The normalized inclination distributions are presented for the spiral galaxies in RC3.The results show that,except for the bin of 81°-90°,in which the apparent minor isophotal diameters that are used to obta...The normalized inclination distributions are presented for the spiral galaxies in RC3.The results show that,except for the bin of 81°-90°,in which the apparent minor isophotal diameters that are used to obtain the inclinations are affected by the central bulges,the distributions for Sa,Sab,Scd and Sd are well consistent with the Monte-Carlo simulation of random inclinations within 3-σ and Sb and Sbc almost,but Sc is different.One reason for the difference between the real distribution and the Monte-Carlo simulation of Sc may be that some quite inclined spirals,the arms of which are inherently loosely wound on the galactic plane and should be classified to Sc galaxies,have been incorrectly classified to the earlier ones,because the tightness of spiral arms which is one of the criteria of the Hubble classification in RC3 is different between on the galactic plane and on the tangent plane of the celestial sphere.Our result also implies that there might exist biases in the luminosity functions of individual Hubble types if spiral galaxies are only classified visually.展开更多
This letter is devoted to the discussion of the Hawking radiation of Dirac particles in 1+1 dimensional space-time.The general nonstatic 1+1 dimensional metric is used to calculate the radiant spectrum and the express...This letter is devoted to the discussion of the Hawking radiation of Dirac particles in 1+1 dimensional space-time.The general nonstatic 1+1 dimensional metric is used to calculate the radiant spectrum and the expression of radiation temperature,which,as an example,verifies the quantum-mechanical instability in black hole due to Hawking radiation.展开更多
基金Supported by both the National Natural Science Foundation of China under Grant 19603003,and K.C.Wong Education Foundation,Hong Kong。
文摘The normalized inclination distributions are presented for the spiral galaxies in RC3.The results show that,except for the bin of 81°-90°,in which the apparent minor isophotal diameters that are used to obtain the inclinations are affected by the central bulges,the distributions for Sa,Sab,Scd and Sd are well consistent with the Monte-Carlo simulation of random inclinations within 3-σ and Sb and Sbc almost,but Sc is different.One reason for the difference between the real distribution and the Monte-Carlo simulation of Sc may be that some quite inclined spirals,the arms of which are inherently loosely wound on the galactic plane and should be classified to Sc galaxies,have been incorrectly classified to the earlier ones,because the tightness of spiral arms which is one of the criteria of the Hubble classification in RC3 is different between on the galactic plane and on the tangent plane of the celestial sphere.Our result also implies that there might exist biases in the luminosity functions of individual Hubble types if spiral galaxies are only classified visually.
基金Supported by the National Natural Science Foundation of China,and the Young Astronomer Laboratory of Shanghai Observatory.
文摘This letter is devoted to the discussion of the Hawking radiation of Dirac particles in 1+1 dimensional space-time.The general nonstatic 1+1 dimensional metric is used to calculate the radiant spectrum and the expression of radiation temperature,which,as an example,verifies the quantum-mechanical instability in black hole due to Hawking radiation.
