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701.
702.
Ke-Lai Meng Bin Ma Jun Pan Long-Long Feng Purple Mountain Observatory Chinese Academy of Sciences Nanjing China National Astronomical Observatories Beijing 《中国天文和天体物理学报》2011,(6)
Flux-limited and volume-limited galaxy samples are constructed from the Sloan Digital Sky Survey(SDSS)data releases DR4,DR6 and DR7 for statistical analysis.The two-point correlation functionsξ(s),monopole of three-point correlation functionsζ0,projected two-point correlation function wp and pairwise velocity dispersionσ12 are measured to test if galaxy samples are fair for these statistics.We find that with the increment of sky coverage of subsequent data releases in SDSS, ξ(s)of the flux-limited sample is... 相似文献
703.
A vertical current sheet is a crucial element in many flare/coronal mass ejection (CME) models. For the first time, Liu et al. reported a vertical current sheet directly imaged during the flare rising phase with the EUV Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO). As a follow-up study, here we present the comprehensive analysis and detailed physical interpretation of the observation. The current sheet formed due to the gradual rise of a transequatorial loop system. As the l... 相似文献
704.
A computational code is developed to help identify metal absorption linesin high resolution QSO spectra,especially in the Lyα forest.The input to the codeincludes a list of line central wavelengths,column densities and Doppler widths.Thecode then searches for candidate metal absorption systems and assesses the probability that each system could be real.The framework of the strategy we employ isdescribed in detail and we discuss how to estimate the errors in line profile fitting thatare essential to identifi... 相似文献
705.
Jun-Hui Fan Jun Tao Bo-Chen Qian Yi Liu Jiang-He Yang Fei-Peng Pi Wei Xu Center for Astrophysics Guangzhou University Guangzhou China Astronomy Science Technology Research Laboratory of 《中国天文和天体物理学报》2011,(11)
S5 0716+714 is one of the targets in our long term blazar monitoring program carried out with the 1.56-m telescope at Sheshan Station of Shanghai Astronomical Observatory,China.We report a very rapid variability of ΔI = 0.611 ± 0.102 mag over 3.6 min detected in our monitoring program during the period from December 2000 to March 2007.The rapid variability suggests that the mass for the central black hole is log(M/M) = 7.68 8.38. 相似文献
706.
Li-Yan Zhang Yong-Liao Zou Jian-Zhong Liu Jian-Jun Liu Ji Shen Ling-Li Mu Xin Ren Wei-Bin Wen Chun-Lai Li National Astronomical Observatories Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2011,(6)
The main goal of the gamma-ray spectrometer(GRS) onboard Chang'E1(CE-1) is to acquire global maps of elemental abundances and their distributions on the moon,since such maps will significantly improve our understanding of lunar formation and evolution.To derive the elemental maps and enable research on lunar formation and evolution,raw data that are received directly from the spacecraft must be converted into time series corrected gamma-ray spectra.The data correction procedures for the CE-1 GRS time series... 相似文献
707.
708.
We examine the solar cycle distribution of major geomagnetic storms (Dst ≤ -100 nT), including intense storms at the level of- 200 nT< Dst ≤-100 nT, great storms at -300 nT< Dst ≤-200 nT, and super storms at Dst ≤-300 nT, which occurred during the period of 1957-2006, based on Dst indices and smoothed monthly sunspot numbers. Statistics show that the majority (82%) of the geomagnetic storms at the level of Dst ≤-100 nT that occurred in the study period were intense geomagnetic storms, with 12.4% ranked as great storms and 5.6% as super storms. It is interesting to note that about 27% of the geomagnetic storms that occurred at all three intensity levels appeared in the ascending phase of a solar cycle, and about 73% in the descending one. Statistics also show that 76.9% of the intense storms, 79.6% of the great storms and 90.9% of the super storms occurred during the two years before a solar cycle reached its peak, or in the three years after it. The correlation between the size of a solar cycle and the percentage of major storms that occurred, during the period from two years prior to maximum to three years after it, is investigated. Finally, the properties of the multi-peak distribution for major geomagnetic storms in each solar cycle is investigated. 相似文献
709.
Yi-Nan Zhu Hong Wu Hai-Ning Li Chen Cao National Astronomical Observatories Chinese Academy of Sciences Beijing China of Sciences China Graduate University of Chinese Academy of Sciences Beijing China Institute of Space Science Physics Sh ong University at Weihai Sh ong 《中国天文和天体物理学报》2010,10(4)
We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey.We derived the formulae to calculate the stellar mass by using IRAC 3.6 μm and 4.5 μm luminosities.The massto-luminosity ratios of IRAC 3.6 μm and 4.5 μm luminosities are more sensitive to the star formation history of galaxies than to other factors,such as the intrinsic extinction,metallicity and star formation rate.To remove the effect of star formation history,we used g-r color to recalibrate the formulae and obtain a better result.Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae.Due to the emission from dust heated by the hottest young stars,luminous infrared galaxies present higher IRAC 4.5 μm luminosities compared to IRAC 3.6 μm luminosities.For most of type-Ⅱ AGNs,the nuclear activity cannot enhance 3.6 μm and 4.5 μm luminosities compared with normal galaxies.Star formation in our AGNhosting galaxies is also very weak,almost all of which are early-type galaxies. 相似文献
710.
Xu Zhou Zhen-Yu Wu Zhao-Ji Jiang Xiang-Qun Cui Long-Long Feng Xue-Fei Gong Jing-Yao Hu Qi-Sheng Li Gen-Rong Liu Jun Ma Jia-Li Wang Li-Fan Wang Jiang-Hua Wu Li-Rong Xia Jun Yan Xiang-Yan Yuan Feng-Xiang Zhai Ru Zhang Zhen-Xi Zhu National Astronomical Observatories Chinese Academy of Sciences Beijing China Nanjing Institute of Astronomical Optics & Technology National Astronomical Observatories Nanjing China Purple Mo... 《中国天文和天体物理学报》2010,10(3)