A multiwavelength study of the massive star-forming region IRAS 22506+5944     

Yuan-Wei Wu  Ye Xu  Ji Yang  Jing-Jing Li 《中国天文和天体物理学报》2009,9(12)

  相似文献   

The tidal tails of globular cluster Palomar 5 based on the neural networks method     

Hu Zou  Zhen-Yu WU  Jun Ma  Xu Zhou 《中国天文和天体物理学报》2009,9(10)

  相似文献   

An unusual timing and spectral state of a black hole microquasar XTE J1550-564     

Ying-Kang Jin Shuang-Nan Zhang Ti-Pei Li 《中国天文和天体物理学报》2009,9(2)

An unusual timing and spectral state of a black hole microquasar XTE J1550-564 observed with RXTE is analyzed. Millisecond variabilities are found, which are significantly shorter than the minimum possible time scale in the light curves of black hole binaries, as suggested by Sunyaev & Revnivtsev (2000). The X-ray spectral fitting result indicates that there is an unusual soft component in the spectrum, which may be responsible for the millisecond variabilities. The millisecond variabilities as well as the unusual soft spectral component should be produced from some small, but independent active regions in the accretion disk.  相似文献   

The pairwise velocity difference of over 2000 BHB stars in the Milky Way halo     

Xiang-Xiang Xue  Hans-Walter Rixm  Gang Zhao 《中国天文和天体物理学报》2009,9(11)

  相似文献   

Studying the Fermi GeV light curve of Vela with the two-pole caustic model     

Huan Yu  Jun Fang  Ze-Jun Jiang 《中国天文和天体物理学报》2009,9(12)

  相似文献   

A truncated accretion disk in the galactic black hole candidate source H1743-322     

Kandulapati Sriram  Vivek Kumar Agrawal  Arikkala Raghurama Rao 《中国天文和天体物理学报》2009,9(8)

  相似文献   

A planetary companion orbiting the intermediate-mass G Giant HD 173416     

Yu-Juan Liu Bun＇ei Sato Gang Zhao Hiroyasu Ando 《中国天文和天体物理学报》2009,9(1)

The discovery of a planetary companion to the intermediate-mass late-type giant star HD173416 from precise Doppler surveys of G and K giants at Xingiong station and Okayama Astrophysical Observatory (OAO) is presented in this letter. The planet has a minimum mass of 2.7 MJ an eccentricity of 0.21, a semimajor axis of 1.16 AU and an orbital period of 324 days.  相似文献   

What is the closest black hole to the Sun?     

Cdric Foellmi 《New Astronomy》2009,14(8):674-691

We examine the distance of the two galactic microquasars GRO J1655–40 and A 0620–00 which are potentially the two closest black holes to the Sun. We aim to provide a picture as wide and complete as possible of the problem of measuring the distance of microquasars in our Galaxy. The purpose of this work is to fairly and critically review in great detail every distance method used for these two microquasars in order to show that the distances of probably all microquasars in our Galaxy are much more uncertain than currently admitted. Moreover, we show that many confirmations of quantitative results are often entangled and rely on very uncertain measurements. We also present a new determination of the maximum distance of GRO J1655–40 using red clump giant stars, and show that it confirms our earlier result of a distance less than 2 kpc instead of 3.2 kpc. Because, it then becomes more likely that GRO J1655–40 could originate from the stellar cluster NGC 6242, located at 1.0 kpc, we review the distance estimations of A 0620–00, which is so far the closest black hole with an average distance of about 1.0 kpc. We show that the distance methods used for A 0620–00 are also problematic. Finally, we present a new analysis of spectroscopic and astrometric archival data on this microquasar, and apply the maximum distance method of Foellmi et al. [Foellmi, C., Depagne, E., Dall, T.H., Mirabel, I.F., 2006b. A&A 457, 249]. It appears that A 0620–00 could indeed be even closer to the Sun than currently estimated, and consequently would be the closest known black hole to the Sun.  相似文献   

舟山近海日本囊对虾(Marsupenaeus japonicus)野生群体与露天养殖越冬群体间的形质差异     

富裕  李鸿鹏  任夙艺  王志铮  林祖好 《海洋与湖沼》2016,47(1):91-98

鉴于舟山沿海日本囊对虾秋苗养殖成活率显著低于春季和夏季人工养殖苗种之实际,深入开展适合于本地沿海养殖的日本囊对虾秋苗的优质亲体的选种研究显得十分必要。为此,作者采用聚类分析、主成分分析和判别分析等方法定量研究了舟山近海日本囊对虾野生群体和露天池塘越冬养成群体间的形质特征差异。结果表明:两者在本研究所涉18项形质评价指标中的相似性指数仅为11.11%,欧氏距离为4.243(P0.01);经主成分分析,提取到的5个特征值均大于1的主成分,累计贡献率达85.27%,其中第1主成分为以营养生理状况指数、额剑上缘锯齿数以及腹部肌肉发达程度为主导的体质强壮因子,第2主成分为以寻食视野与胸腔空间大小为主导的捕食运动功能因子,后3个主成分为以尾节肌肉发达程度为主导的避敌运动功能因子;采用逐步判别法,以判别贡献率较大的9项形质评价指标为自变量,所建Fisher分类函数方程组可清晰区分日本囊对虾野生群体和越冬养成群体,其中野生群体的判别准确率P1、P2分别为99.33%和96.13%,越冬养成群体的判别准确率P1、P2分别为96%和99.31%,两者综合判别准确率为97.67%。因此,日本囊对虾秋苗野生亲本形质特征的选择,应以秋苗越冬养成群体为参照。  相似文献   

单窗算法的大气参数估计方法   总被引：95，自引：10，他引：95  

覃志豪  LI Wenjuan  Zhang Minghua  Arnon Karnieli  Pedro Berliner 《国土资源遥感》2003,14(2):37-43

根据地表热辐射传导方程,提出了一个简单可行且精度较高的专门用于从TM6数据中演算地表温度的方法——单窗算法.这一算法把大气和地表状态对地表热传导的影响直接包括在演算公式中.该方法需要两个大气参数进行地表温度的演算,即大气平均作用温度和大气透射率.本文论述这两个大气参数的估计方法:根据大气水分含量或地表附近空气湿度来估计大气透射率;通过分析标准大气剖面资料,尤其是大气水分和气温随高程的变化规律,根据地表温度推算大气平均作用温度.  相似文献