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951.
Xue-Juan Yang Fang-Jun Lu Bernd Aschenbach Li Chen Faculty of Materials Optoelectronics Physics Xiangtan University Xiangtan China Particle Astrophysics Center Institute of High Energy Physics Chinese Academy of Sciences Beijing China Max-Planck-Institut fu¨r Extraterrestrische Physik Garching Germany Department of Astronomy Beijing Normal University Beijing China 《中国天文和天体物理学报》2011,11(4)
We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary.The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star.The XMM-Newton European Photon Imaging Camera and Reflection Grating Spectrometer spectra of Algol in its quiescent state are described by a two-temperature plasma model.The cool component has a temperature around 6.4×106 K while that of the hot component... 相似文献
952.
The ability to predict the future behavior of solar activity has become extremely import due to its effect on the environment near the Earth.Predictions of both the amplitude and timing of the next solar cycle will assist in estimating the various consequences of space weather.The level of solar activity is usually expressed by international sunspot number (Rz).Several prediction techniques have been applied and have achieved varying degrees of success in the domain of solar activity prediction.We predict a... 相似文献
953.
Based on a high resolution and high signal-to-noise ratio(S/N) spectral analysis of 90 solar-type stars,we have established several new metallicity calibrations in the Teff range [5600,6500]K based on red spectra with the wavelength range of 560-880nm.The new metallicity calibrations are applied to determine the metallicity of solar analogs selected from Sloan Digital Sky Survey(SDSS) spectra.There is a good consistent result with the adopted value presented in SDSS-DR7 and a small scatter of 0.26dex for st... 相似文献
954.
We present here results from our search for X-ray pulsations of the neutron star in the low mass X-ray binary EXO 0748-676 at a frequency near the burstoscillation frequency of 44.7Hz.Using the observations made with the Proportional Counter Array onboard the Rossi X-ray Timing Explorer,we did not find any pulsations in the frequency band of 44.4Hz to 45.0Hz and obtained a 3σ upper limit of 0.47% on the pulsed fraction for any possible underlying pulsation in this frequency band.We also discuss the importan... 相似文献
955.
Jarken Esimbek 《中国天文和天体物理学报》2011,(2)
We report results of the H2CO and H110α survey toward 281 UCHII regions using the Urumqi 25m radio telescope.We obtained 37 new H2CO detections,and H110α was simultaneously detected in eight of them.Only H110α was detected in another UCHII region.We calculated kinematic distances of nine UCHII regions with the detected H110α and resolved the kinematic distance ambiguity for six of them.The detection rate of H2CO of our observation was 13.2%,which is low compared with one of the other authors.The possible re... 相似文献
956.
Galaxy clusters present unique advantages for cosmological study.Here we collect a new sample of 10 lensing galaxy clusters with X-ray observations to constrain cosmological parameters.The redshifts of the lensing clusters lie between 0.1 and 0.6,and the redshift range of their arcs is from 0.4 to 4.9.These clusters are selected carefully from strong gravitational lensing systems which have both X-ray satellite observations and optical giant luminous arcs with known redshifts.Giant arcs usually appear in th... 相似文献
957.
Xiang-Yun Fu Pu-Xun Wu Hong-Wei Yu Zheng-Xiang Li Institute of Physics Hunan University of Science Technology Xiangtan China Center for Nonlinear Science 《中国天文和天体物理学报》2011,(8)
We test the distance-duality(DD) relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al.(the elliptical β model) and Bonamente et al.(the spherical β model),and the luminosity distance DL from Constitution and Union2 type Ia supernova(SNe Ia) datasets. To obtain DL associated with the observed DA at the same redshift,we smooth the noise of the SNe Ia in a model-independent way,obtain the evolutionary curve of DL and,finally,test the DD rel... 相似文献
958.
Xiao-Yan Gao Jian-Cheng Wang Ming Zhou National Astronomical Observatories /Yunnan Observatories Chinese Academy of Sciences Kunming China Key Laboratory for the Structure Evolution of Celestial Objects China Graduate University of Chinese Academy of Sciences Beijing China 《中国天文和天体物理学报》2011,(8)
The external Compton(EC) model is used to study the high energy emission of some blazars,in which the external photon field is considered to dominate inverse Compton radiation. We explore the properties of the external photon field through analyzing the FERMI LAT bright AGN sample within three months of the start of operations in sky-survey mode. In the sample,assuming the high energy radiation of low synchrotron peaked blazars is from the EC process,we find that the external photon parameter Uext/νext may ... 相似文献
959.
Shi-Bi Pu Zhan-Wen Han National Astronomical Observatory /Yunnan Observatory Chinese Academy of Sciences Kunming China Graduate University of Chinese Academy of Sciences Beijing China Key Laboratory of the Structure Evolution of Celestial Objects China 《中国天文和天体物理学报》2011,(8)
We present high quality long slit spectra along the major and minor axes out to 1.5 effective radii of the massive galaxy NGC 4636 taken by the Hobby-Eberly Telescope. Using the Fourier Correlation Quotient method,we measured the stellar line-of-sight velocity distribution along the axes. Furthermore,six Lick/IDS indices(Hβ,Mgb,Fe5015,Fe5270,Fe5335,Fe5406) are derived from the clean spectrum. By comparing the measured absorption line strengths with the predictions of Simple Stellar Population(SSP) models,we... 相似文献
960.
Xiang-Cun Meng Wu-Ming Yang School of Physics Chemistry Henan Polytechnic University Jiaozuo China 《中国天文和天体物理学报》2011,(8)
In the single degenerate(SD) scenario for type Ia supernovae(SNe Ia) ,a mass-accreting white dwarf is expected to experience a supersoft X-ray source(SSS) phase. However,some recent observations showed that the expected number of massaccreting WDs is much lower than that predicted from theory,regardless of whether they are in spiral or elliptical galaxies. In this paper,we performed a binary population synthesis study on the relative duration of the SSS phase to their whole massincreasing phase of WDs leadi... 相似文献