associated systems tend to be hosted by red (g − r >0.7) galaxies at lower redshifts, whereas galaxies hosting intervening HI absorption are typically found at higher redshifts and are of a bluer (g−r ≤0.7) type. A noticeable difference is observed in the positions of foregrounds, backgrounds of intervening systems, and high-redshift and low-redshift associated systems on the WISE color-color diagram. All identified foreground sources in our sample have W1-W2 magnitudes below 0.8, suggesting no Active Galactic Nuclei (AGN). In contrast, backgrounds of intervening systems tend to have W1-W2 magnitudes above 0.8, indicating AGN presence. For associated absorption, most low-redshift (z ≤0.5) systems show W1-W2 values below 0.8, while higher-redshift associated absorption (z >0.5) displays a broader range of W1-W2 values. Copyright © 2024, The Authors. All rights reserved.

关键词： Moon

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Insight-HXMT and GECAM-C observations of the brightest-of-all-time GRB 221009A

arXiv

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arXiv 2023年

作者： An, Zheng-Hua Antier, S. Bi, Xing-Zi Bu, Qing-Cui Cai, Ce Cao, Xue-Lei Camisasca, Anna-Elisa Chang, Zhi Chen, Gang Chen, Li Chen, Tian-Xiang Chen, Wen Chen, Yi-Bao Chen, Yong Chen, Yu-Peng Coughlin, Michael W. Cui, Wei-Wei Dai, Zi-Gao Hussenot-Desenonges, T. Du, Yan-Qi Du, Yuan-Yuan Du, Yun-Fei Fan, Cheng-Cheng Frontera, Filippo Gao, He Gao, Min Ge, Ming-Yu Gong, Ke Gu, Yu-Dong Guan, Ju Guo, Dong-Ya Guo, Zhi-Wei Guidorzi, Cristiano Han, Da-Wei He, Jian-Jian He, Jun-Wang Hou, Dong-Jie Huang, Yue Huo, Jia Ji, Zhen Jia, Shu-Mei Jiang, Wei-Chun Kann, David Alexander Klotz, A. Kong, Ling-Da Lan, Lin Li, An Li, Bing Li, Chao-Yang Li, Cheng-Kui Li, Gang Li, Mao-Shun Li, Ti-Pei Li, Wei Li, Xiao-Bo Li, Xin-Qiao Li, Xu-Fang Li, Yan-Guo Li, Zheng-Wei Liang, Jing Liang, Xiao-Hua Liao, Jin-Yuan Lin, Lin Liu, Cong-Zhan Liu, He-Xin Liu, Hong-Wei Liu, Jia-Cong Liu, Xiao-Jing Liu, Ya-Qing Liu, Yu-Rong Lu, Fang-Jun Lu, Hong Lu, Xue-Feng Luo, Qi Luo, Tao Ma, Bin-Yuan Ma, Fu-Li Ma, Rui-Can Ma, Xiang Maccary, Romain Mao, Ji-Rong Meng, Bin Nie, Jian-Yin Orlandini, Mauro Ou, Ge Peng, Jing-Qiang Peng, Wen-Xi Qiao, Rui Qu, Jin-Lu Ren, Xiao-Qin Shi, Jing-Yan Shi, Qi Song, Li-Ming Song, Xin-Ying Su, Ju Sun, Gong-Xing Sun, Liang Sun, Xi-Lei Tan, Wen-Jun Tan, Ying Tao, Lian Tuo, You-Li Turpin, Damien Wang, Jin-Zhou Wang, Chen Wang, Chen-Wei Wang, Hong-Jun Wang, Hui Wang, Jin Wang, Ling-Jun Wang, Peng-Ju Wang, Ping Wang, Wen-Shuai Wang, Xiang-Yu Wang, Xi-Lu Wang, Yu-Sa Wang, Yue Wen, Xiang-Yang Wu, Bo-Bing Wu, Bai-Yang Wu, Hong Xiao, Sheng-Hui Xiao, Shuo Xiao, Yun-Xiang Xie, Sheng-Lun Xiong, Shao-Lin Xiong, Sen-Lin Xu, Dong Xu, He Xu, Yan-Jun Xu, Yan-Bing Xu, Ying-Chen Xu, Yu-Peng Xue, Wang-Chen Yang, Sheng Yang, Yan-Ji Yang, Zi-Xu Ye, Wen-Tao Yi, Qi-Bin Yi, Shu-Xu Yin, Qian-Qing You, Yuan Yu, Yun-Wei Yu, Wei Yu, Wen-Hui Zeng, Ming Zhang, Bing Zhang, Bin-Bin Zhang, Da-Li Zhang, Fan Zhang, Hong-Mei Zhang, Juan Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences 19B Yuquan Road Beijing100049 China Institut für Astronomie und Astrophysik Kepler Center for Astro and Particle Physics Eberhard Karls Universität Sand 1 Tübingen72076 Germany College of Physics Hebei Key Laboratory of Photophysics Research and Application Hebei Normal University Hebei Shijiazhuang050024 China Department of Physics and Earth Science University of Ferrara Via Saragat 1 Ferrara44122 Italy Department of Astronomy Beijing Normal University Beijing100875 China CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei230026 China Department of Astronomy Tsinghua University Beijing100084 China Southwest Jiaotong University Chengdu610092 China INAF Osservatorio di Astrofisica e Scienza dello Spazio di Bologna Via Piero Gobetti 101 Bologna40129 Italy University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China College of physics Sciences Technology Hebei University No. 180 Wusi Dong Road Lian Chi District Hebei Baoding071002 China INFN - Sezione di Ferrara Via Saragat 1 Ferrara44122 Italy Physics and Space Science College China West Normal University China Yunnan Observatories Chinese Academy of Sciences Yunnan Province Kunming650011 China Key Laboratory of Space Astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China School of Astronomy and Space Science Nanjing University Nanjing210093 China School of Physics and Optoelectronics Xiangtan University Yuhu District Hunan Xiangtan411105 China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal University Guiyang550001 China Institute of Astrophysics Central China Normal University Wuhan430079 China Nevada Center for Astrophysics Department of Physics and Astronomy University of

GRB 221009A is the brightest gamma-ray burst ever detected since the discovery of this kind of energetic explosions. However, an accurate measurement of the prompt emission properties of this burst is very challenging due to its exceptional brightness. With joint observations of Insight-HXMT and GECAM-C, we made an unprecedentedly accurate measurement of the emission during the first ∼1800 s of GRB 221009A, including its precursor, main emission (ME, which dominates the burst in flux), flaring emission and early afterglow, in the hard X-ray to soft gamma-ray band from ∼ 10 keV to ∼ 6 MeV. Based on the GECAM-C unsaturated data of the ME, we measure a record-breaking isotropic equivalent energy (Eiso) of ∼ 1.5 × 1055 erg, which is about eight times the total rest-mass energy of the Sun. The early afterglow data require a significant jet break between 650 s and 1100 s, most likely at ∼ 950 s from the afterglow starting time TAG, which corresponds to a jet opening angle of ∼ 0.7◦ (ηγn)1/8, where n is the ambient medium density in units of cm−3 and ηγ is the ratio between γ-ray energy and afterglow kinetic energy. The beaming-corrected total γ-ray energy Eγ is ∼ 1.15 × 1051 (ηγn)1/4 erg, which is typical for long GRBs. These results suggest that this GRB may have a special central engine, which could launch and collimate a very narrowly beamed jet with an ordinary energy budget, leading to exceptionally luminous gamma-ray radiation per unit solid angle. Alternatively, more GRBs might have such a narrow and bright beam, which are missed by an unfavorable viewing angle or have been detected without distance measurement. Copyright © 2023, The Authors. All rights reserved.

关键词： Gamma rays

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