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On joint analysing XMM-NuSTAR spectra of active galactic nuclei
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作者 Jialai Kang Junxian Wang 《中国科学技术大学学报》 CAS CSCD 北大核心 2024年第7期19-33,18,I0002,共17页
A recently released XMM-Newton note revealed a significant calibration issue between nuclear spectroscopic telescope array(NuSTAR)and XMM-Newton European Photon Imaging Camera(EPIC)and provided an empirical correction... A recently released XMM-Newton note revealed a significant calibration issue between nuclear spectroscopic telescope array(NuSTAR)and XMM-Newton European Photon Imaging Camera(EPIC)and provided an empirical correction to the EPIC effective area.To quantify the bias caused by the calibration issue in the joint analysis of XMM-NuSTAR spectra and verify the effectiveness of the correction,in this work,we perform joint-fitting of the NuSTAR and EPIC-pn spectra for a large sample of 104 observation pairs of 44 X-ray bright active galactic nuclei(AGN).The spectra were extracted after requiring perfect simultaneity between the XMM-Newton and NuSTAR exposures(merging good time intervals(GTIs)from two missions)to avoid bias due to the rapid spectral variability of the AGN.Before the correction,the EPIC-pn spectra are systematically harder than the corresponding NuSTAR spectra by■subsequently yielding significantly underestimated cutoff energy E_(cut)and the strength of reflection component R when performing joint-fitting.We confirm that the correction is highly effective and can commendably erase the discrepancy in best-fitΓ,E_(cut),and R.We thus urge the community to apply the correction when joint-fitting XMM-NuSTAR spectra,but note that the correction is limited to 3–12 keV and therefore not applicable when the soft X-ray band data are included.Besides,we show that as merging GTIs from two missions would cause severe loss of NuSTAR net exposure time,in many cases,joint-fitting yields no advantage compared with utilizing NuSTAR data alone.Finally,We present a technical note on filtering periods of high background flares for XMM-Newton EPIC-pn exposures in the small window(SW)mode. 展开更多
关键词 active galactic nuclei X-ray spectroscopy XMM-NEWTON NuSTAR cross-calibration issue
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Bromodimethylsulfonium Bromide Catalyzed Synthesis of Methyl 2-Dexoy-4,6-O-benzylidene Galactopyranoside from Galactal and the Rapid Route to 2,3- and 2,6-Dideoxygalactopyranoses
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作者 Ding,Ning Chun,Yuexing +1 位作者 Zhang,Wei Li,Yingxia 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2012年第2期409-412,共4页
4,6-O-Benzylidenation of D-galactal with PhCH(OCH3)2 catalyzed by bromodimethylsulfonium bromide leads to methyl 2-dexoy-4,6-O-benzylidene galactopyranoside efficiently, which serves as a key intermediate to the rea... 4,6-O-Benzylidenation of D-galactal with PhCH(OCH3)2 catalyzed by bromodimethylsulfonium bromide leads to methyl 2-dexoy-4,6-O-benzylidene galactopyranoside efficiently, which serves as a key intermediate to the ready preparation of 2,3- and 2,6-dideoxy galactopyranosides. 展开更多
关键词 deoxysugars bromodimethylsulfonium bromide synthetic methods galactal CARBOHYDRATE
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Explanation of Two Important Empirical Relations for Galaxies
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作者 Yingqiu Gu 《Journal of Applied Mathematics and Physics》 2024年第1期284-304,共21页
The phenomenon of “missing mass” in galaxies has triggered new theoretical exploration, forming a competition between dark matter assumption, modified Newtonian dynamics and modified gravity. Over the past forty yea... The phenomenon of “missing mass” in galaxies has triggered new theoretical exploration, forming a competition between dark matter assumption, modified Newtonian dynamics and modified gravity. Over the past forty years, various versions of the modified scenario have been proposed to simulate the effects of missing mass. These schemes replace the dynamic effect of dark matter by introducing some tiny extra force terms in the dynamic equations. Such extra forces have mainly interactions on large scales of galaxies, such as fitting the Tully-Fisher relation or asymptotically flat rotation curves. The discussion in this paper shows that the evidence of taking the modified schemes as fundamental theory is still insufficient. In this paper, we display a system of simplified galactic dynamical equations derived from weak field and low-speed approximations of Einstein field equations, and then we use it to discuss two important empirical relations in galactic dynamics, namely the Faber-Jackson relation and Tully-Fisher relation, as well as the related fundamental plane. These discussions provide a reference scheme for improving the dispersion of the empirical relations, and also provide a theoretical foundation to analyze the properties of dark matter and galactic structures. 展开更多
关键词 Galactic Dynamics Faber-Jackson Relation Tully-Fisher Relation Dark Matter MOND
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Dark Matter Density Profiles of Selected Spiral Galaxies
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作者 Alberto Sadun Brittany Salmon +1 位作者 Conor Evans Masoud Asadi-Zeydabadi 《International Journal of Astronomy and Astrophysics》 2024年第3期172-183,共12页
Understanding the dark matter distribution throughout a galaxy can provide insight into its elusive nature. Numerous density profiles, such as the Navarro, Frenk and White model, have been created in an attempt to stu... Understanding the dark matter distribution throughout a galaxy can provide insight into its elusive nature. Numerous density profiles, such as the Navarro, Frenk and White model, have been created in an attempt to study this distribution through analyzing orbital velocities of luminous matter and modeling dark matter distributions to explain these observations. However, we are interested in a simple model to consider the significant fluctuations in rotation curves at larger radii. Therefore, our model is much simpler compared to those previously mentioned. Our model used all the observational data available for four selected galactic rotation curves. These data present a significant variation in the orbital velocity of matter at the same distances. By running real observational data through our model, we show that the density of the dark matter within them shows real complex structure, which is not suggested by other computational models. Our aim of this paper is to model this structure and then speculate as to the cause and implications of these density fluctuations. 展开更多
关键词 Dark Matter Density Galactic Rotation Curves Spiral Galaxies NGC 2841 NGC 4527 NGC 4945 NGC 3198
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The Unified Field
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作者 Joseph H. (Cass) Forrington 《Journal of Modern Physics》 2024年第7期1010-1035,共26页
This is a Unified Field description based on the holographic Time Dilation Cosmology, TDC, model, which is an eternal continuum evolving forward in the forward direction of time, at the speed of light, c, at an invari... This is a Unified Field description based on the holographic Time Dilation Cosmology, TDC, model, which is an eternal continuum evolving forward in the forward direction of time, at the speed of light, c, at an invariant 1 s/s rate of time. This is the Fundamental Direction of Evolution, FDE. There is also an evolution down time dilation gradients, the Gravitational Direction of Evolution, GDE. These evolutions are gravity, which is the evolutionary force in time. Gravitational velocities are compensation for the difference in the rate of time, dRt, in a dilation field, and the dRtis equal to the compensatory velocity’s percentage of c, and is a measure of the force in time inducing the velocity. In applied force induced velocities, the dRt is a measure of the resistance in time to the induced velocity, which might be called “anti-gravity” or “negative gravity”. The two effects keep the continuum uniformly evolving forward at c. It is demonstrated that gravity is already a part of the electromagnetic field equations in way of the dRt element contained in the TDC velocity formula. Einstein’s energy formula is defined as a velocity formula and a modified version is used for charged elementary particle solutions. A time dilation-based derivation of the Lorentz force ties gravity directly to the electromagnetic field proving the unified field of gravity and the EMF. It is noted how we could possibly create gravity drives. This is followed by a discussion of black holes, proving supermassive objects, like massive black hole singularities, are impossible, and that black holes are massless Magnetospheric Eternally Collapsing Objects (MECOs) that are vortices in spacetime. . 展开更多
关键词 Unified Field GRAVITY Anti-Gravity Astrophysics Einstein General Relativity Special Relativity Galactic Rotation Velocities Time Dilation SPACETIME Space Time Spacetime Continuum Quantum Continuum MECO Black Hole Event Horizon Timelike Spacelike Lightlike
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Axion-Photon Conversion of LHAASO Multi-TeV and PeV Photons
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作者 张光帅 马伯强 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第1期19-22,共4页
The Large High Altitude Air Shower Observatory(LHAASO)has reported the detection of a large number of multi-Te V-scale photon events also including several Pe V-scale gamma-ray-photon events with energy as high as 1.4... The Large High Altitude Air Shower Observatory(LHAASO)has reported the detection of a large number of multi-Te V-scale photon events also including several Pe V-scale gamma-ray-photon events with energy as high as 1.4 Pe V.The possibility that some of these events may have extragalactic origins is not yet excluded.Here we propose a mechanism for the traveling of very-high-energy and ultra-high-energy photons based upon the axionphoton conversion scenario,which allows extragalactic above-threshold photons to be detected by observers on the Earth.We show that the axion-photon conversation can serve as an alternative mechanism,besides the threshold anomaly due to Lorentz invariance violation,for the very-high-energy features of the newly observed gamma ray burst GRB 221009A. 展开更多
关键词 TRAVELING LORENTZ GALACTIC
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NASA’s Pioneer Spacecraft Anomaly, Heat, Dark Matter and a Probable Persuasive Genesis
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作者 Leandro Meléndez Lugo Esteban Chávez Alarcón 《Journal of High Energy Physics, Gravitation and Cosmology》 2023年第4期1356-1373,共18页
An analysis is performed on what is known as the anomaly of NASA’s probe spacecraft. It explains why this additional acceleration can hardly be caused by the heat emitted by the electronic equipment of the spacecraft... An analysis is performed on what is known as the anomaly of NASA’s probe spacecraft. It explains why this additional acceleration can hardly be caused by the heat emitted by the electronic equipment of the spacecraft or by the dark matter that the Solar System could contain. Additionally, the correct stellar dynamics are mathematically demonstrated to explain the high speed of stellar rotation directly in galaxies and to show that this dynamics governing galaxies is very different from the dynamics of the Solar System. This also demonstrates the superfluity of postulating the existence of Dark Matter at the galactic level. It is concluded that the anomaly of the Pioneer spacecraft is relatively feasible as a product of an explainable difference between the modeling of the 70s and the real sources of the gravitational field of the Solar System. Therefore, it is claimed that there were sources of gravitational field that were not included in the original modeling because they were unknown at the time. Finally, a particular distribution of the disperse Solar System mass is proposed that could represent the sources of the field that give a plausible explanation for the NASA spacecraft anomaly. 展开更多
关键词 Dark Matter Pioneers 10 and 11 Galactic Radial Velocity GRAVITATION Radiation Pressure
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Astrophysical Applications of a Variant to Kepler’s Third Law
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作者 John Nicholas Beery 《Journal of High Energy Physics, Gravitation and Cosmology》 2023年第3期835-849,共15页
It is verified that the Nebula Hypothesis is applicable to the Solar System by way of a straightforward generalization of Kepler’s third law which also confirms that angular momentum transport is achieved by way of t... It is verified that the Nebula Hypothesis is applicable to the Solar System by way of a straightforward generalization of Kepler’s third law which also confirms that angular momentum transport is achieved by way of the self-gravity of the protoplanetary disk itself as it coalesces into planetesimals. The masses of the planets may then be approximately determined (within 10% error, for three planets) by way of this methodology, using the radius as well as the rate of rotation of the particular planet being considered. This would only be possible, not only in light of the Nebula Hypothesis, but also due to angular momentum transport (as these three planets most ideally express the expectations of angular momentum conservation from the protoplanetary disk). Also in this regard, the rotation of the Sun at its equator is discussed as it is found to be closely related to the planetary issue as it pertains to the evolution and structure of the body. A modified technique from that used in planetary study is then applied to the Galaxy for the purpose of the calculation of dark matter mass, presupposes treating the Galaxy as a homogeneous sphere (of dark matter) that is rotating. The model provides clear evidence of not only flat rotation-curves, but also the lack of centrifugal ejection of stars from galaxies as well as the configuration of the arms of spiral galaxies, along with a sound basis for black hole creation at the center of spiral galaxies. 展开更多
关键词 Planet Formation Nebula Hypothesis Conservation of Angular Momentum Rotation of the Sun at the Equator Dark Matter Galactic Dynamics and Structure
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基于GSO与加权质心的DV-Hop定位算法 被引量:4
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作者 范时平 罗丹 刘艳林 《仪表技术与传感器》 CSCD 北大核心 2017年第1期164-168,共5页
由于经典DV-Hop定位算法中定位精度较低,提出一种改进算法。首先,未知节点计算到各信标节点的距离时,采用不同平均每跳距离。其次,采用GSO(galactic swarm optimization)思想把网络中的信标节点分为不同种群,使用粒子群优化算法估计每... 由于经典DV-Hop定位算法中定位精度较低,提出一种改进算法。首先,未知节点计算到各信标节点的距离时,采用不同平均每跳距离。其次,采用GSO(galactic swarm optimization)思想把网络中的信标节点分为不同种群,使用粒子群优化算法估计每个种群中未知节点的最优位置,其最优位置构成一组次优解集。最后,利用加权质心算法优化次优解集作为未知节点的坐标。实验仿真表明,该方法能有效降低未知节点的定位误差。 展开更多
关键词 无线传感器网络 DV-HOP 跳距选择 粒子群算法 GALACTIC swarm optimization 加权质心算法
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Status of the Hard X-ray Modulation Telescope Project 被引量:2
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作者 LU Fangjun 《空间科学学报》 CAS CSCD 北大核心 2014年第5期544-546,共3页
The Hard X-ray Modulation Telescope(HXMT) is China's first astronomical satellite.It will perform a broad band(1–250 keV) scan survey and do pointed observations of X-ray sources to study their spectra and multi-... The Hard X-ray Modulation Telescope(HXMT) is China's first astronomical satellite.It will perform a broad band(1–250 keV) scan survey and do pointed observations of X-ray sources to study their spectra and multi-wavelength temporal properties. The pre-flight models of the satellites have been finished, and the flight models are in production. The expected launch date of HXMT is in late 2015. 展开更多
关键词 HARD X-ray MODULATION Telescope(HXMT) Astronomical satellite Active GALACTIC NUCLEI
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Studies of the radiation environment on the Mars surface using the Geant4 toolkit 被引量:2
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作者 Jun-Liang Chen Su-Jun Yun +2 位作者 Tie-Kuang Dong Zhong-Zhou Ren Xiao-Ping Zhang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第1期120-130,共11页
The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet.In this study,a simple geometrical model was built for simulating the radiation environment ... The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet.In this study,a simple geometrical model was built for simulating the radiation environment on the Mars surface caused by galactic cosmic rays;the model was built and studied using the Geant4 toolkit.The simulation results were compared with the data reported by a radiation assessment detector(RAD).The simulated spectra of neutrons,photons,protons,α particles,and particle groups Z=3-5,Z=6-8,Z=9-13,and Z=14-24 were in a reasonable agreement with the RAD data.However,for deuterons,tritons,and 3He,the simulations yielded much smaller values than for the corresponding RAD data.In addition,the particles’spectra within the 90 zenith angle were also obtained.Based on these spectra,we calculated the radiation dose that would have been received by an average human body on Mars.The distribution of the dose throughout the human body was not uniform.The absorbed and equivalent doses for the brain were the highest among all of the organs,reaching 62.0±1.7 mGy/y and 234.1±8.0 mSv/y,respectively.The average absorbed and equivalent doses for the entire body were approximately 44 mGy/y and 153 mSv/y,respectively.Further analysis revealed that most of the radiation dose was owing to a particles,protons,and heavy ions.We then studied the shielding effect of the Mars soil with respect to the radiation.The body dose decreased significantly with increasing soil depth.At the depth of 1.5 m,the effective dose for the entire body was 17.9±2.4 mSv/y,lower than the dose limit for occupational exposure.At the depth of 3 m,the effective dose to the body was 2.7±1.0 mSv/y,still higher than the accepted dose limit. 展开更多
关键词 Galactic cosmic rays Radiation environment of the Mars Absorbed dose Equivalent dose GEANT4
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Do Near-Solar-System Supernovae Enhance Volcanic Activities on Earth and Neighbouring Planets on Their Paths through the Spiral Arms of the Milky Way, and What Might Be the Consequences for Estimations of Earth’s History and Predictions for Its Future? 被引量:3
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作者 Heinz-Juergen Brink 《International Journal of Geosciences》 2019年第5期563-575,共13页
Recent observations of young volcanism on the near-Earth terrestrial planets require a new understanding. Magmatic/volcanic episodes on Venus, Mars and Mercury, as well as on Earth’s Moon, are apparently contemporane... Recent observations of young volcanism on the near-Earth terrestrial planets require a new understanding. Magmatic/volcanic episodes on Venus, Mars and Mercury, as well as on Earth’s Moon, are apparently contemporaneous thermal events that accompanied increased magmatic/volcanic activity on Earth, following a 300-Myr cycle. A collateral galactic thermal source in the Milky Way appears to be needed that would predominantly affect the interior of the planets and, perhaps indirectly, Earth’s biosphere, compared to other galactic sources, such as intense cosmic rays or large, rocky bolides. The search for such a source leads to near-Earth supernovae, with their neutrino output, and to the question of whether those neutrinos could act as energy transmitters to heat up the body of Earth, and also enhance its short-term magmatic processes;for example, Cenozoic anorogenic volcanism. This observation challenges present assumptions and paradigms about Earth’s history, and requires the following reconsiderations: 1) the real origin of the end-Cretaceous mass extinction;2) the general radioactive age determinations of rocks;and 3) geodynamic modelling using additional, external heat sources. 展开更多
关键词 Synchronous Planetary MAGMATISM Galactic Heat Source SUPERNOVAE and White DWARFS NEUTRINOS Mass EXTINCTIONS
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Single planet formation regime in the high-ionization environment:Possible origin of hot Jupiters and super-Earths 被引量:1
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作者 Yusuke Imaeda Toshikazu Ebisuzaki 《Geoscience Frontiers》 SCIE CAS CSCD 2018年第4期1023-1031,共9页
We studied the particle growth in a protoplanetary disk in a high-ionization environment and found that icy planet formation is inactive for a disk with an ionization rate 100 times higher than that of the present Sol... We studied the particle growth in a protoplanetary disk in a high-ionization environment and found that icy planet formation is inactive for a disk with an ionization rate 100 times higher than that of the present Solar System. In particular, in the case of M 〈 10^(-7.4)M_☉yr^(-1), only rocky planet formation occurs. In such a case, all the solid materials in the disk drift inward, eventually reach the inner MRI front,and accumulate there. They form a dense, thin sub-disk of solid particles, which undergoes gravitational instability to form rocky planetesimals. The planetesimals rapidly grow into a planet through pebble accretion. Consequently, rocky planets tend to be much larger than planets formed through other regimes(tandem planet formation regime and dispersed planet formation regime), in which icy planet formation actively takes place. These rocky planets may evolve into hot Jupiters if they grow fast enough to the critical core mass of the runaway gas accretion before the dispersal of the disk gas, or they may evolve into super-Earths if the gas dispersed sufficiently early. 展开更多
关键词 Accretion disk Planet formation Magneto-rotational instability Galactic cosmic rays Hot Jupiter Super-Earth
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Radio spectral index from NVSS and TGSS 被引量:1
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作者 Prabhakar Tiwari 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第7期59-66,共8页
I extract the radio spectral index,α,from 541 195 common sources observed in the 150 MHz TIFR GMRT Sky Survey(TGSS) and the 1.4 GHz NRAO VLA Sky Survey(NVSS).This large common source catalog covers about 80% of the s... I extract the radio spectral index,α,from 541 195 common sources observed in the 150 MHz TIFR GMRT Sky Survey(TGSS) and the 1.4 GHz NRAO VLA Sky Survey(NVSS).This large common source catalog covers about 80% of the sky.The flux density limits in these surveys are such that the observed galaxies are presumably hosts of active galactic nuclei(AGNs).I confirm the steepening of αwith increasing flux density for this large sample and provide a parametric fit between α and flux density.Next,I divide the data into low flux(LF) and high flux(HF) density samples with roughly equal numbers of galaxies.The LF sample contains all galaxies below 100 m Jy TGSS and 20 m Jy NVSS flux density and the HF sample is all galaxies above 100 m Jy TGSS and 20 m Jy NVSS.I observe an increase in α with source size(TGSS measured),saturating for large sizes to 0.89 ± 0.22 and 0.76 ± 0.21 for the LF and HF sources,respectively.I discuss the observed results and possible physical mechanisms to explain observedα dependence with source size for LF and HF samples. 展开更多
关键词 galaxies:high-redshift galaxies:active GALACTIC NUCLEI
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The THU-NAOC transient survey: the performance and results from the first year 被引量:1
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作者 Tian-Meng Zhang Xiao-Feng Wang +18 位作者 Jun-Cheng Chen Ju-Jia Zhang Li Zhou Wen-Xiong Li Qing Liu Jun Mo Kai-Cheng Zhang Xin-Yu Yao Xu-Lin Zhao Xu Zhou Jun-Dan Nie Fang Huang Zhao-Ji Jiang Jun Ma Ling-Zhi Wang Chao Wu Zhi-Min Zhou Hu Zou Li-Fan Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第2期215-224,共10页
The Tsinghua University-National Astronomical Observatories, Chinese Academy of Sciences (NAOC) Transient Survey is an automatic survey that conducts a systematic exploration of optical transients. This project util... The Tsinghua University-National Astronomical Observatories, Chinese Academy of Sciences (NAOC) Transient Survey is an automatic survey that conducts a systematic exploration of optical transients. This project utilizes a 60/90 cm Schmidt telescope at the Xinglong Station of NAOC. This survey repeatedly covers - 1000 square degrees of the northern sky with a cadence of 34 d. With an exposure of 60 s, the survey reaches a limiting unfiltered magnitude of about 19.5 mag, which enables us to discover supernovae in their relatively young stages. We describe the overall performance of our survey during the first year and present some preliminary results. 展开更多
关键词 SUPERNOVAE quasars and active galactic nuclei STARS
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Debates on the Causes of Global Warming 被引量:1
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作者 HUANG Jian-Bin WANG Shao-Wu +2 位作者 LUO Yong ZHAO Zong-Ci WEN Xin-Yu 《Advances in Climate Change Research》 SCIE 2012年第1期38-44,共7页
The controversy between the IPCC and Non-governmental IPCC(NIPCC) on the attribution of global warming are reviewed.IPCC holds that today's global warming is mainly due to anthropogenic activities rather than natu... The controversy between the IPCC and Non-governmental IPCC(NIPCC) on the attribution of global warming are reviewed.IPCC holds that today's global warming is mainly due to anthropogenic activities rather than natural variability,which is emphasized by NIPCC.The surface temperature observations since the mid-20th century support the hypothesis of anthropogenic impact,but for the last one hundred years or so,natural forcings such as solar activity, volcanic eruptions and thermohaline circulation variations also have had great influences on the Earth's climate,especially on inter-decadal timescales.In addition,evidence suggests that the Medieval Warm Period(MWP) and Little Ice Age (LIA) are closely associated with the solar activity over the past 1 thousand years.Over the past 10 thousand years, the North Atlantic cold events and solar activity are closely correlated.Nevertheless,the physical mechanisms of the solar-climate variability and interrelation are not well understood,yet.Notably,a prevailing view recently indicates that galactic cosmic rays may result in climatic cooling through modulating global low cloud cover.However,its process and mechanism need to be further investigated. 展开更多
关键词 global warming CAUSES greenhouse effect solar activity galactic cosmic rays
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35 Ma-An Important Natural Periodicity in Geological History: Concept of Natural Crisis and Its Possible Cause 被引量:1
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作者 Shi Xiaoying(Department of Geology and Mineral Resources, China Universily of Geosciences, Beijing 100083) 《Journal of Earth Science》 SCIE CAS CSCD 1996年第2期147-155,共9页
Among the cyclicity shown by the geologic evolution of the earth, the periodicity of ca 35 Ma is expressed most distinctly, which is evidenced not only by global sea-level changes, biotic mass extinctions, tectonic ep... Among the cyclicity shown by the geologic evolution of the earth, the periodicity of ca 35 Ma is expressed most distinctly, which is evidenced not only by global sea-level changes, biotic mass extinctions, tectonic episodes, magmatic cycles and climatic changes. but also by magnetic reversals and impact craterings. It is suggested that the periodicity of ca 35 Ma may represent a natural stage by which the earth has evolved, and can be taken as an objective criterion of determining the 2nd-order eustatic cycles and their sedimentary records-the mesosequences. Major geologic events in the earth's history are apparently clustered at some specific periods, suggesting natural crises. They are thought to have been controlled mainly by astronomic cycles. especially related to the crossing of the Solar system through the Calactic plane. 展开更多
关键词 Ma. natural cycle. natural crisis galactic crossing
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Formation and Evolution of Galaxies and Black Holes 被引量:1
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作者 Cui-xiang Zhong 《Journal of Physical Science and Application》 2018年第1期23-29,共7页
In the past,people did not realize the formation and structure of galaxies.They even mistook the black holes hidden in the center of a galaxy as independent celestial objects,making black holes mysterious and unbeliev... In the past,people did not realize the formation and structure of galaxies.They even mistook the black holes hidden in the center of a galaxy as independent celestial objects,making black holes mysterious and unbelievable.It was only after the author studied and discovered the laws of the formation and evolution of satellites,planets and stars that he put forward the scientific theory of galaxy formation and evolution,therefore revealing the hierarchical structure of galaxy and the existence and characteristics of black holes as the main nodes of galactic structure. 展开更多
关键词 GALACTIC structure GALAXY FORMATION GALAXY EVOLUTION BLACK holes BLACK hole area
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Detection of a high-confidence quasi-periodic oscillation in radio light curve of the high redshift FSRQ PKS J0805–0111 被引量:1
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作者 Guo-Wei Ren Hao-Jing Zhang +5 位作者 Xiong Zhang Nan Ding Xing Yang Fu-Ting Li Pei-Lin Yan Xiao-Lin Xu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第3期243-250,共8页
In this work,we have searched for quasi-periodic oscillations(QPOs)in the 15 GHz light curve of the FSRQ PKS J0805-0111 monitored by the Owens Valley Radio Observatory(OVRO)40 m telescope during the period from 2008 J... In this work,we have searched for quasi-periodic oscillations(QPOs)in the 15 GHz light curve of the FSRQ PKS J0805-0111 monitored by the Owens Valley Radio Observatory(OVRO)40 m telescope during the period from 2008 January 9 to 2019 May 9,using the weighted wavelet Z-transform(WWZ)and the Lomb-Scargle Periodogram(LSP)techniques.This is the first time to search for a periodic radio signal in the FSRQ PKS J0805-0111 by these two methods.Both methods consistently reveal a repeating signal with a periodicity of 3.38±0.8 yr(>99.7%confidence level).In order to determine the significance of the periods,the false alarm probability method was applied,and a large number of Monte Carlo simulations were performed.As possible explanations,we discuss a number of scenarios including the thermal instability of thin disks scenario,the spiral jet scenario and the binary supermassive black hole scenario.We expect that the binary black hole scenario,where the QPO is caused by the precession of binary black holes,is the most likely explanation.FSRQ PKS J0805-0111 thus could be a good binary black hole candidate.In the binary black hole scenario,the distance between the primary black hole and the secondary black hole is about 1.71×10^(16) cm. 展开更多
关键词 active galactic nuclei:flat spectrum radio quasar:individual:PKS J0805–0111 galaxies:jets method:time series analysis
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Dark Matter Cosmology and Astrophysics 被引量:8
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作者 Vladimir S. Netchitailo 《Journal of High Energy Physics, Gravitation and Cosmology》 2019年第4期999-1050,共52页
Hypersphere World-Universe Model (WUM) envisions Matter carried from Universe into World from fourth spatial dimension by Dark Matter Particles (DMPs). Luminous Matter is byproduct of Dark Matter (DM) annihilation. WU... Hypersphere World-Universe Model (WUM) envisions Matter carried from Universe into World from fourth spatial dimension by Dark Matter Particles (DMPs). Luminous Matter is byproduct of Dark Matter (DM) annihilation. WUM introduces Dark Epoch (spanning from Beginning of World for 0.4 billion years) when only DMPs existed, and Luminous Epoch (ever since for 13.8 billion years). Big Bang discussed in standard cosmological model is, in our view, transition from Dark Epoch to Luminous Epoch due to Rotational Fission of Overspinning DM Supercluster’s Cores and annihilation of DMPs. WUM solves a number of physical problems in contemporary Cosmology and Astrophysics through DMPs and their interactions: Angular Momentum problem in birth and subsequent evolution of Galaxies and Extrasolar systems—how do they obtain it;Fermi Bubbles—two large structures in gamma-rays and X-rays above and below Galactic center;Mysterious Star KIC 8462852 with irregular dimmings;Coronal Heating problem in solar physics—temperature of Sun’s corona exceeding that of photosphere by millions of degrees;Cores of Sun and Earth rotating faster than their surfaces;Diversity of Gravitationally-Rounded Objects in Solar system and their Internal Heat;Lightning Initiation problem—electric fields observed inside thunderstorms are not sufficient to initiate sparks;Terrestrial Gamma-Ray Flashes—bursts of high energy X-rays and gamma rays emanating from Earth. Model makes predictions pertaining to Masses of DMPs, proposes New Types of their Interactions. WUM reveals Inter-Connectivity of Primary Cosmological Parameters and calculates their values, which are in good agreement with the latest results of their measurements. 展开更多
关键词 Hypersphere World-Universe Model Law of Conservation of Angular Momentum DARK EPOCH Rotational Fission Luminous EPOCH Multiworld DARK MATTER Particles Macroobject Shell Model DARK MATTER Core Medium of the World Mysterious Star KIC 8462852 DARK MATTER Fermi Bubbles Solar CORONA Geocorona Planetary CORONA Galactic Wind Solar Wind High-Energy Atmospheric Physics Lightning Initiation Problem Terrestrial GAMMA-RAY Flashes GAMMA-RAY BURSTS Gravitational BURSTS Ball Lightning
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