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Wave effect of gravitational waves intersected with a microlens field II:An adaptive hierarchical tree algorithm and population study

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science China(Physics,Mechanics & astronomy) 2025年第1期68卷 237-250页

作者： Xikai Shan Guoliang Li Xuechun Chen Wen Zhao Bin Hu Shude Mao Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China department of astronomy Tsinghua UniversityBeijing 100084China Institute for Frontier in astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China School of Physics and astronomy Beijing Normal UniversityBeijing 100875China School of astronomy and space science University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaChinese Academy of SciencesHefei 230026China

The gravitational lensing wave effect generated by a microlensing field embedded in a lens galaxy is an inevitable phenomenon in strong lensed gravitational waves(SLGWs).This effect presents both challenges and opportunities for the detection and appli-cation of ***,investigating this wave effect requires computing a complete diffraction integral over each microlens in the *** is extremely time-consuming due to the large number of microlenses(10^(3)-10^(6)).Therefore,simply adding all the microlenses is ***,the complexity of the time delay surface makes the lens plane resolution a crucial factor in controlling numerical *** this paper,we propose a trapezoid approximation-based adaptive hierarchical tree algo-rithm to meet the challenges of calculation speed and *** find that this algorithm accelerates the calculation by four orders of magnitude compared to the simple adding method and is one order of magnitude faster than the fixed hierarchical tree algorithm proposed for electromagnetic *** importantly,our algorithm ensures controllable numerical errors,increasing confidence in the *** with our previous work(***.66,239511,2023),this paper addresses all numerical issues,including integral convergence,precision,and computational time1).Finally,we conducted a population study on the microlensing wave effect of SLGWs using this algorithm and found that the microlensing wave effect cannot be ignored,especially for Type II SLGWs(from saddle position of the time delay surface)due to their intrinsic geometric structures and their typical intersection with a denser microlensing ***,more than 33%(11%)of SLGWs have a mismatch larger than 1%(3%)compared to the unlensed ***,we found that the mismatch between signal pairs in a doubly imaged GW is generally larger than 10^(−3),and 61%(25%)of signal pairs have a mismatch larger than 1%(3%).Theref

关键词： gravitational lensing diffractional integral algorithm gravitational wave

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Development of Gravity Theories in the View of TRAPPIST-1e

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Research in astronomy and Astrophysics 2025年第1期25卷 143-161页

作者： Nan Wang Lu-Yao Lu Hui-Gen Liu An-Dong Chen Tiger Lu Ao-Ran Cui Jun-Kai Wang Marine science and Technology College Zhejiang Ocean University Key Laboratory of Modern astronomy and Astrophysics Ministry of Education Zhoushan Astronomical Society School of astronomy and space science Nanjing University department of astronomy Yale University Kuang Yaming Honors School Nanjing University School of Physics Nanjing University

Contrary to the solar system, most exoplanet systems detected hitherto are close-in and compact. One typical system is TRAPPIST-1, which has seven nearly co-planar terrestrial planets all within the orbit of Mercury,including three in the habitable zone. To evaluate the differences in developing sophisticated gravity theories from the solar system, we use N-body integrations to simulate ephemeris and reproduce some important astronomy phenomena observed on the potentially habitable planet TRAPPIST-1e. Retrograde motions of other planets last1–2 orders of magnitude shorter than in the solar system, but occur much more frequently. Transit events of all inner planets can be observed steadily. Except for Kepler's first law, which is hard to notice for low eccentricities of planets, the other two laws can then be precisely verified in 102days, because the areas swept by planets vary by?0.01% and the observed semimajor axes and periods result in constants with theoretical and observation accuracies both ?2%. However, the mean motion correlation implies that the Great Inequality is not always apparent between one pair of planets like Jupiter and Saturn. Furthermore, general relativity can hardly be discovered because it gives rise to perihelion precession of inner planets only ～0.1% of gravity precession, dozens of times smaller than Mercury. Our results support the possibility of developing part of gravity theories by potential exo-civilizations in compact systems like TRAPPIST-1.

关键词： ephemerides extraterrestrial intelligence gravitation planets and satellites: terrestrial planets

Analysis of Nuclear Structure Properties and Stellar β-decay Rates of Even–Even 106–120Zr Isotopes

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Research in astronomy and Astrophysics 2025年第1期25卷 162-174页

作者： Abdul Kabir Jameel-Un Nabi Syeda Anmol Rida Izzah Anwaar Noor-Ul Ain Raza Hamad Almujibah department of space science Institute of Space Technology University of Wah department of Civil Engineering College of EngineeringTaif University

The nuclear ground state properties of even–even106–120Zr nuclei have been investigated within the framework of the relativistic mean field （RMF） *** RMF model with density-dependent DDME2 and DDPC1interactions is utilized for the calculation of potential energy curves,the nuclear ground-state deformation parameters （β2）,neutron separation energies (S_nand S2n) and neutron skin thickness (rnp) of selected Zr ***,the β-decay properties of Zr isotopes were studied using the proton-neutron quasi-particle random phase approximation （pn-QRPA） *** include Gamow–Teller strength distributions,β-decay half-lives and stellar electron emission/positron capture *** β2values computed from the RMF model were employed in the pn-QRPA model as an input parameter for the calculations of β-decay properties for even–even106–120Zr *** stellar rates were computed using the pn-QRPA framework with three different types of deformation *** at high temperature （T9≥2） and low density (ρYe≤10～7g cm-3) values,the sum of electron emission and positron capture rates has a sizeable contribution （with positive exponents） to the stellar rates.

关键词： (stars:) supernovae: individual (r-process) abundances astroparticle physics elementary particles nuclear reactions nucleosynthesis

space-based optical lattice clocks as gravitational wave detectors in search for new physics

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science China(Physics,Mechanics & astronomy) 2025年第04期Mechanics & Astronomy) .卷 248-256页

作者： Bo Wang Bichu Li Qianqian Xiao Geyu Mo Yi-Fu Cai department of astronomy School of Physical SciencesUniversity of Science and Technology of China CAS Key Laboratory for Research in Galaxies and Cosmology School of Astronomy and Space ScienceUniversity of Science and Technology of China Deep space Exploration Laboratory

We investigate the sensitivity and performance of space-based optical lattice clocks（OLCs） in detecting gravitational waves,in particular the stochastic gravitational wave background（SGWB） at low frequencies(10-4, 1) Hz, which are inaccessible to ground-based detectors. We first analyze the response characteristics of a single OLC detector for SGWB detection and compare its sensitivity with that of laser interferometer space antenna（LISA）. Due to longer arm lengths, space-based OLC detectors can exhibit unique frequency responses and enhance the capability to detect SGWB in the low-frequency range, but the sensitivity of a single OLC detector remains insufficient overall compared with LISA. Then, as a preliminary plan, we adopt a method of crosscorrelation on two OLC detectors to improve the signal-to-noise ratio（SNR）. This method leverages the uncorrelated origins but statistically similar properties of noise in two detectors while the SGWB signal is correlated between them, thus achieving effective noise suppression and sensitivity enhancement. Future advancements in OLC stability are expected to further enhance their detection performance. This work highlights the potential of OLC detectors as a promising platform for SGWB detection,offering complementary capabilities to LISA, and opening an observational window into more astrophysical sources and the early universe.

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Is the Gum Nebula an important interstellar scattering disk of background pulsars?

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science China(Physics,Mechanics & astronomy) 2025年第3期68卷 175-186页

作者： Rui Wang Zhen Yan Zhiqiang Shen Ke Jia Lee Yajun Wu Rongbing Zhao Zhipeng Huang Xiaowei Wang Jie Liu Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai200030China School of astronomy and space sciences University of Chinese Academy of SciencesBeijing100049China Key Laboratory of Radio astronomy and Technology Chinese Academy of SciencesBeijing100101China School of Physical science and Technology ShanghaiTech UniversityShanghai201210China department of astronomy School of PhysicsPeking UniversityBeijing100871China Kavli Institute for astronomy and Astrophysics Peking UniversityBeijing100871China department of Physics and astronomy Hubei University of EducationWuhan430205China

The Gum Nebula is a faint supernova remnant extending about 40°across the southern sky,potentially affecting tens of background *** the view that the Gum Nebula acts as a potential scattering screen for background pulsars has been recurrently mentioned over the past five decades,it has not been directly *** chose the strong background pulsar PSR B0740-28 as a probe and monitored its diffractive interstellar scintillation(DISS)at 2.25&8.60 GHz simultaneously for about two years using the Shanghai Tian Ma Radio Telescope(TMRT).DISS was detected at both frequencies and quantified by two-dimensional autocorrelation *** calculated their scattering spectral indexαand found that 9/21 of the observations followed the theoretical predictions,while 4/21 of them clearly showedα<*** finding provides strong support for anomalous scattering along the pulsar line of sight,due to the large frequency lever arm and the simultaneous features of our dual-frequency *** comparison to the 2.25 GHz observations,scintillation arcs were observed in 10/21 of the secondary spectrum plots for 8.60 GHz ***,the highest frequency record for pulsar scintillation arc detection was updated to 8.60 *** fitting results were the most direct evidence for the view that the Gum Nebula acts as the scattering screen for background pulsars,because both the distance(245_(-72)^(+69)pc)and transverse speed(22.4_(-4.2)^(+4.1)km s^(-1))of the scintillation screen are comparable with related parameters of the Gum *** findings indicated that anisotropic scattering provides a superior explanation for the annual modulation of scintillation arcs than isotropic ***,the orientation of its long axis was also fitted.

关键词： pulsar interstellar scintillation Gum Nebula

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First Search for Pulsed CH Maser Emission Stimulated by a Pulsar

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Research in astronomy and Astrophysics 2025年第2期25卷 62-71页

作者： Mengting Liu Di Li J.R.Dawson Joel M.Weisberg George Hobbs Ningyu Tang Gan Luo Duo Xu Donghui Quan Research Center for Astronomical Computing Zhejiang Laboratory department of astronomy Tsinghua University National Astronomical Observatories Chinese Academy of Sciences CSIRO astronomy & space science Australia Telescope National Facility School of Mathematical and Physical sciences and Astrophysics and space Technologies Research Centre Macquarie University department of Physics and astronomy Carleton College department of Physics Anhui Normal University Institut de Radioastronomie Millimetrique 300 Rue de la Piscine Canadian Institute for Theoretical Astrophysics University of Toronto 60 St.George Street

We present the first search for pulsed CH maser emission potentially stimulated by PSR J1644-4559,conducted using the ultra-wide-bandwidth low-frequency receiver on Murriyang,CSIRO's Parkes Radio *** targeted three CHΛ-doublet transitions at 3264,3335,and 3349 MHz,with a variability timescale of78 *** detected ten CH emission features at 3335 and 3349 MHz,and seven features at 3264 MHz,during both pulsar-ON and pulsar-OFF *** observed velocities align with the OH emission and absorption reported by a previous study,suggesting a close spatial association between CH and OH *** derived column densities for CH clouds within the Parkes beam range from 0.05 to 9.8×1013cm-2,indicating that these clouds are likely in diffuse and translucent *** limits for CH column densities within the pulsar beam ranged from 0.3 to 9.8×*** of these column densities suggests that CH clouds may exhibit clumpiness and *** significant stimulated emission feature was detected in the optical depth ***,as part of our search for pulsed stimulated emission,we investigated the potential CH absorption of the pulsar signal and found none,in agreement with astrophysical *** upper limits for the potential maser amplification factors towards PSR J1644-4559 at 3264,3335,and 3349 MHz are 1.014,1.009,and 1.009,*** study demonstrates the feasibility of detecting pulsed CH maser emission in the interstellar medium stimulated by pulsar photons.

关键词： (stars:) pulsars: general ISM: molecules masers

Holographic thermodynamics of a charged AdS black hole with a global monopole

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Communications in Theoretical Physics 2025年第2期77卷 148-160页

作者： Hebin Zheng Yunxian Chen Jian Tang School of Physics and astronomy China West Normal University department of Physics and Electronic science Aba Teachers College

By regarding the Newton constant GNand cosmological constant Λ as variables, in this paper we study the thermodynamics and phase transition of the Reissner-Nordstr o m anti-de Sitter(RN-Ad S) black hole with a global monopole within the framework of Ad S/CFT correspondence. We find interesting critical phenomena and phase behavior in the(grand)canonical ensembles of fixed( Q,V,C),( Φ,V,C) and( Q,V,μ). When the other parameters are fixed, the free energy decreases with the global monopole increases. In the( Q,V,C) ensemble,the range of the unstable region decreases with the increase of the global monopole. In the( Φ,V,C) ensemble, when Φ < Φc, the free energy appears as two branches, where the upper and lower branches correspond to low and high entropy, respectively. When( Q,V,μ) is fixed, a new zero-order phase transition occurs in the high-entropy phase and the low-entropy phase at certainμ-dependent temperatures. When μ increases to a certain value, this zero-order phase transition disappears. This certain value is negatively related to the magnitude of the global ***, we find that p-V criticality does not appear with the change of global ***, it is important to note that the CFT states of charged black holes with global monopoles do not correspond to van der Waals fluids. Finally, we find that charged black holes with global monopoles can better reflect thermodynamic phase transitions and critical phenomena under the Ad S/CFT correspondence. By adjusting the change of the global monopole, the thermodynamic phase transition will also change.

关键词： black holes AdS-CFT correspondence global monopole

Sympathetic Solar Eruption on 2024 February 9

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Research in astronomy and Astrophysics 2025年第1期25卷 184-193页

作者： Shu-Yue Li Qing-Min Zhang Bei-Li Ying Li Feng Ying-Na Su Mu-Sheng Lin Yan-Jie Zhang School of science Nanjing University of Posts and Telecommunications Key Laboratory of Dark Matter and space astronomy Purple Mountain Observatory School of astronomy and space science University of Science and Technology of China

In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on2024 February *** primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal mass ejection （CME）,and an extreme-ultraviolet （EUV） *** between the wave and a quiescent prominence（QP） leads to a large-amplitude,transverse oscillation of *** the transverse oscillation,QP loses equilibrium and rises *** ascending motion of the prominence is coherently detected and tracked up to～1.68 R⊙by the Solar Ultra Violet Imager onboard the GOES-16 spacecraft and up to～2.2 R⊙by the Solar Corona Imager（SCI＿UV） of the Lyα Solar Telescope onboard the ASO-S *** velocity increases linearly from 12.3 to68.5 km s-1at 18:30 *** sympathetic eruption of QP drives the second CME with a typical three-part *** bright core comes from the eruptive prominence,which could be further observed up to～3.3 R⊙by the Large Angle Spectroscopic Coronagraph onboard the Solar and Heliospheric Observatory *** leading edge of the second CME accelerates continuously from～120 to～277 km *** EUV wave plays an important role in linking the primary eruption with the sympathetic eruption.

关键词： Sun: coronal mass ejections (CMEs) Sun: filaments, prominences Sun: flares

Einstein Probe discovery of EP240408a:A peculiar X-ray transient with an intermediate timescale

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science China(Physics,Mechanics & astronomy) 2025年第1期68卷 218-236页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of astronomy and space sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Institute of space sciences(ICE) CSICBarcelona E-08193Spain Institut d’Estudis Espacials de Catalunya(IEEC) Barcelona E-08034Spain Max Planck Institute for Extraterrestrial Physics Garching 85748Germany Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201210China department of Physics University of Hong KongHong Kong 999077China School of Physics and astronomy University of LeicesterLeicester LE17RHUK School of Physics and astronomy Sun Yat-sen UniversityZhuhai 519082China department of Physics Anhui Normal UniversityWuhu 241002China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China Physics department Tsinghua UniversityBeijing 100084China Nevada Center for Astrophysics University of Nevada Las VegasLas Vegas NV 89154USA department of Physics and astronomy University of Nevada Las VegasLas Vegas NV 89154USA South African Astronomical Observatory Cape Town 7935South Africa department of astronomy University of Cape TownRondebosch 7701South Africa department of Physics University of the Free StateBloemfontein 9300South Africa Universit´e Paris Cit´e CNRSAstroparticule et CosmologieParis F-75013France Universit´e Paris Cit´e CEA Paris-SaclayIRFU/DAp-AIMGif-sur-Yvette 91191France department of astronomy Guangzhou UniversityGuangzhou 510006China Cosmic Dawn Center(DAWN) Copenhagen 2200Denmark Niels Bohr Institute University of CopenhagenCopenhagen 2200Denmark department of Physics and astronomy Rutgersthe State University of New JerseyPiscataway NJ 08854-8019USA Institute for Cosmic Ray Research The University of TokyoKashiwa City 277-8582Japan ESA/ESTEC Noordwijk 2201 AZThe Netherlands department of Astronom

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe(EP)and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope(WXT)on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for 12 *** flare reached a peak flux of 3:9×10^(−9) erg cm^(−2) s^(−1) in 0.5-4 keV,∼300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying within *** X-ray light curve shows a plateau lasting for∼4 d,followed by a steep decay till becoming undetectable∼10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of∼10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients Einstein Probe

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