In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunit...In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunity to study the physics in the extreme environments.The enhanced X-ray Timing and Polarimetry mission(eXTP),planned to be launched in 2030,has several key advantages,including advanced polarimetry,high sensitivity&large effective area,and wide energy range coverage,which make it a groundbreaking project in high-energy astrophysics.In this article,we briefly introduce the potential time-domain and multi-messenger targets for eXTP,including gravitational-wave(GW)counterparts,gamma-ray bursts(GRBs),magnetars and fast radio bursts(FRBs),tidal disruption events(TDEs),supernovae,high energy neutrinos and TeV active galactic nucleus(AGNs),and so on.We discuss the advantages of future eXTP observations for detecting these sources,their detection capabilities,the abilities to distinguish theoretical models,and their applications in gravity and cosmology.展开更多
Gravitational wave detection has ushered in a new era of observing the universe, providing humanity with a novel window for cosmic cognition. This theoretical study systematically traces the developmental trajectory o...Gravitational wave detection has ushered in a new era of observing the universe, providing humanity with a novel window for cosmic cognition. This theoretical study systematically traces the developmental trajectory of gravitational wave detection technology and delves into its profound impact on cosmological research. From Einstein’s prediction in general relativity to LIGO’s groundbreaking discovery, the article meticulously delineates the key theoretical and technological milestones in gravitational wave detection, with particular emphasis on elucidating the principles and evolution of core detection technologies such as laser interferometers. The research thoroughly explores the theoretical application value of gravitational waves in verifying general relativity, studying the physics of compact celestial bodies like black holes and neutron stars, and precisely measuring cosmological parameters. The article postulates that gravitational wave observations may offer new research perspectives for addressing cosmological conundrums such as dark matter, dark energy, and early universe evolution. The study also discusses the scientific prospects of combining gravitational wave observations with electromagnetic waves, neutrinos, and other multi-messenger observations, analyzing the potential value of this multi-messenger astronomy in deepening cosmic cognition. Looking ahead, the article examines cutting-edge concepts such as space-based gravitational wave detectors and predicts potential developmental directions for gravitational wave astronomy. This research not only elucidates the theoretical foundations of gravitational wave detection technology but also provides a comprehensive theoretical framework for understanding the far-reaching impact of gravitational waves on modern cosmology.展开更多
The multi-messenger observation of coalescing compact binary systems promises great scientific treasure.However,synthesising observations from both gravitational wave and electromagnetic channels remains challenging.I...The multi-messenger observation of coalescing compact binary systems promises great scientific treasure.However,synthesising observations from both gravitational wave and electromagnetic channels remains challenging.In the context of the day-to-week long emission from a macronova,the binary neutron star merger GW170817 remains the only event with successful electromagnetic followup.In this manuscript,we explore the possibility of using the early stage X-ray afterglow to search for the electromagnetic counterpart of a gravitational wave event.Two algorithms,the simple and straightforward sequential observation(SO)and the step-wise optimizing local optimization are considered and applied to some simulated events.We consider the WXT from the proposed Einstein Probe as a candidate X-ray telescope,which has a very wide field of view of 3600 deg^(2).Benefiting from the large field of view and high sensitivity,we find that the SO algorithm not only is easy to implement,but also promises a good chance of actual detection.展开更多
Dark photons,as a minimal extension of the Standard Model through an additional Abelian gauge group,may propagate relativistically across the galaxy,originating from dark matter decay or annihilation,thereby contribut...Dark photons,as a minimal extension of the Standard Model through an additional Abelian gauge group,may propagate relativistically across the galaxy,originating from dark matter decay or annihilation,thereby contributing to a galactic dark photon background.The generation of dark photons typically favors certain polarization modes,which are dependent on the interactions between dark matter and dark photons.We introduce a framework in which a resonant cavity is utilized to detect and differentiate these polarizations,leveraging the daily variation in expected signals due to the anisotropic distribution of dark photons and the rotation of the Earth.We conduct an experimental search using superconducting radio-frequency cavities,noted for their exceptionally high quality factors,proving them to be effective telescopes for observing galactic dark photons.This approach establishes the most stringent limits yet on the kinetic mixing coefficient between dark photons and electromagnetic photons,thereby unveiling a novel avenue for the indirect search for dark matter via multi-messenger astronomy.展开更多
The Wide Field Survey Telescope(WFST) is a dedicated photometric surveying facility being built jointly by University of Science and Technology of China(USTC) and the Purple Mountain Observatory(PMO). It is equipped w...The Wide Field Survey Telescope(WFST) is a dedicated photometric surveying facility being built jointly by University of Science and Technology of China(USTC) and the Purple Mountain Observatory(PMO). It is equipped with a 2.5-meter diameter primary mirror, an active optics system, and a mosaic CCD camera with 0.73 gigapixels on the primary focal plane for highquality image capture over a 6.5-square-degree field of view. The installation of WFST near the summit of Saishiteng mountain in the Lenghu region is scheduled in summer of 2023, and the operation is planned to start three months later. WFST will scan the northern sky in four optical bands(u, g, r and i) at cadences from hourly/daily in the deep high-cadence survey(DHS) program, to semi-weekly in the wide field survey(WFS) program. During a photometric night, a nominal 30 s exposure in the WFS program will reach a depth of 22.27, 23.32, 22.84, and 22.31(AB magnitudes) in these four bands, respectively, allowing for the detection of a tremendous amount of transients in the low-z universe and a systematic investigation of the variability of Galactic and extragalactic objects. In the DHS program, intranight 90 s exposures as deep as 23(u) and 24 mag(g), in combination with target of opportunity follow-ups, will provide a unique opportunity to explore energetic transients in demand for high sensitivities, including the electromagnetic counterparts of gravitational wave events, supernovae within a few hours of their explosions,tidal disruption events and fast, luminous optical transients even beyond redshift of unity. In addition, the final 6-year co-added images, anticipated to reach g■25.8 mag in WFS or 1.5 mags deeper in DHS, will be of fundamental importance to general Galactic and extragalactic science. The highly uniform legacy surveys of WFST will serve as an indispensable complement to those of the Vera C. Rubin Observatory's Legacy Survey of Space and Time(LSST) that monitors the southern sky.展开更多
In the first part of this Chapter the present state of knowledge from the observations of cosmic rays between 10^(13) and 10^(20) eV is summarized.This is not intended to be a complete review,but rather a broad overvi...In the first part of this Chapter the present state of knowledge from the observations of cosmic rays between 10^(13) and 10^(20) eV is summarized.This is not intended to be a complete review,but rather a broad overview of the relevant processes involving cosmic rays,including the astrophysical environments in which they take place.This overview mainly concerns experimental results and phenomenological aspects of their interpretation,therefore experiments’description is not given but references to the vast bibliography are provided in the text.Some attempt is made to address the most popular explanations offered by theoretical models.The second part is devoted to the description of the LHAASO performance and of its capability to provide a response to several open questions,still unanswered,concerning cosmic rays above 10^(13) eV,highlighting which major steps forward in this field could be taken from LHAASO observations.展开更多
基金supported by China’s Space Origins Exploration Programsupport from the Chinese Academy of Sciences (Grant No.E32983U810)+13 种基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB0550300)the National Natural Science Foundation of China (Grant No.12325301)supported by the National Natural Science Foundation of China (Grant Nos.12233002,and 12041306)the National SKA Program of China (Grant No.2020SKA0120300)the National Key R&D Program of China (Grant No.2021YFA0718500)the support from the Xinjiang Tianchi Programsupported by the National Natural Science Foundation of China (Grant No.12333007)the International Partnership Program of the Chinese Academy of Sciences (Grant No.113111KYSB20190020)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA15020100)supported by the Beijing Municipal Natural Science Foundation (Grant No.1242032)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No.2022056)supported by the National Key Research and Development Program of China (Grant Nos.2022YFC2205201,and 2020YFC2201400)funding by the European Union-Next Generation EU RFF M4C2 1.1 PRIN 2022 project “2022RJLWHN URKA”INAF 2023 Theory Grant Ob Fu 1.05.23.06.06 “Understanding R-process & Kilonovae Aspects (URKA)”.
文摘In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunity to study the physics in the extreme environments.The enhanced X-ray Timing and Polarimetry mission(eXTP),planned to be launched in 2030,has several key advantages,including advanced polarimetry,high sensitivity&large effective area,and wide energy range coverage,which make it a groundbreaking project in high-energy astrophysics.In this article,we briefly introduce the potential time-domain and multi-messenger targets for eXTP,including gravitational-wave(GW)counterparts,gamma-ray bursts(GRBs),magnetars and fast radio bursts(FRBs),tidal disruption events(TDEs),supernovae,high energy neutrinos and TeV active galactic nucleus(AGNs),and so on.We discuss the advantages of future eXTP observations for detecting these sources,their detection capabilities,the abilities to distinguish theoretical models,and their applications in gravity and cosmology.
文摘Gravitational wave detection has ushered in a new era of observing the universe, providing humanity with a novel window for cosmic cognition. This theoretical study systematically traces the developmental trajectory of gravitational wave detection technology and delves into its profound impact on cosmological research. From Einstein’s prediction in general relativity to LIGO’s groundbreaking discovery, the article meticulously delineates the key theoretical and technological milestones in gravitational wave detection, with particular emphasis on elucidating the principles and evolution of core detection technologies such as laser interferometers. The research thoroughly explores the theoretical application value of gravitational waves in verifying general relativity, studying the physics of compact celestial bodies like black holes and neutron stars, and precisely measuring cosmological parameters. The article postulates that gravitational wave observations may offer new research perspectives for addressing cosmological conundrums such as dark matter, dark energy, and early universe evolution. The study also discusses the scientific prospects of combining gravitational wave observations with electromagnetic waves, neutrinos, and other multi-messenger observations, analyzing the potential value of this multi-messenger astronomy in deepening cosmic cognition. Looking ahead, the article examines cutting-edge concepts such as space-based gravitational wave detectors and predicts potential developmental directions for gravitational wave astronomy. This research not only elucidates the theoretical foundations of gravitational wave detection technology but also provides a comprehensive theoretical framework for understanding the far-reaching impact of gravitational waves on modern cosmology.
基金Guangdong Major Project of Basic and Applied Basic Research(Contract No.2019B030302001)the National Natural Science Foundation of China(Grant No.11703098)+3 种基金support by the Strategic Pioneer Program on Space Science,Chinese Academy of Sciences(grant Nos.XDA15052100,XDA15310300)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB23040100)supported by the Science and Technology Facilities Council(Grant No.ST/L000946/1)funded by the Science and Technology Facilities Council UK grant no.ST/R002770/1。
文摘The multi-messenger observation of coalescing compact binary systems promises great scientific treasure.However,synthesising observations from both gravitational wave and electromagnetic channels remains challenging.In the context of the day-to-week long emission from a macronova,the binary neutron star merger GW170817 remains the only event with successful electromagnetic followup.In this manuscript,we explore the possibility of using the early stage X-ray afterglow to search for the electromagnetic counterpart of a gravitational wave event.Two algorithms,the simple and straightforward sequential observation(SO)and the step-wise optimizing local optimization are considered and applied to some simulated events.We consider the WXT from the proposed Einstein Probe as a candidate X-ray telescope,which has a very wide field of view of 3600 deg^(2).Benefiting from the large field of view and high sensitivity,we find that the SO algorithm not only is easy to implement,but also promises a good chance of actual detection.
基金National Key Research and Development Program of China(2020YFC2201501)Yifan Chen was supported by VILLUM FONDEN(37766)+4 种基金Danish Research Foundation,and under the European Union’s H2020 ERC Advanced Grant“Black holes:gravitational engines of discovery”grant agreement(Gravitas–101052587)European Consortium for Astroparticle Theory in the form of an Exchange Travel Grant,and by FCT(Fundação para a Ciência e Tecnologia I.P,Portugal)(2022.01324.PTDC)Jing Shu was supported by the National Natural Science Foundation of China(12025507,12450006,and.12150015)Peking University under startup Grant(7101302974)State Key Laboratory of Nuclear Physics and Technology,Peking University(NPT2024ZX01).
文摘Dark photons,as a minimal extension of the Standard Model through an additional Abelian gauge group,may propagate relativistically across the galaxy,originating from dark matter decay or annihilation,thereby contributing to a galactic dark photon background.The generation of dark photons typically favors certain polarization modes,which are dependent on the interactions between dark matter and dark photons.We introduce a framework in which a resonant cavity is utilized to detect and differentiate these polarizations,leveraging the daily variation in expected signals due to the anisotropic distribution of dark photons and the rotation of the Earth.We conduct an experimental search using superconducting radio-frequency cavities,noted for their exceptionally high quality factors,proving them to be effective telescopes for observing galactic dark photons.This approach establishes the most stringent limits yet on the kinetic mixing coefficient between dark photons and electromagnetic photons,thereby unveiling a novel avenue for the indirect search for dark matter via multi-messenger astronomy.
基金supported by the Cyrus Chun Ying Tang Foundationsthe Major Science and Technology Project of Qinghai Province(Grant No.2019ZJ-A10)+4 种基金the 111 Project for“Observational and Theoretical Research on Dark Matter and Dark Energy”(Grant No.B23042)the National Natural Science Foundation of China(Grant Nos.11833007,12073078,12173088,12192221,12192224,12233008,12273036,and 12273113)the Frontier Scientific Research Program of Deep Space Exploration Laboratory(Grant No.2022-QYKYJH-HXYF-012)the support from the USTC Research Funds of the Double First-Class Initiative(Grant No.YD2030002009)Project for Young Scientists in Basic Research of the Chinese Academy of Sciences(Grant No.YSBR-061),respectively。
文摘The Wide Field Survey Telescope(WFST) is a dedicated photometric surveying facility being built jointly by University of Science and Technology of China(USTC) and the Purple Mountain Observatory(PMO). It is equipped with a 2.5-meter diameter primary mirror, an active optics system, and a mosaic CCD camera with 0.73 gigapixels on the primary focal plane for highquality image capture over a 6.5-square-degree field of view. The installation of WFST near the summit of Saishiteng mountain in the Lenghu region is scheduled in summer of 2023, and the operation is planned to start three months later. WFST will scan the northern sky in four optical bands(u, g, r and i) at cadences from hourly/daily in the deep high-cadence survey(DHS) program, to semi-weekly in the wide field survey(WFS) program. During a photometric night, a nominal 30 s exposure in the WFS program will reach a depth of 22.27, 23.32, 22.84, and 22.31(AB magnitudes) in these four bands, respectively, allowing for the detection of a tremendous amount of transients in the low-z universe and a systematic investigation of the variability of Galactic and extragalactic objects. In the DHS program, intranight 90 s exposures as deep as 23(u) and 24 mag(g), in combination with target of opportunity follow-ups, will provide a unique opportunity to explore energetic transients in demand for high sensitivities, including the electromagnetic counterparts of gravitational wave events, supernovae within a few hours of their explosions,tidal disruption events and fast, luminous optical transients even beyond redshift of unity. In addition, the final 6-year co-added images, anticipated to reach g■25.8 mag in WFS or 1.5 mags deeper in DHS, will be of fundamental importance to general Galactic and extragalactic science. The highly uniform legacy surveys of WFST will serve as an indispensable complement to those of the Vera C. Rubin Observatory's Legacy Survey of Space and Time(LSST) that monitors the southern sky.
基金Supported by the National Key R&D Program of China(2018YFA0404203)the International Scholarship Program of the MOST of China(G2021166002L)+1 种基金National Natural Science Foundation of China(NSFC)(12147208,U2031103,U1931204)the Science and Technology Department of Sichuan Province(2021YFSY0031)。
文摘In the first part of this Chapter the present state of knowledge from the observations of cosmic rays between 10^(13) and 10^(20) eV is summarized.This is not intended to be a complete review,but rather a broad overview of the relevant processes involving cosmic rays,including the astrophysical environments in which they take place.This overview mainly concerns experimental results and phenomenological aspects of their interpretation,therefore experiments’description is not given but references to the vast bibliography are provided in the text.Some attempt is made to address the most popular explanations offered by theoretical models.The second part is devoted to the description of the LHAASO performance and of its capability to provide a response to several open questions,still unanswered,concerning cosmic rays above 10^(13) eV,highlighting which major steps forward in this field could be taken from LHAASO observations.
