BL Lacertae （BL Lac） objects at high redshifts （z ≥ 2） are rarely detected. Through careful analysis of its Sloan Digital Sky Survey spectrum, BZB J1450＋5201 is confirmed to be a high-z BL Lac object with z ≥ 2...BL Lacertae （BL Lac） objects at high redshifts （z ≥ 2） are rarely detected. Through careful analysis of its Sloan Digital Sky Survey spectrum, BZB J1450＋5201 is confirmed to be a high-z BL Lac object with z ≥ 2.471 by identifying the Lyα 1216 and CIV 1548/1550 absorption lines. This indicates that BZB J1450＋5201 is the most distant BL Lac object discovered to date. Careful analysis of the five-year Fermi-LAT data of 2FGL J1451.0＋5159 shows that its γ-ray emission is robust with a confidence level of 6.2σ at 1-3 GeV and 6.7σ at 3-10 GeV. This analysis with the five-year data overcomes confusion with its bright neighbor, which is a problem when analyzing the two-year data. In addition, 2FGL J 1451.0＋5159 is confirmed to be associated with BZB J1450＋5201 using the five-year data. The analysis of multiwavelength data, from radio to γ-ray energies, indicates that BZB J1450＋5201 is an intermediate synchrotron peaked （ISP） source. Its multiwavelength properties are consistent with distributions of other ISP sources at lower redshifts in the second Fermi-LAT AGN catalog. The pure synchrotron self-Compton （SSC） model seems to be disfavored, but the scattering of weak external emission plus the SSC process can provide a satisfactory description of the broadband emission.展开更多
风险投资急诊室如今的风险投资家都在忙着挽救陷于生存危机的新创企业,因此 Softbank Venture Capital 的合伙人据此向自己和风险投资家同行们开了个小小玩笑。10月10日,在旧金山的公司会议室里,合伙人们播放了一部节奏很快、模仿热门...风险投资急诊室如今的风险投资家都在忙着挽救陷于生存危机的新创企业,因此 Softbank Venture Capital 的合伙人据此向自己和风险投资家同行们开了个小小玩笑。10月10日,在旧金山的公司会议室里,合伙人们播放了一部节奏很快、模仿热门电视剧《急诊室》(ER)的自拍录像片。五名软库(Softbank)执行董事一身医生装扮,正在竭尽全力抢救一家濒危的 B2C(企业对消费者)公司。展开更多
With trade of over $100 billion in 2009, the importance of China and Africa bilateral exchanges are growing daily. This blooming relationship increases the need of understanding the ways of doing business.This regular...With trade of over $100 billion in 2009, the importance of China and Africa bilateral exchanges are growing daily. This blooming relationship increases the need of understanding the ways of doing business.This regular column will provide a practical insight of doing business in China, including tips and advice based on experience.展开更多
基金Supported by the National Natural Science Foundation of China
文摘BL Lacertae （BL Lac） objects at high redshifts （z ≥ 2） are rarely detected. Through careful analysis of its Sloan Digital Sky Survey spectrum, BZB J1450＋5201 is confirmed to be a high-z BL Lac object with z ≥ 2.471 by identifying the Lyα 1216 and CIV 1548/1550 absorption lines. This indicates that BZB J1450＋5201 is the most distant BL Lac object discovered to date. Careful analysis of the five-year Fermi-LAT data of 2FGL J1451.0＋5159 shows that its γ-ray emission is robust with a confidence level of 6.2σ at 1-3 GeV and 6.7σ at 3-10 GeV. This analysis with the five-year data overcomes confusion with its bright neighbor, which is a problem when analyzing the two-year data. In addition, 2FGL J 1451.0＋5159 is confirmed to be associated with BZB J1450＋5201 using the five-year data. The analysis of multiwavelength data, from radio to γ-ray energies, indicates that BZB J1450＋5201 is an intermediate synchrotron peaked （ISP） source. Its multiwavelength properties are consistent with distributions of other ISP sources at lower redshifts in the second Fermi-LAT AGN catalog. The pure synchrotron self-Compton （SSC） model seems to be disfavored, but the scattering of weak external emission plus the SSC process can provide a satisfactory description of the broadband emission.
文摘With trade of over $100 billion in 2009, the importance of China and Africa bilateral exchanges are growing daily. This blooming relationship increases the need of understanding the ways of doing business.This regular column will provide a practical insight of doing business in China, including tips and advice based on experience.
