期刊文献+
共找到2,097篇文章
< 1 2 105 >
每页显示 20 50 100
The prospects of using gravitational waves for constraining the anisotropy of the Universe
1
作者 赵志超 林海南 常哲 《中国物理C:英文版》 SCIE CAS CSCD 2019年第7期112-117,共6页
The observation of GW150914 gave a new independent measurement of the luminosity distance of a gravitational wave event. In this paper, we constrain the anisotropy of the Universe by using gravitational wave events.We... The observation of GW150914 gave a new independent measurement of the luminosity distance of a gravitational wave event. In this paper, we constrain the anisotropy of the Universe by using gravitational wave events.We simulate hundreds of events of binary neutron star merger that may be observed by the Einstein Telescope. Full simulation of the production process of gravitational wave data is employed. We find that 200 binary neutron star merging events with the redshift in (0,1) observed by the Einstein Telescope may constrain the anisotropy with an accuracy comparable to that from the Union2.1 supernovae. This result shows that gravitational waves can be a powerful tool for investigating cosmological anisotropy. 展开更多
关键词 GRAVITATIONAL WAVE ANISOTROPIC SPACE-TIME GRAVITATIONAL WAVE detector
Applying deep neural networks to the detection and space parameter estimation of compact binary coalescence with a network of gravitational wave detectors
2
作者 XiLong Fan Jin Li +2 位作者 Xin Li YuanHong Zhong JunWei Cao 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第6期122-129,共8页
In this paper, we study an application of deep learning to the advanced laser interferometer gravitational wave observatory(LIGO)and advanced Virgo coincident detection of gravitational waves(GWs) from compact binary ... In this paper, we study an application of deep learning to the advanced laser interferometer gravitational wave observatory(LIGO)and advanced Virgo coincident detection of gravitational waves(GWs) from compact binary star mergers. This deep learning method is an extension of the Deep Filtering method used by George and Huerta(2017) for multi-inputs of network detectors.Simulated coincident time series data sets in advanced LIGO and advanced Virgo detectors are analyzed for estimating source luminosity distance and sky location. As a classifier, our deep neural network(DNN) can effectively recognize the presence of GW signals when the optimal signal-to-noise ratio(SNR) of network detectors ≥ 9. As a predictor, it can also effectively estimate the corresponding source space parameters, including the luminosity distance D, right ascension α, and declination δ of the compact binary star mergers. When the SNR of the network detectors is greater than 8, their relative errors are all less than 23%.Our results demonstrate that Deep Filtering can process coincident GW time series inputs and perform effective classification and multiple space parameter estimation. Furthermore, we compare the results obtained from one, two, and three network detectors;these results reveal that a larger number of network detectors results in a better source location. 展开更多
关键词 deep neural networks ADVANCED LIGO and ADVANCED Virgo coincident DETECTION of GRAVITATIONAL waves multiple SPACE parameter estimation
Aerosol transportation in horizontal channels w让h gravitational effects
3
作者 Yongwei Gao Ke Zhong Yanming Kang 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第3期159-168,共10页
Aerosol particle deposition in a narrow horizontal channel with gravitational effects is studied in the laminar flow regime. A general explic让 solution for predicting the aerosol transportation in the channel is obta... Aerosol particle deposition in a narrow horizontal channel with gravitational effects is studied in the laminar flow regime. A general explic让 solution for predicting the aerosol transportation in the channel is obtained theoretically. The characteristics of the asymmetric concentratio n profiles and their dependence on gravitational settling are analyzed for different settings of the diffusion and sedimentation parameters. Aerosol deposition on the channel walls, which is influenced by a combination of mechanisms, is also analyzed. The results are compared with those from simplified models obtained in previous studies in which only diffusion or gravity was considered. The analysis reveals that the literature results regarding this aspect may be simplified with the present solution under specific conditions. 展开更多
关键词 EXACT solution Combined DEPOSITION GRAVITATIONAL effect HORIZONTAL channel ASYMMETRIC distribution
Constraining the non-Einsteinian polarizations of gravitational waves by pulsar timing array
4
作者 Rui Niu Wen Zhao 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第7期63-75,共13页
Pulsar timing array(PTA) provides an excellent opportunity to detect the gravitational waves(GWs) in nanoHertz frequency band.In particular, due to the larger number of 'arms' in PTA, it can be used to test gr... Pulsar timing array(PTA) provides an excellent opportunity to detect the gravitational waves(GWs) in nanoHertz frequency band.In particular, due to the larger number of 'arms' in PTA, it can be used to test gravity by probing the non-Einsteinian polarization modes of GWs, including two spin-1 shear modes labeled by 'sn' and 'se', the spin-0 transverse mode labeled by 'b' and the longitudinal mode labeled by 'l'. In this paper, we investigate the capabilities of the current and potential future PTAs, which are quantified by the constraints on the amplitudes parameters(cb, csn, cse, cl), by observing an individual supermassive black hole binary in Virgo cluster. We find that for binary with total mass Mc= 8.77 × 108 M⊙ and GW frequency f = 10-9 Hz, the PTA at current level can detect these GW modes if cb> 0.00106, cl> 0.00217, cse> 0.00271, csn> 0.00141, which will be improved by about two orders if considering the potential PTA in SKA era. Interesting enough, due to effects of the geometrical factors, we find that in SKA era, the constraints on the l, sn, se modes of GWs are purely dominated by several pulsars, instead of the full pulsars in PTA. 展开更多
关键词 GRAVITATIONAL WAVES pulsar TIMING ARRAY
The Noncommutative Residue about Witten Deformation
5
作者 Kai Hua BAO Ai Hui SUN Chao DENG 《数学学报:英文版》 SCIE CSCD 2019年第4期550-568,共19页
In this paper, we compute lower dimensional volumes Vol4(1,1) and Vol6(2,2) about Witten deformation for 4, 6-dimensional spin manifolds with boundary respectively, and get assosiated Kastler–Kalau–Walze type theore... In this paper, we compute lower dimensional volumes Vol4(1,1) and Vol6(2,2) about Witten deformation for 4, 6-dimensional spin manifolds with boundary respectively, and get assosiated Kastler–Kalau–Walze type theorems. We also give theoritic explaination of the gravitational action for 4, 6 dimensional manifolds with boundary by these noncommutative residues. 展开更多
关键词 Lower-dimensional VOLUMES NONCOMMUTATIVE RESIDUE GRAVITATIONAL action WITTEN DEFORMATION
Geochemistry and petrology of superpure quartzites from East Sayan Mountains,Russia
6
作者 A.M.Fedorov V.A.Makrygina +4 位作者 A.I.Nepomnyaschikh A.P.Zhaboedov A.V.Parshin V.F.Posokhova Yu.V.Sokolnikova 《中国地球化学学报:英文版》 EI CAS CSCD 2019年第1期22-39,共18页
Quartzites are widespread within Earth's lithosphere,but their highly pure varieties occur quite infrequently.With the development of alternative energy sources,including solar,and with increasing demand for high-... Quartzites are widespread within Earth's lithosphere,but their highly pure varieties occur quite infrequently.With the development of alternative energy sources,including solar,and with increasing demand for high-purity quartz for optics,interest has risen in high-urity silicon-bearing materials.The quartzites discovered in the southeast part of the Eastern Sayan Mountains are particularly attractive for exploration in terms of their raw material quality and feasibility to be enriched.For this reason,their genesis also merits study.Available geochemical data show that chemogenic (d18O >29.2%o) siliceous-carbonate sediments of the Irkut Formation are fairly pure (impurity elements <800 ppm),and that half the impurities are easily removed carbonate components of the rock.Bedded quartzites remote from the intrusive granitoids and near-contact quartzites were recognized based on geochemical and petrographic data.Influenced by the Sumsunur granitoids,the near-contact quartzites originally contained >0.9%impurities,but later,under the action of sliding slabs of ophiolite dynamothermal treatment reduced impurities to <100 ppm,resulting in "superquartzites"(highly pure quartzites).The presence of only minor structural impurities is due to the enrichment capacity of superquartzites to 10.1 ppm (7.2 ppm under special conditions)of 10 elements:Fe,AI,Ti,Ca,Mg,Cu,Mn,Na,K,and Li. 展开更多
关键词 HIGH-PURITY quartz Superquartzite GRAVITATIONAL SLIDING Dynamic METAMORPHISM RECRYSTALLIZATION
Time-crystal ground state and production of gravitational waves from QCD phase transition
7
作者 Andrea Addazi Antonino Marcianò Roman Pasechnik 《中国物理C:英文版》 SCIE CAS CSCD 2019年第6期115-125,共11页
We propose a novel mechanism for the production of gravitational waves in the early Universe that originates from the relaxation processes induced by the QCD phase transition. While the energy density of the quark-glu... We propose a novel mechanism for the production of gravitational waves in the early Universe that originates from the relaxation processes induced by the QCD phase transition. While the energy density of the quark-gluon mean-field is monotonously decaying in real time, its pressure undergoes a series of violent oscillations at the characteristic QCD time scales that generate a primordial multi-peaked gravitational waves signal in the radio frequencies’ domain. The signal is an echo of the QCD phase transition that is accessible by planned measurements at the FAST and SKA telescopes. 展开更多
关键词 primordial GRAVITATIONAL waves HOMOGENEOUS GLUON CONDENSATE effective YANG-MILLS theory QCD phase tran sition
An Approximation of the Steady Gravity Wave Induced by Mountainous Topography
8
作者 许鹏程 左群杰 高守亭 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第2期253-258,共6页
An approximation of the orography gravity wave, which is induced by mountainous topography, is considered in this study. By assuming that the horizontal wind is a linear function with respect to the height, the approx... An approximation of the orography gravity wave, which is induced by mountainous topography, is considered in this study. By assuming that the horizontal wind is a linear function with respect to the height, the approximating equation for the orography gravity waves is obtained. Four topography functions are considered in this study and the orography gravity wave are obtained. The dynamics of the orography gravity wave is then discussed by considering the effect of the surface topography and background horizontal wind. 展开更多
关键词 GRAVITATIONAL WAVES extreme-mass-ratio-inspirals supermassive black hole
Observatory science with eXTP
9
作者 Jean J. M. in 't Zand Enrico Bozzo +103 位作者 JinLu Qu Xiang-Dong Li Lorenzo Amati Yang Chen Immacolata Donnarumma Victor Doroshenko Stephen A. Drake Margarita Hernanz Peter A. Jenke Thomas J. Maccarone Simin Mahmoodifar Domitilla de Martino Alessandra De Rosa Elena M. Rossi Antonia Rowlinson Gloria Sala Giulia Stratta Thomas M. Tauris Joern Wilms XueFeng Wu Ping Zhou Iván Agudo Diego Altamirano Jean-Luc Atteia Nils A. Andersson M. Cristina Baglio David R. Ballantyne Altan Baykal Ehud Behar Tomaso Belloni Sudip Bhattacharyya Stefano Bianchi Anna Bilous Pere Blay Jo ao Braga S?ren Brandt Edward F. Brown Niccolò Bucciantini Luciano Burderi Edward M. Cackett Riccardo Campana Sergio Campana Piergiorgio Casella Yuri Cavecchi Frank Chambers Liang Chen Yu-Peng Chen Jérome Chenevez Maria Chernyakova ChiChuan Jin Riccardo Ciolfi Elisa Costantini Andrew Cumming Antonino D'Aì Zi-Gao Dai Filippo D'Ammando Massimiliano De Pasquale Nathalie Degenaar Melania Del Santo Valerio D'Elia Tiziana Di Salvo Gerry Doyle Maurizio Falanga XiLong Fan Robert D. Ferdman Marco Feroci Federico Fraschetti Duncan K. Galloway Angelo F. Gambino Poshak Gandhi MingYu Ge Bruce Gendre Ramandeep Gill Diego Gotz Christian Gouiffès Paola Grandi Jonathan Granot Manuel Güdel Alexander Heger Craig O. Heinke Jeroen Homan Rosario Iaria Kazushi Iwasawa Luca Izzo Long Ji Peter G. Jonker Jordi José Jelle S. Kaastra Emrah Kalemci Oleg Kargaltsev Nobuyuki Kawai Laurens Keek Stefanie Komossa Ingo Kreykenbohm Lucien Kuiper Devaky Kunneriath Gang Li En-Wei Liang Manuel Linares Francesco Longo FangJun Lu Alexander A. Lutovinov Denys Malyshev Julien Malza 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第2期97-138,共42页
In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies related toObservatory Science targets. These include flaring stars, supernova remnants, accreting wh... In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies related toObservatory Science targets. These include flaring stars, supernova remnants, accreting white dwarfs, low and high mass X-raybinaries, radio quiet and radio loud active galactic nuclei, tidal disruption events, and gamma-ray bursts. eXTP will be excellentlysuited to study one common aspect of these objects: their often transient nature. Developed by an international Consortium ledby the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in themid 2020s. 展开更多
关键词 space research instruments nuclear ASTROPHYSICS flare stars ACCRETION and ACCRETION disks mass loss and stellar winds cataclysmic BINARIES X-RAY BINARIES supernova REMNANTS active galactic nuclei X-RAY BURSTS gamma-ray BURSTS gravitational waves
Numerical simulation of time delay interferometry for TAIJI and new LISA
10
作者 Gang Wang Wei-Tou Ni 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2019年第4期95-108,共14页
The success of LISA Pathfinder in demonstrating the LISA drag-free requirement paved the way for using space interferometers to detect low-frequency and middle-frequency gravitational waves(GWs). The TAIJI GW mission ... The success of LISA Pathfinder in demonstrating the LISA drag-free requirement paved the way for using space interferometers to detect low-frequency and middle-frequency gravitational waves(GWs). The TAIJI GW mission and the new LISA GW mission propose using an arm length of 3 Gm(1 Gm = 10~6 km) and an arm length of 2.5 Gm respectively. For a space laser-interferometric GW antenna,due to astrodynamical orbit variation, time delay interferometry(TDI) is needed to achieve nearly equivalent equal-arms for suppressing the laser frequency noise below the level of optical path noise, acceleration noise, etc in order to attain the requisite sensitivity. In this paper, we simulate TDI numerically for the TAIJI mission and the new LISA mission. To do this, we work out a set of 2200-day(6-year) optimized science orbits for each mission starting on 2028 March 22 using the CGC 2.7.1 ephemeris framework. Then we use the numerical method to calculate the residual optical path differences of the first-generation TDI configurations and the selected second-generation TDI configurations. The resulting optical path differences of the second-generation TDI configurations calculated for TAIJI, new LISA and eLISA are well below their respective requirements for laser frequency noise cancelation. However, for the first-generation TDI configurations, the original requirements need to be relaxed by 3 to 30 fold to be satisfied. For TAIJI and the new LISA, about one order of magnitude relaxation would be good and recommended;this could be borne on the laser stability requirement in view of recent progress in laser stability, or the GW detection sensitivities of the second-generation TDIs have to be used in the diagnosis of the observed data instead of the commonly used X, Y and Z TDIs. 展开更多
关键词 GRAVITATIONAL waves methods:numerical techniques:interferometric
Probing primordial gravitational waves: Ali CMB Polarization Telescope
11
作者 Hong Li Si-Yu Li +14 位作者 Yang Liu Yong-Ping Li Yifu Cai Mingzhe Li Gong-Bo Zhao Cong-Zhan Liu Zheng-Wei Li He Xu Di Wu Yong-Jie Zhang Zu-Hui Fan Yong-Qiang Yao Chao-Lin Kuo Fang-Jun Lu Xinmin Zhang 《国家科学评论:英文版》 CSCD 2019年第1期145-154,共10页
In this paper, we will give a general introduction to the Ali CMB Polarization Telescope(Ali CPT) project,which is a Sino–US joint project led by the Institute of High Energy Physics and involves many different insti... In this paper, we will give a general introduction to the Ali CMB Polarization Telescope(Ali CPT) project,which is a Sino–US joint project led by the Institute of High Energy Physics and involves many different institutes in China. It is the first ground-based Cosmic Microwave Background(CMB) polarization experiment in China and an integral part of China’s Gravitational-wave Program. The main scientific goal of the Ali CPT project is to probe the primordial gravitational waves(PGWs) originating from the very early Universe. The AliCPT project includes two stages. The first stage, referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet at an altitude of 5250 meters. Once completed, it will be the highest ground-based CMB observatory in the world and will open a new window for probing PGWs in the northern hemisphere. The AliCPT-1 telescope is designed to have about 7000 transition-edge sensor detectors at 95 GHz and 150 GHz. The second stage is to have a more sensitive telescope(Ali CPT-2) with more than 20 000 detectors. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio r by one order of magnitude with three years’ observation. Besides the PGWs, Ali CPT will also enable a precise measurement of the CMB rotation angle and provide a precise test of the CPT symmetry. We show that three years’ observation will improve the current limit by two orders of magnitude. 展开更多
关键词 primordial GRAVITATIONAL waves COSMIC microwave background ALI CMB POLARIZATION TELESCOPE
The role of FAST in pulsar timing arrays
12
作者 George Hobbs Shi Dai +4 位作者 Richard N.Manchester Ryan M.Shannon Matthew Kerr Ke-Jia Lee Ren-Xin Xu 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2019年第2期39-54,共16页
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) will become one of the world-leading telescopes for pulsar timing array(PTA) research. The primary goals for PTAs are to detect(and subsequently study) u... The Five-hundred-meter Aperture Spherical radio Telescope(FAST) will become one of the world-leading telescopes for pulsar timing array(PTA) research. The primary goals for PTAs are to detect(and subsequently study) ultra-low-frequency gravitational waves, to develop a pulsar-based time standard and to improve solar system planetary ephemerides. FAST will have the sensitivity to observe known pulsars with significantly improved signal-to-noise ratios and will discover a large number of currently unknown pulsars. We describe how FAST will contribute to PTA research and show that jitter-and timing-noise will be the limiting noise processes for FAST data sets. Jitter noise will limit the timing precision achievable over data spans of a few years while timing noise will limit the precision achievable over many years. 展开更多
关键词 stars:pulsars GRAVITATIONAL WAVES
Estimation of spectrum and parameters of relic gravitational waves using space-borne interferometers
13
作者 Bo Wang Yang Zhang 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2019年第2期77-110,共34页
We present a study of spectrum estimation of relic gravitational waves(RGWs) as a Gaussian stochastic background from output signals of future space-borne interferometers, like LISA and ASTROD.As the target of detecti... We present a study of spectrum estimation of relic gravitational waves(RGWs) as a Gaussian stochastic background from output signals of future space-borne interferometers, like LISA and ASTROD.As the target of detection, the analytical spectrum of RGWs generated during inflation is described by three parameters: the tensor-scalar ratio, the spectral index and the running index. The Michelson interferometer is shown to have a better sensitivity than Sagnac and symmetrized Sagnac. For RGW detection, we analyze the auto-correlated signals for a single interferometer, and the cross-correlated, integrated as well as unintegrated signals for a pair of interferometers, and give the signal-to-noise ratio(SNR) for RGW, and obtain lower limits of the RGW parameters that can be detected. By suppressing noise level, a pair has a sensitivity2 orders better than a single for one year observation. SNR of LISA will be 4–5 orders higher than that of Advanced LIGO for the default RGW. To estimate the spectrum, we adopt the maximum likelihood(ML)estimation, calculate the mean and covariance of signals, obtain the Gaussian probability density function(PDF) and the likelihood function, and derive expressions for the Fisher matrix and the equation of the ML estimate for the spectrum. The Newton-Raphson method is used to solve the equation by iteration. When the noise is dominantly large, a single LISA is not effective for estimating the RGW spectrum as the actual noise in signals is not known accurately. For cross-correlating a pair, the spectrum cannot be estimated from the integrated output signals either, and only one parameter can be estimated with the other two being either fixed or marginalized. We use the ensemble averaging method to estimate the RGW spectrum from the un-integrated output signals. We also adopt a correlation of un-integrated signals to estimate the spectrum and three parameters of RGW in a Bayesian approach. For all three methods, we provide simulations to illustrate their feasibility. 展开更多
关键词 GRAVITATIONAL WAVES COSMOLOGICAL parameters instrumentation:detectors early UNIVERSE
Gravitational constant in f(R) theories of gravity with non-minimal coupling between matter and geometry
14
作者 王俊 曹丽佳 《中国物理快报:英文版》 SCIE CAS CSCD 2018年第12期76-79,共4页
We study the effect of the non-minimal coupling between matter and geometry on the gravitational constant in the context of f(R) theories of gravity on cosmic scales. For a class of f(R) models,the result shows that t... We study the effect of the non-minimal coupling between matter and geometry on the gravitational constant in the context of f(R) theories of gravity on cosmic scales. For a class of f(R) models,the result shows that the value of the gravitational constant not only changes over time but also has the dampened oscillation behavior.Compared with the result of the standard ACDM model, the consequence suggests that the coupling between matter and geometry should be weak. 展开更多
关键词 CDM theories of GRAVITY with non-minimal coupling BETWEEN MATTER and GEOMETRY GRAVITATIONAL constant in F
An axion-like scalar field environment effect on binary black hole merger
15
作者 Qing Yang Li-Wei Ji +2 位作者 Bin Hu Zhou-Jian Cao Rong-Gen Cai2 《天文和天体物理学研究:英文版》 CSCD 2018年第6期35-48,共14页
The environment, such as an accretion disk, could modify the signal of the gravitational wavefrom astrophysical black hole binaries. In this article, we model the matter field around intermediate-mass binary black hol... The environment, such as an accretion disk, could modify the signal of the gravitational wavefrom astrophysical black hole binaries. In this article, we model the matter field around intermediate-mass binary black holes by means of an axion-like scalar field and investigate their joint evolution. Indetail, we consider equal mass binary black holes surrounded by a shell of axion-like scalar field bothin spherically symmetric and non-spherically symmetric cases, and with different strengths of the scalarfield. Our result shows that the environmental scalar field could essentially modify the dynamics. Firstly,in the spherically symmetric case, with increase of the scalar field strength, the number of circular orbitsfor the binary black hole is reduced. This means that the scalar field could significantly accelerate themerger process. Secondly, once the scalar field strength exceeds a certain critical value, the scalar fieldcould collapse into a third black hole with its mass being larger than that of the binary. Consequently,the new black hole that collapses from the environmental scalar field could accrete the binary promptlyand the binary collides head-on with each other. In this process, there is almost no quadrupole signalproduced, and, consequently, the gravitational wave is greatly suppressed. Thirdly, when the scalar fieldstrength is relatively smaller than the critical value, the black hole orbit could develop eccentricitythrough accretion of the scalar field. Fourthly, during the initial stage of the inspiral, the gravitationalattractive force from the axion-like scalar field could induce a sudden turn in the binary orbits, henceresulting in a transient wiggle in the gravitational waveform. Finally, in the non-spherical case, the scalarfield could gravitationally attract the binary moving toward the center of mass for the scalar field andslow down the merger process. 展开更多
关键词 stars: black HOLES -- GRAVITATIONAL WAVES -- methods: numerical
GWs from S-stars Revolving Around SMBH at Sgr A
16
作者 蔡荣根 刘同波 王少江 《理论物理通讯:英文版》 SCIE CAS CSCD 2018年第12期735-748,共14页
A preliminary estimation of gravitational waves (GWs) from the extreme-mass-ratio-inspirals (EMRIs) system in the Galactic Centre (GC) is given for the 37 observed S-stars revolving around the supermassive black hole ... A preliminary estimation of gravitational waves (GWs) from the extreme-mass-ratio-inspirals (EMRIs) system in the Galactic Centre (GC) is given for the 37 observed S-stars revolving around the supermassive black hole (SMBH) at Sagittarius (Sgr) A^*.Within this century,the total strain of the gravitational waveform calculated from the post-Newtonian (PN) method with eccentricity is well below the current planned sensitivity of pulsar-timing-array (PTA).New technology might be required in order to extract GW signal from this EMRIs system for future PTA detections. 展开更多
关键词 GRAVITATIONAL WAVES extreme-mass-ratio-inspirals supermassive black hole
A magnetically driven origin for the low luminosity GRB 170817 Aassociated with GW170817
17
作者 Hao Tong Cong Yu Lei Huang 《天文和天体物理学研究:英文版》 CSCD 2018年第6期59-64,共6页
The gamma-ray burst GR170817A associated with GW170817 is subluminous and suben-ergetic compared with other typical short gamma-ray bursts. It may be due to a relativistic jet viewedoff-axis, or a structured jet or co... The gamma-ray burst GR170817A associated with GW170817 is subluminous and suben-ergetic compared with other typical short gamma-ray bursts. It may be due to a relativistic jet viewedoff-axis, or a structured jet or cocoon emission. Giant flares from magnetars may possibly be ruled out.However, the luminosity and energetics of GRB 170817A are coincident with those of magnetar giantflares. After the coalescence of a binary neutron star, a hypermassive neutron star may be formed. Thehypermassive neutron star may have a magnetar-strength magnetic field. During the collapse of thishypermassive neutron star, magnetic field energy will also be released. This giant-flare-like event mayexplain the luminosity and energetics of GRB 170817A. Bursts with similar luminosity and energeticsare expected in future neutron star-neutron star or neutron star-black hole mergers. 展开更多
关键词 stars: MAGNETAR -- stars: neutron -- GAMMA-RAY bursts: individual (GRB 170817A) --gravitational waves
Testing Photons Coupled to Weyl Tensor with Gravitational Time Advancement
18
作者 李刚 邓雪梅 《理论物理通讯:英文版》 SCIE CAS CSCD 2018年第12期721-727,共7页
Classical Solar System tests of photons coupled to Weyl tensor with two polarizations were studied in a recent work.A coupling strength parameter in this model was firstly obtained as |α| ■4×10^11m^2 by using a... Classical Solar System tests of photons coupled to Weyl tensor with two polarizations were studied in a recent work.A coupling strength parameter in this model was firstly obtained as |α| ■4×10^11m^2 by using available datasets in the Solar System.In this paper,a new test called by gravitational time advancement is proposed and investigated to test such the coupling.This new test,which is quite different from Shapiro time delay,depends strongly on round-trip proper time span (not coordinate time one) of flight of radio pulses between an observer on the Earth and a distant spacecraft.For ranging a spacecraft getting far away from the Sun,two special cases (the superior/inferior conjunctions) are used to analyse the observability in the advancement contributed by the Weyl coupling.We found that the situation of the inferior conjunction is more suitable for detecting the advancement caused by such the Weyl coupling.In either case,two kinds of polarizations make the advancement in the model smaller or larger than the one of general relativity.Although the observability in the advancement could be out of the reach of already existing technology,the implement of planetary laser ranging and optical clocks might provide us more insights on such the Weyl coupling in the near future. 展开更多
关键词 GRAVITATION EXPERIMENTAL tests of GRAVITATIONAL theories light PROPAGATION ASTROMETRY
A global analysis searching for neutrinos associated with black hole merger gravitational wave events
19
作者 Yu-Zi Yang Jia-Jie Ling +1 位作者 Wei Wang Zhao-Kan Cheng 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2018年第11期11-16,共6页
Several neutrino observatories have searched for coincident neutrino signals associated with gravitational waves induced by the merging of two black holes.No statistically significant neutrino signal in excess of the ... Several neutrino observatories have searched for coincident neutrino signals associated with gravitational waves induced by the merging of two black holes.No statistically significant neutrino signal in excess of the background level was observed.These experiments use different neutrino detection technologies and are sensitive to various neutrino types.A combined analysis was performed on the KamLAND,Super-Kamiokande and Borexino experimental data with a frequentist statistical approach to achieve a global picture of the associated neutrino fluence.Both monochromatic and Fermi-Dirac neutrino spectra were assumed in the calculation.The final results are consistent with null neutrino signals associated with the process of a binary black hole merger.The derived 90%confidence level upper limits on the fluence and luminosity of various neutrino types are presented for neutrino energy less than 110MeV. 展开更多
关键词 GRAVITATIONAL wave black hole MERGER NEUTRINO FLUENCE global analysis
Anomaly Feature Extraction of the Gravity Field before the Jiuzhaigou Earthquake in 2017 预览
20
作者 Liu Fang Zhu Yiqing +1 位作者 Zhao Yunfeng Liu Tao 《中国地震研究:英文版》 CSCD 2018年第4期501-509,共9页
The MS7.0 Jiuzhaigou earthquake occurred on August 8,2017.The earthquake occurred in the vicinity of the Tazang fault,the Minjiang fault and the Huya fault,where the focal mechanism is of the strike slip type.The stat... The MS7.0 Jiuzhaigou earthquake occurred on August 8,2017.The earthquake occurred in the vicinity of the Tazang fault,the Minjiang fault and the Huya fault,where the focal mechanism is of the strike slip type.The static and dynamic anomalies of the gravity field can provide important physical field information for studying the structural properties of deep crust.Multi-scale decomposition techniques are used to separate Bouguer gravity at different depths and give some explanation to gravity variations at different time space scales.The results indicate that the wavelet multi-scale results of the EGM2008 model and the measured gravity data are consistent.Through comparative analysis,it is found that the Jiuzhaigou earthquake occurred in the stress enhanced region.The variation of gravity field at different time scales has a certain scientific significance for further understanding potential earthquake risk trend. 展开更多
关键词 Jiuzhaigou MS7.0 EARTHQUAKE GRAVITATIONAL field WAVELET DECOMPOSITION MULTI-SCALE
在线阅读 免费下载
上一页 1 2 105 下一页 到第
使用帮助 返回顶部 意见反馈