期刊文献+

《Chinese Journal of Astronomy and Astrophysics》

作品数636被引量426H指数9
本刊1981年创刊至2000年已出版20卷。创刊时为中文期刊,2001年改为英文刊。主要刊登天文学和天体物理学领域的原创性研究论文。主要栏目和报道范围:“研究快报”用来报道天文观测的新结果及新理论;“...查看详情>>
  • 主办单位北京天文学会;北京天文台
  • 国际标准连续出版物号1009-9271
  • 国内统一连续出版物号11-4631/P
  • 出版周期双月刊
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Non-thermal emission from Vela X and PWN G0.9+0.1
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作者 Wei-Fan Qiao Li Zhang Jun Fang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第4期449-456,共8页
We study the multi-waveband non-thermal emission from the pulsar wind nebulae (PWNe) Vela X and G0.9+0.1 in the frame of a time-dependent model describing non-thermal radiation from the PWNe. In such a model, the r... We study the multi-waveband non-thermal emission from the pulsar wind nebulae (PWNe) Vela X and G0.9+0.1 in the frame of a time-dependent model describing non-thermal radiation from the PWNe. In such a model, the relativistic wind of particles driven by a central pulsar blows into the ambient medium and creates a termination shock that accelerates the particles to very high energy in a PWN. The non-thermal photons in the PWN are produced both by synchrotron radiation and the inverse Compton process, with electrons coming directly from the pulsar magnetosphere and electrons being accelerated at the termination shock. We apply this model to reproduce the observed multi-waveband photon spectra of Vela X and the G0.9+0.1, both of which have been detected emitting very high energy photons. Our results indicate that TeV photons are produced by the inverse Compton scattering of the high-energy electrons in the infrared photon field in both Vela X and PWN G0.9+0.1. The TeV photons from these two PWNe may have leptonic origins. 展开更多
关键词 ISM individual objects Vela X G0.9 0.1-gamma-rays THEORY
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Luminosity Function of the Cluster of Galaxies Abell 566 被引量:1
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作者 Quan-Bao Xiao Zheng-Yi Shao Xu Zhou 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第5期620-628,共9页
We investigate the Luminosity Function (LF) of the cluster of galaxies Abell 566. The photometric data of 15 intermediate-bands are obtained from the Beijing-Arizona- Taiwan-Connecticut (BATC) photometric sky surv... We investigate the Luminosity Function (LF) of the cluster of galaxies Abell 566. The photometric data of 15 intermediate-bands are obtained from the Beijing-Arizona- Taiwan-Connecticut (BATC) photometric sky survey. For each of the 15 wavebands, the LF of cluster galaxies is well modelled by the Schechter function, with characteristic luminosities from -18.0 to -21.9 magnitude, from the α- to the p-band. Morphological dependence of the LF is investigated by separating the cluster members into 'red' and 'blue' subsamples. It is clear that late type galaxies have a steeper shape of LF than the early type galaxies. We also divided the sample galaxies by their local environment. It was found that galaxies in the sparser region have steeper shape of LF than galaxies in the denser region. Combining the results of morphological and environmental dependence of LFs, we show that Abell 566 is a well relaxed cluster with positive evidence of galaxy interaction and merger, and excess number of bright early type galaxies located in its denser region. 展开更多
关键词 GALAXY CLUSTER INDIVIDUAL Abell 566 -- galaxy photometry -- galaxy lumi- nosity function
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Simulation Study on High Energy Cosmic Electron Detection by Shower Image
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作者 Rong Xu Jin Chang +3 位作者 S. Torii K. Kasahara T. Tamura K. Yoshida 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第6期839-844,共6页
Many projects have recently been carried out and proposed for observing high energy electrons since it is realized that cosmic ray electrons are very important when studying the dark matter particles and the accelerat... Many projects have recently been carried out and proposed for observing high energy electrons since it is realized that cosmic ray electrons are very important when studying the dark matter particles and the acceleration mechanism of cosmic rays. An imaging calorimeter, BETS (Balloon-borne Electron Telescope with Scintillator fiber), has been developed for this purpose. Using pattern analysis of the shower development, the electrons can be selected from those primary cosmic ray proton events with flux heights one-tenth that of the electrons. The Monte-Carlo simulation is indispensable for the instrument design, the signal trigger and the data analysis. We present different shower simulation codes and compare the simulation results with the beam test and the flight data of BETS. We conclude that the code FLUKA2002 gives the most consistent results with the experimental data. 展开更多
关键词 METHODS analytical -- Monte-Carlo simulation -- cosmic rays
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Membership and Segregation Effects in the Young Open Cluster NGC 6530
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作者 Jun-Liang Zhao Li Chen Wen Wen 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2006年第4期435-446,共12页
From photographic plate data of Shanghai Astronomical Observatory with a time baseline of 87 years, proper motions and membership probabilities of 364 stars in the open cluster NGC 6530 region are reduced. On the basi... From photographic plate data of Shanghai Astronomical Observatory with a time baseline of 87 years, proper motions and membership probabilities of 364 stars in the open cluster NGC 6530 region are reduced. On the basis of membership determination, luminosity function and segregation effect of the cluster are discussed with details. Spatial mass segregation is obviously present in NGC 6530 while there is no clear evidence for a velocity-mass (or velocity-luminosity)dependence. The observed spatial mass segregation for NGC 6530 might be due to a combination of initial conditions and relaxation process. 展开更多
关键词 open clusters and associations: individual (NGC 6530)
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The Guest Star of AD185 must have been a Supernova 被引量:1
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作者 Fu-Yuan Zhao R. G. Strom Shi-Yang Jiang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2006年第5期635-640,共6页
The "guest star" of AD185, recorded in the ancient Chinese history the Houhanshu, has been widely regarded as a supernova. However, some authors have suggested that the guest star might have been a comet. It has als... The "guest star" of AD185, recorded in the ancient Chinese history the Houhanshu, has been widely regarded as a supernova. However, some authors have suggested that the guest star might have been a comet. It has also been proposed that the record is the concatenation of a nova with a comet made by an early compiler. We have checked the record of the guest star, comparing it with records of comets in the same history. We find that most descriptions of comets clearly indicate motion, whereas the record of the guest star does not. We further argue that the term "yan" used to describe the star's "size" might be short for yanchuang (seat bed), and "half a yan" would be simply as an imaginary figuration of the ancient observer. Moreover, we show that the term "hou -year" (hou-nian) most probably means the year after next. We argue that the asterism Southern Gate consisted of the stars α andβ Cen. We conclude that the record describing the guest star of AD 185 is completely different from any comet record in the same history, and that it almost certainly was a supernova. 展开更多
关键词 history of astronomy -- guest star -- stars SUPERNOVA individual (SN185)
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Spin Evolution of Neutron Stars in OB/X-ray Binaries 被引量:1
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作者 FanZhang Xiang-DongLi Zhen-RuWang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2004年第4期320-334,共15页
We have investigated the relation between the orbital period P<SUB>orb</SUB> and the spin period P<SUB>s</SUB> of neutron stars in OB/X-ray binaries. By simulating the time-development of the m... We have investigated the relation between the orbital period P<SUB>orb</SUB> and the spin period P<SUB>s</SUB> of neutron stars in OB/X-ray binaries. By simulating the time-development of the mass loss rate and radius expansion of a 20M<SUB>☉</SUB> donor star, we have calculated the detailed spin evolution of the neutron star before steady wind accretion occurs (that is, when the break spin period is reached), or when the OB star begins evolving off the main sequence or has filled its Roche lobe. Our results are compatible with the observations of OB/X-ray binaries. We find that in relatively narrow systems with orbital periods less than tens of days, neutron stars with initial magnetic field B<SUB>0</SUB> stronger than about 3&#x00d7;10<SUP>12</SUP> G can reach the break spin period to allow steady wind accretion in the main sequence time, whereas neutron stars with B<SUB>0</SUB> < 3&#x00d7;10<SUP>12</SUP> G and/or in wide systems would still be in one of the pulsar, rapid rotator or propeller phases when the companion evolves off the main sequence or fills its Roche lobe. Our results may help understand the various characteristics of the observed OB/neutron star binaries along with their distributions in the P<SUB>s</SUB>-P<SUB>orb</SUB> diagram. 展开更多
关键词 binaries: close stars: evolution stars: pulsars stars: supergiants stars:winds OUTFLOWS
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The Prediction of Maximum Amplitudes of Solar Cycles and the Maximum Amplitude of Solar Cycle 24 被引量:8
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作者 Jia-Long Wang, Jian-Cun Gong, Si-Qing Liu, Gui-Ming Le and Jing-Lan Sun1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 1000122 Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2002年第6期557-562,共6页
We present a brief review of predictions of solar cycle maximum amplitude with a lead time of 2 years or more. It is pointed out that a precise prediction of the maximum amplitude with such a lead-time is still an ope... We present a brief review of predictions of solar cycle maximum amplitude with a lead time of 2 years or more. It is pointed out that a precise prediction of the maximum amplitude with such a lead-time is still an open question despite progress made since the 1960s. A method of prediction using statistical characteristics of solar cycles is developed: the solar,cycles are divided into two groups, a high rising velocity (HRV) group and a low rising velocity (LRV) group, depending on the rising velocity in the ascending phase for a given duration of the ascending phase. The amplitude of Solar Cycle 24 can be predicted after the start of the cycle using the formula derived in this paper. Now, about 5 years before the start of the cycle, we can make a preliminary prediction of 83.2-119.4 for its maximum amplitude. 展开更多
关键词 Sun : sunspots Sun : activity
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Study of white-light flares observed by Hinode
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作者 Hai-Min Wang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第2期127-132,共6页
White-light flares are considered to be the most energetic flaring events that are observable in the optical broad-band continuum of the solar spectrum. They have not been commonly observed. Observations of white-ligh... White-light flares are considered to be the most energetic flaring events that are observable in the optical broad-band continuum of the solar spectrum. They have not been commonly observed. Observations of white-light flares with sub-arcsecond resolution have been very rare. The continuous high resolution observations of Hinode provide a unique opportunity to systematically study the white-light flares with a spatial resolution around 0.2 arcsec. We surveyed all the flares above GOES magnitude C5.0 since the launch of Hinode in 2006 October. 13 of these kinds of flares were covered by the Hinode G-band observations. We analyzed the peak contrasts and equivalent areas (calculated via integrated excess emission contrast) of these flares as a function of the GOES X-ray flux, and found that the cut-off visibility is likely around M1 flares under the observing limit of Hinode. Many other observational and physical factors should affect the visibility of white-light flares; as the observing conditions are improved, smaller flares are likely to have detectable white-light emissions. We are cautious that this limiting visibility is an overestimate, because G-band observations contain emissions from the upper atmosphere. Among the 13 events analyzed, only the M8.7 flare of 2007 June 4 had near-simultaneous observations in both the G-band and the blue continuum. The blue continuum had a peak contrast of 94% vs. 175% in G-band for this event. The equivalent area in the blue continuum is an order of magnitude lower than that in the G-band. Very recently, Jess et al. studied a C2.0 flare with a peak contrast of 300% in the blue continuum. Compared to the events presented in this letter, that event is probably an unusual white-light flare: a very small kernel with a large contrast that can be detected in high resolution observations. 展开更多
关键词 SUN activity - Sun flares - Sun magnetic fields
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Relationship between CME velocities and X-ray fluxes of associated flares 被引量:3
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作者 An-Qin Chen Wei-Guo Zong 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第4期470-474,共5页
Coronal mass ejection (CME) velocities have been studied over recent decades. We present a statistical analysis of the relationship between CME velocities and X-ray fluxes of the associated flares. We study two type... Coronal mass ejection (CME) velocities have been studied over recent decades. We present a statistical analysis of the relationship between CME velocities and X-ray fluxes of the associated flares. We study two types of CMEs. One is the FL type associated only with flares, while the other is the intermediate type associated with both filament eruptions and flares. It is found that the velocities of the FL type CMEs are strongly correlated with both the peak and the time-integrated X-ray fluxes of the associated flares. However, the correlations between the intermediate type CME velocities and the corre- sponding two parameters are poor. It is also found that the correlation between the CME velocities and the peak X-ray fluxes is stronger than that between the CME velocities and the time-integrated X-ray fluxes of the associated flares. 展开更多
关键词 SUN coronal mass ejections (CMEs)-Sun flares-Sun FILAMENTS
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Asteroseismic Analysis ofαCen B:Preliminary Tests of Effects of Rotation and Interior Magnetic Field in the Solar-like Star
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作者 Yan-Ke Tang Shao-Lan Bi +1 位作者 Ning Gai Hua-Yin XU 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2008年第4期421-432,共12页
Taking into consideration the effects of rotation and interior magnetic field during the lifetime of the star, we reconstruct the model of α Cen B to satisfy the latest nonasteroseismic and asteroseismic observationa... Taking into consideration the effects of rotation and interior magnetic field during the lifetime of the star, we reconstruct the model of α Cen B to satisfy the latest nonasteroseismic and asteroseismic observational constraints. We find that the effects can induce a change of about 0.3 μHz in the large frequency spacings and can speed up the star's evolution. The model of a Cen B has thereby been improved. 展开更多
关键词 STARS oscillations - stars interiors - stars individual (α Cen B)
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X-Ray Afterglows of GRBs 050318 and 060124 and their External Shock Origin
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作者 Jin Zhang Yi-Ping Qin +1 位作者 Fu-Wen Zhang Bin-Bin Zhang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第4期516-520,共5页
The observations with Swift X-ray telescope (XRT) challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segme... The observations with Swift X-ray telescope (XRT) challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segment, a shallow decay segment, a normal decay segment, a jet-like steep decay segment, and sometimes erratic flares as well. The physical origin of the X-ray emission is highly debatable. We focus here on the physical origin of the X-ray emissions of GRBs 050318 and 060124. We present the XRT light curves and spectra of the two bursts. The light curve decay slopes of the two bursts are normal, and their relations to the spectral indices are consistent with the prediction of the standard forward shock model. The multi-wavelength light curves at 0.5 keV, 1.0 keV, 2.0 keV and 4.0 keV can be reproduced by this model with an isotropic kinetic energy Ek = 2.2 × 10^52 erg, εe = 0.04, εB = 0.01 for GRB 050318 and Ek = 4.2 × 10^53 erg, εe = 0.05, εB = 0.01 for GRB 060124. These facts suggest that the normal decay phases of the X-rays for the two bursts are of the forward shock origin. 展开更多
关键词 gamma-rays- bursts-individual: GRB 050318 GRB 060124
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Estimating Black Hole Masses of AGNs using Ultraviolet Emission Line Properties 被引量:1
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作者 Min-Zhi Kong Xue-Bing Wu +1 位作者 Ran Wang Jin-Lin Han 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2006年第4期396-410,共15页
Based on measured broad line region sizes in the reverberation-mapping AGN sample, two new empirical relations are introduced to estimate the central black hole masses of radio-loud high-redshift (z 〉 0.5) AGNs. Fi... Based on measured broad line region sizes in the reverberation-mapping AGN sample, two new empirical relations are introduced to estimate the central black hole masses of radio-loud high-redshift (z 〉 0.5) AGNs. First, using the archival IUE/HST spectroscopy data at UV band for the reverberation-mapping objects, we obtained two new empirical relations between the BLR size and Mg Ⅱ/C Ⅳ emission line luminosity. Secondly, using the newly determined black hole masses of the reverberation-mapping sample as calibration, we found two new relationships for determining the black hole mass with the full width at half maximum and the luminosity of Mg Ⅱ/C Ⅳ line. We then apply the relations to estimate the black hole masses of the AGNs in the Large Bright Quasar Survey and a sample of radio-loud quasars. For the objects with small radio-loudness, the black hole mass estimated using the RBLR-LMg Ⅱ/C Ⅳ relation is consistent with that from the RBLR-L3000 A/1350 A relation. For radio-loud AGNs, however, the mass estimated from the RBLR-LMg Ⅱ/C Ⅳ relation is systematically lower than that from the continuum luminosity L3000 A/13S0 A Because jets could have significant contributions to the UV/optical continuum luminosity of radio-loud AGNs, we emphasize once again that for radio-loud AGNs, the emission line luminosity may be a better tracer of the ionizing luminosity than the continuum luminosity, so that the relations between the BLR size and UV emission line luminosities should be used to estimate the black hole masses of high redshift radio-loud AGNs. 展开更多
关键词 galaxies: nucleus -- galaxies: high-redshift-- quasars: emission lines -- ultraviolet: galaxies
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A Parametric Survey of the CME Triggering Process by Numerical Simulations 被引量:2
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作者 Xiao-Yan Xu Peng-Fei Chen Cheng Fang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2005年第6期636-644,共9页
Observations indicate that solar coronal mass ejections (CMEs) are closely associated with reconnection-favored flux emergence, which was explained in the emerging flux trigger mechanism for CMEs by Chen & Shibata ... Observations indicate that solar coronal mass ejections (CMEs) are closely associated with reconnection-favored flux emergence, which was explained in the emerging flux trigger mechanism for CMEs by Chen & Shibata based on numerical simulations. We present a parametric survey of the triggering agent: its polarity orientation, position, and the amount of the unsigned flux. The results suggest that whether a CME can be triggered depends on both the amount and location of the emerging flux, in addition to its polarity orientation. A diagram is presented to show the eruption and non-eruption regimes in the parameter space. The work is aimed at providing useful information for the space weather forecast. 展开更多
关键词 SUN coronal mass ejections (CMEs)-Sun FILAMENTS
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A Possible Explanation of the O'Connell Effect in Close Binary Stars
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作者 Qing-Yao Liu +1 位作者 YU-Lan Yang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2003年第2期142-150,共9页
A theoretical model for explaining the O'Connell effect of close binary stars is given based on the hypothesis that the circumstellar material of a binary system is captured by its components. The results inferred... A theoretical model for explaining the O'Connell effect of close binary stars is given based on the hypothesis that the circumstellar material of a binary system is captured by its components. The results inferred from the model suggest that late-type and/or short-period binaries can easily produce obvious O'Connell effect and that the occurrence of O'Connell effect has no relation with the type of binaries. These conclusions are in agreement with the observed results. The observed O'Connell effects of six binary systems are examined by the model. For three W-subtype W UMa binaries (YY Eri, BX Per and SW Lac), the densities of the materials captured by the two components are assumed to be equal, and the calculated O'Connell effect is found to be almost equal to the observed effect. For three A-subtype W UMa systems (CN And, FG Hya and AU Ser), the two densities are assumed to be different, and are calculated separately. The calculated O'Connell effect turns out to agree better with the observed effect than that was formerly obtained. 展开更多
关键词 binaries: close - star: W UMa - circumstellar matter
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High resolution spectroscopy of two young active late type stars within 20 parsecs of the Sun
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作者 Hui-Juan Wang Jian-Yan Wei 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第3期315-322,共8页
We present high-resolution optical echell spectroscopy of HIP 544 and HIP 46843, two nearby solar like stars. The discovery of these young stars at such a close distance to the Sun is really a surprising phenomenon. I... We present high-resolution optical echell spectroscopy of HIP 544 and HIP 46843, two nearby solar like stars. The discovery of these young stars at such a close distance to the Sun is really a surprising phenomenon. It will help us to have a better understanding of the structure and evolutionary history of the Milky Way. The radial velocities (RV) of HIP 544 and HIP 46843 are measured to be -6.88±0.13km s^-1 and 8.30±0.16km s^-1, respectively, which are more accurate than before. The equivalent widths (EW) of the Li I 6707.8A absorption line of HIP 544 and HIP 46843 are measured to be 110±5 mA and 195±5 mA respectively. Based on these properties, HIP 544 is estimated to be 100-800Myr old and HIP 46843 30-100Myr old using three relatively creditable methods. 展开更多
关键词 STARS late-type - stars individual (HIP544 HIP46843) - stars activity - techniques radial velocities - techniques SPECTROSCOPIC
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Support Vector Machine combined with K-Nearest Neighbors for Solar Flare Forecasting 被引量:10
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作者 Rong Li Hua-Ning Wang Han He Yan-Mei Cui Zhan-Le Du 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第3期441-447,共7页
A method combining the support vector machine (SVM) the K-Nearest Neighbors (KNN), labelled the SVM-KNN method, is used to construct a solar flare forecasting model. Based on a proven relationship between SVM and ... A method combining the support vector machine (SVM) the K-Nearest Neighbors (KNN), labelled the SVM-KNN method, is used to construct a solar flare forecasting model. Based on a proven relationship between SVM and KNN, the SVM-KNN method improves the SVM algorithm of classification by taking advantage of the KNN algorithm according to the distribution of test samples in a feature space. In our flare forecast study, sunspots and 10cm radio flux data observed during Solar Cycle 23 are taken as predictors, and whether an M class flare will occur for each active region within two days will be predicted. The SVM- KNN method is compared with the SVM and Neural networks-based method. The test results indicate that the rate of correct predictions from the SVM-KNN method is higher than that from the other two methods. This method shows promise as a practicable future forecasting model. 展开更多
关键词 SUN flare - Sun sunspot - Sun activity - Sun magnetic fields
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A Study of the Molecular Cloud S64 with Multiple Lines of CO Isotopes
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作者 Lei Zhu Yue-Fang Wu Yue Wei 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2006年第1期61-68,共8页
We report on a study of the molecular cloud S64 with observations at millimeter wavelengths of multiple molecular lines of CO isotopes. A weak outflow is found, and its physical parameters are estimated. The departure... We report on a study of the molecular cloud S64 with observations at millimeter wavelengths of multiple molecular lines of CO isotopes. A weak outflow is found, and its physical parameters are estimated. The departure of the core of S64 from the S64 HII region indicates that there are still other star formation activities in that region. 展开更多
关键词 stars: formation -- ISM: clouds -- ISM: individual: S64 -- ISM: jets and outflows -- ISM: evolution -- ISM: kinematics and dynamics
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Radio Identifications of Markarian Galaxies and the Correlation between Radio and Far-Infrared Properties
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作者 Shao-Guang Luo Xue-Bing Wu 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2005年第5期448-456,共9页
By checking DSS optical images and NVSS radio images, 782 Markarian galaxies were identified to be NVSS radio sources. A comparison of the radio luminosity at 1.4GHz and the far-infrared (FIR) luminosity for 468 “n... By checking DSS optical images and NVSS radio images, 782 Markarian galaxies were identified to be NVSS radio sources. A comparison of the radio luminosity at 1.4GHz and the far-infrared (FIR) luminosity for 468 “normal” galaxies shows a tight correlation. Most of the Seyfert galaxies and quasars follow the radio-FIR relation deduced from the “normal” galaxy sample, but with a somewhat larger scatter. A total 167 Markarian galaxies, comprising 100 “normal” galaxies, 66 Seyfert galaxies and one quasar, have either excess radio emission or much lower FIR spectral index α(25 μm, 60 μm). These galaxies may be classified as “AGN-powered”. For “normal” galaxies, the average q value (defined as the log ratio between FIR and radio luminosities) is 2.3. There seems a trend for q to slightly decrease with increasing radio luminosity. This may imply that the ongoing active star formation in galaxies with higher radio luminosities is more efficient in heating the cosmic-ray electrons. 展开更多
关键词 galaxies: active - galaxies: Seyfert - galaxies: starburst - radio continuum: galaxies - infrared: galaxies
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Autoregressive Spectral Estimation for Quasi-Periodic Oscillations
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作者 Li Chen Ti-Pei Li 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2005年第5期495-507,共13页
Modern methods of spectral estimation based on parametric time-series models are useful tools in power spectral analysis. We apply the autoregressive (AR) model to study quasi-periodic oscillations (QPOs). An empi... Modern methods of spectral estimation based on parametric time-series models are useful tools in power spectral analysis. We apply the autoregressive (AR) model to study quasi-periodic oscillations (QPOs). An empirical formula to estimate the expectation and standard deviation of the noise AR power densities is derived, which can be used to estimate the statistical significance of an apparent QPO peak in an AR spectrum. An iterative adding-noise algorithm in AR spectral analysis is proposed and applied to studying QPOs in the X-ray binary Cir X-1. 展开更多
关键词 methods: data analysis - stars: individual (Circinus X-1) - X-rays:stars
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A Study on the Paul-Baker System as an Instrument for Multi-object Spectrum Observation
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作者 Xiang-Yan Yuan Ding-Qiang Su +1 位作者 Xiang-Qun Cui Gen-Rong Liu 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2005年第5期546-556,共11页
Paul-Baker systems with 4° flat field and 5° fiat field are studied. Their light obstructions under different f/ratios of the primary mirror are analyzed. Due to the strong f/ratio of the system, a focal len... Paul-Baker systems with 4° flat field and 5° fiat field are studied. Their light obstructions under different f/ratios of the primary mirror are analyzed. Due to the strong f/ratio of the system, a focal length extender is designed in order to match the following fiber instrumentation, and two kinds of dispersion prism correctors are designed for correcting the atmospheric dispersion. We compare the designed Paul-Baker system with LAMOST, the national major scientific project now under construction. 展开更多
关键词 techniques: telescopes - instrumentation: miscellaneous
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