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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

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

New discoveries of young stars revise our star formation history in the Taurus Molecular Cloud

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Science China(Physics,Mechanics & astronomy) 2025年第04期Mechanics & Astronomy) .卷 267-268页

作者： Gregory J.Herczeg Kavli Institute for astronomy and astrophysics Peking University Department of astronomy School of Physics Peking University

As one of the nearest sites of low-mass star formation, the Taurus Molecular Cloud provides us with a foundation for how low-mass stars form and evolve. The members include T Tau, the namesake for the entire T Tauri class of stars, the famous HL Tau disk, and several of the most famous protostars. The cluster is not a single site of star formation, but a complicated combination of very young protostars, older generations of stars, along with gas and dust.

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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

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

New Insights on Gamma-Ray Burst Radiation Mechanisms from Multiwavelength Observations

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Research in astronomy and astrophysics 2025年第2期25卷 3-12页

作者： Yu-Hua Yao Fang-Sheng Min Shi Chen Yi-Qing Guo College of Physics Chongqing University Key Laboratory of Particle astrophysics Institute of High Energy Physics Chinese Academy of Sciences Wisconsin Ice Cube Particle astrophysics Center University of Wisconsin–Madison university of Chinese Academy of Sciences School of Physics and astronomy Yunnan University Tianfu Cosmic Ray Research Center

The study of high-energy gamma-ray emission from gamma-ray bursts(GRBs) involves complex synchrotron radiation and synchrotron self-Compton(SSC) scattering mechanisms with multiple parameters exhibiting a wide distribution. Recent advancements in GRB research, particularly the observation of very high energy(VHE,>100 Ge V) radiation, have ushered in a new era of multiwavelength exploration, offering fresh perspectives and limitations for understanding GRB radiation mechanisms. This study aimed to leverage VHE observations to refine constraints on synchrotron + SSC radiation from electrons accelerated by forward shocks. By analyzing two external environments—the uniform interstellar medium and stratified stellar wind medium, we conducted spectral and variability fitting for five specific bursts(GRB 180720B, GRB 190114C, GRB 190829A, GRB 201216C, and GRB 221009A) to identify the optimal parameters characterizing these events. A comparative analysis of model parameter distributions with and without VHE radiation observations reveals that the magnetic energy equipartition factor εBis more concentrated with VHE emissions. This suggests that VHE emissions may offer greater constraints on this microphysical parameter. Additionally, we found that the energy budget between VHE and ke V–Me V γ-ray emissions under the SSC radiation exhibits an almost linear relationship, which may serve as a tool to differentiate radiation mechanisms. We anticipate future statistical analyses of additional VHE bursts to validate our findings.

关键词： (transients:) gamma-ray bursts gamma-rays: ISM radiation mechanisms: non-thermal

Sky location of massive black hole binaries in the foreground of Galactic white dwarf binaries

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Science China(Physics,Mechanics & astronomy) 2025年第1期68卷 93-104页

作者： Pan Guo Hong-Bo Jin Cong-Feng Qiao Yue-Liang Wu The international centre for Theoretical Physics Asia-Pacific University of Chinese Academy of SciencesBeijing 100190China Institute for Frontiers in astronomy and astrophysics Beijing Normal UniversityBeijing 102206China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China The School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China

For space-based gravitational wave(GW)detection,the main noise source for massive black hole binaries(MBHBs)is attributed to approximately 107 double white dwarf binaries in the *** a GW source,the amplitude of the detector response,recorded by a space-based gravitational wave detector,exhibits a modulation effect with a year period when observing the source from various orbital *** the adverse conditions mentioned above,where there is a strong foreground noise and annual modulation in the signals,we employed the wavelet transform and the strong-amplitude relevant orbital position search methods,which allows the weak MBHB sources to achieve higher locating *** detail,for two MBHB sources of lower intensity,the precision of luminosity distance,represented by the ratioΔD_(L)/D_(L) at the 95%confidence level,is enhanced by factors of∼*** angular resolutions,denoted byΔΩs,are enhanced by a factor of∼*** improvements increase the number of detectable GW sources,facilitate multi-messenger follow-up observations and provide constraints on the cosmological constant.

关键词： space-based gravitational wave detection gravitational waves massive black hole binaries

A Multi-faceted View of the X-Ray Spectral Variability in Seyfert Galaxy Ark 120

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Research in astronomy and astrophysics 2025年第1期25卷 228-239页

作者： Lu-Xin Ren Jun-Xian Wang Jia-Lai Kang CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of China School of astronomy and Space Science University of Science and Technology of China

Utilizing a range of techniques including multi-band light curves,softness ratio analysis,structure functions,rms spectra,cross-correlation functions,and ratios of spectra from different intervals,we present a comprehensive study of the complex X-ray spectral variability in Seyfert 1 galaxy Ark 120,through re-analyzing its six XMM-Newton observations taken between 2003 and *** find a clear“softer-when-brighter”trend in the 2–10 ke V power-law component over long timescales,with this trend being timescale dependent,as it is much weaker on shorter timescales,similar to that previously detected in NGC ***,a rare“harder-when-brighter”trend is observed during one exposure,indicating dynamic changes in the spectral variability behavior of the power-law *** exceptional exposure,with the spectral variability indeed marked by a power-law pivoting at an unusually low energy of～2 ke V,suggests intricate variations in the thermal Comptonization processes within the ***,when the data below 2 ke V are included,we identify that the soft excess component adds significant complexity to the spectral variability,such as evidenced by a transition from“harder-when-brighter”to“softer-when-brighter”during another single *** extra complexity arises because the variability of the soft excess sometimes follows and sometimes does not follow the changes in the power-law *** findings underscore the necessity of applying multiple analytic techniques to fully capture the multifaceted spectral variability of AGNs.

关键词： galaxies: active galaxies: Seyfert X-rays: galaxies

Science objectives of the Einstein Probe mission

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Science China(Physics,Mechanics & astronomy) 2025年第3期68卷 1-60页

作者： Weimin Yuan Lixin Dai Hua Feng Chichuan Jin Peter Jonker Erik Kuulkers Yuan Liu Kirpal Nandra Paul O’Brien Luigi Piro Arne Rau Nanda Rea Jeremy Sanders Lian Tao Junfeng Wang Xuefeng Wu Bing Zhang Shuangnan Zhang Shunke Ai Johannes Buchner Esra Bulbul Hechao Chen Minghua Chen Yong Chen Yu-Peng Chen Alexis Coleiro Francesco Coti Zelati Zigao Dai Xilong Fan Zhou Fan Susanne Friedrich He Gao Chong Ge Mingyu Ge Jinjun Geng Giancarlo Ghirlanda Giulia Gianfagna Lijun Gou Sebastien Guillot´ Xian Hou Jingwei Hu Yongfeng Huang Long Ji Shumei Jia S.Komossa Albert K.H.Kong Lin Lan An Li Ang Li Chengkui Li Dongyue Li Jian Li Zhaosheng Li Zhixing Ling Ang Liu Jinzhong Liu Liangduan Liu Zhu Liu Jiawei Luo Ruican Ma Pierre Maggi Chandreyee Maitra Alessio Marino Stephen Chi-Yung Ng Haiwu Pan Surangkhana Rukdee Roberto Soria Hui Sun Pak-Hin Thomas Tam Aishwarya Linesh Thakur Hui Tian Eleonora Troja Wei Wang Xiangyu Wang Yanan Wang Junjie Wei Sixiang Wen Jianfeng Wu Ting Wu Di Xiao Dong Xu Renxin Xu Yanjun Xu Yu Xu Haonan Yang Bei You Heng Yu Yunwei Yu Binbin Zhang Chen Zhang Guobao Zhang Liang Zhang Wenda Zhang Yu Zhang Ping Zhou Zecheng Zou National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Physics University of Hong KongPokfulam RoadHong Kong 999077China Key Laboratory of Particle astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Department of astrophysics/IMAPP Radboud UniversityNijmegen6500 GLthe Netherlands SRON Netherlands Institute for Space ResearchLeiden2333 CAthe Netherlands ESA/ESTEC Noordwijk2201 AZthe Netherlands Max Planck Institute for Extraterrestrial Physics Garching85748Germany School of Physics and astronomy University of LeicesterLeicesterLE17RHUK INAF-Istituto di Astrofisica e Planetologia Spaziali Rome00133Italy Institute of Space Sciences(ICE) CSICCampus UABBarcelonaE-08193Spain Institut d’Estudis Espacials de Catalunya(IEEC) BarcelonaE-08034Spain Department of astronomy Xiamen UniversityXiamen 361005China Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China Nevada Center for astrophysics University of NevadaLas VegasNV 89154USA Department of Physics and astronomy University of NevadaLas VegasNV 89154USA Department of astronomy School of Physics and TechnologyWuhan UniversityWuhan 430072China School of Physics and astronomy Yunnan UniversityKunming 650500China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Universit´e Paris Cit´e CNRSAstroparticule et CosmologieParisF-75013France Department of astronomy University of Science and Technology of ChinaHefei 230026China Institute for Frontier in astronomy and astrophysics Beijing Normal UniversityBeijing 102206China Department of astronomy Beijing Normal UniversityBeijing 100875China INAF-Osservatorio Astronomico di Brera Merate(LC)I-23807Italy INFN-sezione di Milano-Bicocca Milano(M

The Einstein Probe(EP)is an interdisciplinary mission of time-domain and X-ray *** with a wide-field lobstereye X-ray focusing imager,EP will discover cosmic X-ray transients and monitor the X-ray variability of known sources in 0.5-4 keV,at a combination of detecting sensitivity and cadence that is not accessible to the previous and current wide-field monitoring *** can perform quick characterisation of transients or outbursts with a Wolter-I X-ray telescope *** this paper,the science objectives of the EP mission are *** is expected to enlarge the sample of previously known or predicted but rare types of transients with a wide range of *** them,fast extragalactic transients will be surveyed systematically in soft X-rays,which includeγ-ray bursts and their variants,supernova shock breakouts,and the predicted X-ray transients associated with binary neutron star *** will detect X-ray tidal disruption events and outbursts from active galactic nuclei,possibly at an early phase of the flares for *** will monitor the variability and outbursts of X-rays from white dwarfs,neutron stars and black holes in our and neighbouring galaxies at flux levels fainter than those detectable by the current instruments,and is expected to discover new objects.A large sample of stellar X-ray flares will also be detected and *** the era of multi-messenger astronomy,EP has the potential of detecting the possible X-ray counterparts of gravitational wave events,neutrino sources,and ultra-high energyγ-ray and cosmic ray *** is expected to help advance the studies of extreme objects and phenomena revealed in the dynamic X-ray universe,and their underlying physical *** EP's strength in time-domain science,its follow-up telescope,with excellent performance,will also enable advances in many areas of X-ray astronomy.

关键词： Einstein Probe X-ray astronomy X-ray telescopes time-domain astronomy transients variability