Shock oscillation model for quasi-periodic oscillations in stellar mass and supermassive black holes

We numerically examine centrifugally supported shock waves in 2D rotating accretion flows around a stellar mass  (10 M_⊙)  and a supermassive  (10⁶ M_⊙)  black holes over a wide range of input accretion rates of     . The resultant 2D shocks are unstable with time and the luminosities show quasi-periodic oscillations (QPOs) with modulations of a factor of 2–3 and with periods of a tenth of a second to several hours, depending on the black hole masses. The shock oscillation model may explain the intermediate frequency QPOs with 1–10 Hz observed in the stellar mass black hole candidates and also suggest the existence of QPOs with the period of hours in active galactic nuclei. When the accretion rate     is low, the luminosity increases in proportion to the accretion rate. However, when     greatly exceeds the Eddington critical rate     , the luminosity is insensitive to the accretion rate and is kept constantly around  ∼3 L _E  . On the other hand, the mass-outflow rate     increases in proportion to     and it amounts to about a few per cent of the input mass-flow rate.     

黑洞吸积理论及其天体物理学应用的近期发展(Ⅱ)

黑洞吸积理论是天体物理学的一个基础理论,是认识许多高能天体系统如活动星系核、黑洞X射线双星,以及伽马暴等的重要物理基础.该文评述近年来黑洞吸积理论尤其是径移主导吸积流模型(advection-dominated accretion flow)及其变种的主要发展,并介绍该理论在银河系中心、低光度活动星系核、黑洞X射线双星等方面的应用.共分为两篇,该文是第2篇,内容是关于黑洞热吸积流理论在低光度活动星系核以及黑洞X射线双星方面的应用.     

Iron line profiles and self-shadowing from relativistic thick accretion discs

We present Fe Kα line profiles from and images of relativistic discs with finite thickness around a rotating black hole using a novel code. The line is thought to be produced by iron fluorescence of a relatively cold X-ray-illuminated material in the innermost parts of the accretion disc and provides an excellent diagnostic of accretion flows in the vicinity of black holes. Previous studies have concentrated on the case of a thin, Keplerian accretion disc. This disc must become thicker and sub-Keplerian with increasing accretion rates. These can affect the line profiles and in turn can influence the estimation of the accretion disc and black hole parameters from the observed line profiles. We here embark on, for the first time, a fully relativistic computation which offers key insights into the effects of geometrical thickness and the sub-Keplerian orbital velocity on the line profiles. We include all relativistic effects such as frame-dragging, Doppler boost, time dilation, gravitational redshift and light bending. We find that the separation and the relative height between the blue and red peaks of the line profile diminish as the thickness of the disc increases. This code is also well suited to produce accretion disc images. We calculate the redshift and flux images of the accretion disc and find that the observed image of the disc strongly depends on the inclination angle. The self-shadowing effect appears remarkable for a high inclination angle, and leads to the black hole shadow being in this case, completely hidden by the disc itself.     

黄鳍东方鲀人工育苗技术及胚胎、仔稚幼鱼发育特征研究

为开展黄鳍东方鲀(Fugu xanthopterus)批量全人工育苗、胚胎及仔稚幼鱼发育特征研究, 作者使用地欧酮(DOM)、促黄体释放激素类似物(LRH)及绒毛膜促性腺激素(HCG)对性成熟黄鳍东方鲀进行人工催产。结果表明黄鳍东方鲀亲鱼效应时间为39～60h, 获产率为55.0%～92.5%; 卵受精率为35.5%～84.7%, 3 年产卵7 400 g; 受精卵在海水水温17.0～23.2℃、盐度21～30、pH8.0～8.2 人工条件下孵化, 孵化率为33.6%～91.7%, 孵出仔鱼499 万尾; 2005 年、2006 年经前期培育, 共培育出黄鳍东方鲀后期仔鱼394.5 万尾, 成活率为68.2%～94.3%; 室内水泥池后期培育出平均全长2.6 cm±0.2 cm 幼鱼3100 尾, 成活率为15.5%; 池塘生态培育出平均全长3.7 cm±0.5 cm 幼鱼53.3 万尾, 成活率为11.2%～13.8%。黄鳍东方鲀受精卵为沉性黏性卵, 近椭球形, 乳白色, 卵膜厚且不透明, 卵径0.9～1.0mm,在海水水温18.2～22.2℃条件下, 3 h 分裂为2 细胞; 3 h 20 min 4 细胞; 3 h 45 min 8 细胞; 10 h 10 min 多细胞; 17 h 30 min 囊胚出现; 28 h 原肠期; 57 h 15 min 胚体形成期; 69 h 20 min 心跳出现; 130 h 50 min出膜期; 144 h 孵出仔鱼。初孵仔鱼全长2.2～2.4 mm, 体圆而粗短, 尾部细长、透明; 孵出后第20 天, 胸鳍、臀鳍、背鳍基本形成, 进入稚鱼期; 孵出后第45 天, 上下颌门齿发达, 各鳍发育完整, 小刺基本形成, 进入幼鱼期。     

Primordial black holes

Primordial black holes (PBHs) are a profound signature of primordial cos-mological structures and provide a theoretical tool to study nontrivial physics of the early Universe. The mechanisms of PBH formation are discussed and observational constraints on the PBH spectrum, or effects of PBH evaporation, are shown to re-strict a wide range of particle physics models, predicting an enhancement of the ul-traviolet part of the spectrum of density perturbations, early dust-like stages, first or-der phase transitions and stages of superheavy metastable particle dominance in the early Universe. The mechanism of closed wall contraction can lead, in the inflation-ary Universe, to a new approach to galaxy formation, involving primordial clouds of massive BHs created around the intermediate mass or supermassive BH and playing the role of galactic seeds.     

Spawning of the frostfish,Lepidopus caudatus (Pisces: Trichiuridae), in New Zealand waters

Frostfish spawning, as indicated by the presence of planktonic eggs, was observed mainly in north‐eastern, but also in south‐western, New Zealand waters in spring to autumn. Spawning takes place in the afternoon in outer shelf waters 50–200 m deep, with surface temperatures and salinities between 17.5 and 22.0°C and 35.3 and 35.6‰ respectively. Egg and oil droplet diameters ranged from 1.65 to 1.75 mm and 0.40 to 0.43 mm respectively.