黑洞吸积盘的数值模拟     

部德福 《天文学进展》2011,(1):117-119

近十几年来,人们已经对吸积盘进行了深入的研究。前人很多工作都是解析工作。虽然解析工作能够简单明了地揭示盘的许多重要性质,但吸积盘的很多重要性质(例如:对流和外流)没有办法通过解析工作进行深入的研究。数值模拟是研究天体物理的重要手段。近十年来,随着计算机技术的迅速发展,数值模拟在天体物理研究中扮演了越来越重要的角色。本论文主要用数值模拟的手段研究吸积盘中一些重要的物理过程。  相似文献   

The Relation between the Inclinations of Broad Line Regions and the Accretion Disk     

Wei-Hao BianNational Astronomical Observatories  Chinese Academy of Sciences  Beijing Department of Physics  Nanjing Normal University  Nanjing   《中国天文和天体物理学报》2005,5(1):21-26

According to the standard model, an active galactic nucleus (AGN) consists of an inner accretion disk with a jet around a central massive black hole, and a number of outer broad line regions (BLRs) and narrow line regions (NLRs). The geometrical relationship between the BLRs and the accretion disk is not well understood. Assuming the motion of the BLRs is virialized and its configuration is disk-like, we derived its inclination to the line of sight for a sample of AGNs from their bulge stellar velocity dispersion, their size of the BLRs and their Hβ linewidth. Compared with the inclination of the accretion disk obtained from the X-ray Fe Kα emission lines, we found that there is no positive correlation between the two. Our results showed that BLRs are not coplanar with the accretion disk and that we should be cautious of using the BLRs inclination as the disk inclination. The non-coplanar geometry of the outer BLRs and the inner accretion disk provides clues to the origin of BLRs and the properties of the accretion disk. Our preferable interpretation is that BLRs arise out of the outer part of a warped accretion disk.  相似文献   

First MERLIN Observations of Line Emission from the OH Megamaser toward IRAS 10173＋0828     

Zhi-Yao Yu Shanghai Astronomical Observatory  Chinese Academy of Sciences  Shanghai National Astronomical Observatories  Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2005,5(2):159-164

Many galaxies are thought to contain massive black holes, with masses in excess of ten million solar masses, at their centres and warped circumnu-clear toruses. The best evidence comes from observing gas or masers rotating rapidly within a circumnuclear torus surrounding a central body. Here we report on the first MERLIN observations of line emission from the OH megamaser toward IRAS 10173+0828. The position of peak flux contours of the OH megamaser is consistent with that of the continuum in IRAS 10173+0828. This means that the OH megamaser is a diffuse unsaturated maser which could amplify the diffuse 18 cm continuum emission with an amplification factor of order unity.  相似文献   

X-ray Emission Lines in GRB Afterglows： Evidence for a Two-component Jet Model     

Wei-Hong Gao  Da-Ming Wei Purple Mountain Observatory  Chinese Academy of Sciences  Nanjing National Astronomical Observatories  Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2005,5(6):571-578

X-ray emission lines have been observed in X-ray afterglows of several γ-ray bursts (GRBs). It is a major breakthrough for understanding the nature of the progenitors. It has been proposed that the X-ray emission lines can be well explained by the Geometry-Dominated models, but in these models the illuminating angle is much larger than that of the collimated jet of the GRB. For GRB 011211, we have obtained an illuminating angle of about θ- 45°, while the angle of the GRB jet is only 3.6°. So we propose that the outflow of GRBs with emission lines should have two distinct components: a wide component that illuminates the reprocessing material and produces the emission lines and a narrow one that produces the GRB. Observations show the energy for producing the emission lines is higher than that of the GRB. In this case, when the wide component dominates the afterglows, a bump should appear in the GRB afterglow. For GRB 011211, the bump should occur within 0.05 days of the GRB, which is obviously too early for the observation to catch it. Alongside the X-ray emission lines there should also be a bright emission component between the UV and the soft X-rays. These features can be tested by the Swift satellite in the near future.  相似文献   

De Sitter背景时空中NUT-Kerr-Newman黑洞的玻色子熵   总被引：1，自引：0，他引：1  

葛先辉  沈有根 《天文学报》2003,44(1):80-86

众所周知，一般黑洞的欧拉示性数都为2(或者为0)，而NUT—Kerr—Newman黑洞是个例外，其欧拉示性数大于2.因此计算NUT—Kerr—Newman黑洞的玻色子熵有特殊的意义．运用在brick-wall方法的基础上发展起来的膜模型计算了NUT-Kerr—Newman黑洞在de Sitter时空背景下的玻色子熵．结果表明，在选取适当的截断因子的情况下，该黑洞的熵仍满足Bekenstein—Hawking面积定律．  相似文献   

缘于任意自旋场的Vaidya黑洞的熵(英文)     

SHEN Yougen GAO Changjun 《中国科学院上海天文台年刊》2003,(1)

用在brick模型基础上发展起来的membrane模型 ,计算了缘于任意自旋场的非静态黑洞———Vaidya黑洞的自由能和熵。结果表明 ,玻色子场 (自旋s =1,2 )和费米子场 (自旋s =1/2 )的熵都恰好与黑洞的视界面积成正比 ,这与静态和稳态的情况相同。而且 ,玻色子和费米子场的熵具有相同的形式 ,二者相差一个系数  相似文献   

The Optical Variability of 3C 273     

《中国天文和天体物理学报》2001,1(3):245-249

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On the Black Hole - Bulge Mass Ratios in Narrow-Line Seyfert 1 Galaxies     

Wei-Hao Bian  Yong-Heng Zhao National Astronomical Observatories  Chinese Academy of Sciences  Beijing Department of Physics  Nanjing Normal University  Nanjing 《中国天文和天体物理学报》2003,3(2):119-124

We present estimated ratios of the central black hole mass to the bulge mass (Mbh/Mbulge) for 15 Narrow Line Seyfert 1 galaxies (NLS1s). It is found that NLS1s apparently have lower mass ratios: the average mass ratio is about 1 × 10-4 with a spread of 2, which is one order of magnitude lower than for Broad Line AGNs and quiescent galaxies. This lower value, as compared to that established essentially for all other types of galaxies, can be accounted for by an underestimation of the black hole masses and an overestimation of the bulge masses in the NLS1s.  相似文献   

活动星系核的铁Kα和铁Kβ发射线-Cerenkov线状辐射的进一步证据     

刘当波  陈磊  陈文屏  尤峻汉 《天文学报》2006,47(1):31-36

最近XMM—Newton观测到了Seyfert 1星系,NGC3783,除存在着6．4keV的铁Kα发射线外,还存在着很强的7．0 keV的铁Kβ发射线,且两者之间的等值宽度(EW) 之比难以由传统的“光电吸收-莹光机制”来解释．利用尤峻汉等人提出的Cerenkov线状发射机制可合理解释EWKα／EWKβ．给出了详细的模型考虑和理论计算,结果表明活动星系核中产生铁K线的机制不只有莹光机制还有Cerenkov线状辐射机制．两者共存于活动星系核(AGNs)中,而且以Cerenkov辐射机制为主．  相似文献   

空间激光干涉引力波探测与早期宇宙结构形成     

龚雪飞  徐生年  袁业飞  白姗  边星  曹周键  陈葛锐  董鹏  高天舒  高伟  黄双林  李玉龙  刘影  罗子人  邵明学  孙宝三  唐文林  于品  徐鹏  臧云龙  张海鹏  刘润球 《天文学进展》2015,(1):59-83

空间引力波探测是研究宇宙早期恒星演化和星系形成、黑洞和星系的共同成长等天文学和宇宙学重大问题的一条重要可能途径。经过两期科学院先导科技专项空间科学预研究课题的开展,通过权衡技术的可行性与科学的前瞻性,选择以高红移开始的中至大质量双黑洞并合系统、星团等稠密动力学环境中涉及中等质量黑洞的双黑洞引力波波源为主要科学目标,给出了我国毫赫兹至赫兹频段空间引力波探测任务计划的初步设计。以该任务设计建议为依据,简要介绍空间引力波探测及其作为一种新的天文观测手段的科学内涵,以及我国空间引力波探测任务设计的科学目标和探测潜力。  相似文献