马卡良335的微光变观测

介绍了马卡良335分别发生于1998年和1999年的两次短时标光变。其中的一次是微光变，发生于1999年11月20日，微光变区域的大小约0．807光时。还对微光变的可能机制进行了讨论。     

耀变体光学波段的微光变及能谱变化

耀变体在多个波段的微光变和能谱变化多年来是中外天文观测研究的热点课题.耀变体的微光变于20世纪60年代被发现,20世纪80年代以来发现很多源的微光变具有不同的特性,目前对其物理机制的认识和理论、模型的研究还处于发展阶段.该文总结了7个目前观测最多的耀变体(3C 66A,3C 279,3C 454.3,AO 0235+164,BL Lac,OJ 287,S5 0716+714)在光学波段的微光变和能谱变化的观测历史和最新进展,并对其理论模型作了简单介绍.     

中秋夜观月全食

中秋夜观月全食▲１９９７年９月１７日凌晨发生了本世纪的最后一次中秋夜月全食。本世纪在农历八月十五发生的月食共有１５次，但１３次发生在我国的白天，仅２次在中秋之夜：一次是１９７８年，一次就是１９９７年。今年的中秋节，望（月亮最圆的时刻）发生于１７日２时...     

射电脉冲星周期跃变研究的进展

射电脉冲星周期跃变被认为是研究中子星内部结构和状态的极好探针。脉冲星高频巡天发现了一批年青脉冲星,脉冲星周期跃变的观测研究也有了飞快进展。至少发现了２５颗有跃变现象的脉冲星（简称跃变脉冲星）和７６次跃变事件。ＰＳＲＪ０８３５－４５１０是目前已有跃变脉冲星活动参数最高的,ＰＳＲＪ１３４１－６２２２０的跃变活动最频繁,而ＰＳＲＪ１６１４－５０４７在１９９５年发生的跃变是规模最大的,不同脉冲星的跃变事件     

G.国际原子时和本地原子时之差

UTC(BIPM)一UTC(k)1999年2月5日 叫D 51214 实验室(牌) CSAO一0 .041 JATC一0.277 10日 51219 (娜)一0 .030一0 .281 巧日 51224 (片)一0 .037一0 .300 20日 51229 (那)一0 .041一0 .324 25日 51234 (娜)一0 .039一0 .338TAI一TA(k)1999年2月5日 叨D 51214 实验室(娜) C别心一0.241 JATC 0.792 10日 51219 (那)一0 .234 0 .704 15日 51224 (娜)一0 .242 0 .601 20日 51229 (娜)一0 .252 0 .496 25日 51234 (娜)一0 .253 0 .400—摘自《BIPM CIRCULART)吻.134G.国际原子时和本地原子时之差~~…     

G.国际原子时和本地原子时之差

UTC(BIPM)一UTC(k)1999年,月 坷D 实脸宣 Q认O IATC 6日 51304 (”) 0 .018一0.591 11日 513的 (脚) 0.似呜一0 .616 16日 51314 (”) 0.似5一0 .634 21日 51319 (”) 0 .035一0.砧6 26日 513对 (”) 0 .031一0 .681 31日 51329 (件) 0.036一O。和3日299间016筋1乳白0.0. 一TAI一TA(k)1999年5月 叨D 实验宣 Q认O 1八丁C1日51299 6日11日 51304 51309 (”)(娜)一0,289一0 .292一0 .938一1 .03016日51314一0一0一0一1 21日 51319 (间一0 .293一1.刀O肠日513对一1一0 31日 51329 (”)一0.知2一1 .418一一摘自(B口MC压灯印J卫协冷.…     

M4中反常可疑变星的光电观测

ZB44=G512是位于球状星团M4的C-M图上红巨星支顶部的星。在1975年紫台拍的双筒底片上,姚保安发现它有可疑快速变光,后经多次照相观测,不能排除变光的可能性。1980年我们用北台60公分反光望远镜进行光电观测,看来变光确实是存在的。最引人注目的是在λ_e≈6250波长上,它有变幅约0~m.15,准周期约68.5分钟的快速变光。就我们所知,发现红巨星有这样的光变还第一次,如果为进一步的观测所证实,显然对变星理论和天体演化理论都有重要的意义。 另外,对已发表的反常变星ZB38=G30和ZB39=G327也进行了光电观测,看来照相发现的光变属实。 由于光电观测是在大天顶距时进行,从现有径向变星脉动理论看,C-M图上性质很不同的红蓝星却有相似的变光形式是难以理解的,而按现有的文献上的知识,又找不到哪种误差可以完全解释观测到的准周期光变。所以我们重复文献[7]说过的话,除非发现了新的误差来源,否则我们不得不得出结论:M4方向存在着一群反常变星。 迫切需要进一步的观测来证实这一结论。     

国际原子时和本地原子时之差

UTC《B IPM)一UTC(k)1999年l月 加IJD 实验室 (:SA(〕 JATC 1日 21179 (娜)一0 .026一0 .186 6日 21184 (畔)一0,039一0 .211 11日 21189 (胖)一0 .045一0 .231 16日 21194 (娜)一0,024一0 .220 21日 21199 (娜)一0 .046一0 .239 26日 21204 (娜)一0 .035一0 .245 31日 21209 (娜)一0 .0呜7~0 .262TAI一TA(k)1999年1月 叫D 实验室 e认0 JATC l日 21179 (娜)一0 .172 1 .480 6日 21184 (牌)一0 .198 1 .370 11日 21189 (卢)一0 .209 1 .266 16日 21194 (娜)一0,194 1 .192 21日 21199 (片)一0 .223 1 .081 26日 21204 (娜)一0 .2…     

G.国际原子时和本地原子时之差

UTC(BIPM)一UTC(k)1999年3月 MJD 实验室 CSAO JATC 2日 51239 (拌s)一0。022一0 .342 7日 51244 (拌s)一0,018一0。375 12日 5 1249 (卜s)一0.022一0.397 17日 5 1254 (拼s)一0。021一0.4 19 22日 5 1259 (拼s)一0.020一0.439 27日 5 1264 (拌s)一0 .010一0.443TAI一TA(k)1999年3月 MJD 实验室 CSAO JATC 2日 5 1239 (拌s)一0.241 0。316 7日 51244 (拌s)一0.249 0.219 12日 51249 (拜s)一0.255 0。1 16 17日 5 1254 (拌s)一0 .262 0.017 22日 51259 (拼s)一0.265一0.081 27日 51264 (朴s)一0.258一0.171—摘自《BIPM CI…     

21厘米太阳爆发10毫秒无间隙快速记录观测

本文介绍在国内首次获得了1986年7月12、13日两个爆发事件的太阳10ms连续无间隙快速记录观测资料。这些资料完整地不间断地显示了太阳在两次事件中10ms级快速爆发的全过程。从中可发现太阳10ms级快速活动至少包括:脉冲型,毛刺型,缓变型,缓变脉冲型,缓变毛刺型等非常丰富的内容。     

Microvariability and fast variability of stars. I. standard stars

This is a study of observations of the photometric quantities Vt and Bt, reported in the Hipparcos catalog, for 15 standard stars in order to search for microvariability and rapid variability in their emission. The microvariability is found to be characterized mainly by smooth fluctuations in the brightness. Changes in the magnitudes of the stars HD 28355 and HD 130109 with a period of ~150 min and an amplitude <0^m.02 appear to be caused by vertical shifts in their photospheres. Changes in the magnitudes with an amplitude of ~0^m.01 and a period of 11.4^d in the star e Eri were related to the rotation of spots. A similar microvariability period and amplitude in the star 51 Peg most likely originates in the influence of a planet.     

Intranight optical variability in Seyfert 2 galaxies

Preliminary results from a pilot program to monitor the intranightoptical variability in Seyfert 2 galaxies are reported. This program is designed to test some of the prominent theoretical mechanismsproposed for the origin of optical microvariability in active galacticnuclei (AGN). Two out of 3 Seyfert 2 galaxies observed show evidence formicrovariations. This detection can provide important constraints forthe models utilizing discrete events on accretion disks.     

Optical microvariability of selected PG QSOs

This is a preliminary report of the continuing search for significant optical microvariability in a selected sample of radio-quiet and radio-loud quasi-stellar objects (QSOs). Total of 24 Paloma-Green (PG) quasars are observed. Among them, 17 objects are classified as radio-quiet and seven objects are classified radio-loud. In this classification, the ratio R, radio to optical flux density, is required to be less than 1 in order to assure the objects are reasonably radio-quiet. Two out of 17 radio-quiet QSOs and six out of eight radio-loud QSOs were microvariable. This apparent contrast in microvariations between radio-quiet and radio-loud QSOs does not provide firm support for the theoretical model utilizing discrete events in accretion disks and implies substantial support for models based on propagating shocks on relativistic jets as the likely process responsible for producing most of the microvariations are observed in AGNs.     

Rapid optical variability in radio-quiet QSOs

We report results of the observations at the Vainu Bappu Observatory and the Uttar Pradesh State Observatory of eight radio-quiet quasi-stellar objects (RQQSOs) during 1996–99. This is a part of our ongoing programme to search for intranight optical variability in RQQSOs. Additional evidence for very rapid variability in three of the five optically bright and very luminous RQQSOs we had observed earlier, 1049−006, 1444+408 and 1630+377, was found. Of the three newly observed RQQSOs, the data for 0043+039 are too noisy to allow conclusions about variability to be drawn, but 0748+294 and 0824+098 show strong hints of microvariability. We also present a summary of the results from our entire programme to date, which includes observations of 16 radio-quiet QSOs and one radio-weak QSO, and compare the general properties of rapid variability in radio-quiet versus radio-loud AGN as determined from our work and that of several other groups. Observations of this kind are likely to play a key role in understanding the relative contributions of accretion discs and relativistic plasma jets to rapid optical fluctuations of AGN.     

The Optical Microvariability and Spectral Changes of the BL Lacertae Object S5 0716+714

The BL Lac object S5 0716+714 was monitored in the optical band during October 2008, December 2008 and February 2009. We achieved a best temporal resolution of about 5 min in the BVRI bands. The source was active during the whole monitoring campaign. It showed microvariability in 13 days out of 14 days of observation. Four fast flares were observed with amplitudes ranging from 0.3–0.75 mag. The overall amplitude changes during the whole campaign are ΔB ~ 0. ^m 89, ΔV ~ 0. ^m 80, ΔR ~ 0. ^m 73, and ΔI ~ 0. ^m 51. On internight time scales, strong bluer-when-brighter chromatism was found while different spectral behaviours were found on intranight time scales.     

天体物理非线性问题初探-活动星系核的光变及引力的局部近似

展示活动星系核研究和引力研究中的一些难点,揭示了某些天体的光变存在分形结构的可能性。我们提出了活动星系核的中心黑洞具有某种随机微活动性的假设,该假设可解释活动星系核的一些观测现象。我们发现Ｗｅｉｅｒｓｔｒａｓ函数的分形图形可以用来很好地拟合ＯＪ２８７的短时标光变。一个用Ｗｅｉｅｒｓｔｒａｓ函数构造的分形曲线与ＯＪ２８７的历史光变的线性相关系数达到了０．７３。我们计算了ＯＪ２８７光变曲线的计盒维数,信息维数和关联维数,结果表明,这些维数均大于１。我们研究了两个活动星系核（ＯＪ２８７和３Ｃ３４５）的历史光变,发现在星等和这两个物体滞留在这个星等之下的时间长度的对数之间存在线性关系。这种关系可能源于光变的分形结构。我们提出,空时点及附于该点的一个标架与Ｍｉｎｋｏｗｓｋｉ空间上的一个３阶反对称张量场对应。场中的张量取自于一个固定的张量集合。我们得到了Ｒｉｅｍａｎｎ正则坐标下引力场的一个级数表示式。我们还计算了Ｒｉｃｃｉ张量的线性近似和一级非线性近似。这有利于强引力场下的局部非线性结构分析。期望对于引力的进一步研究,通过非线性科学这门新方法的桥粱,沟通极端天文现象与基本引力相互作用之间的鸿沟     

Line profile variability of OB stars: Pulsation,rotation, clumps and magnetic fields

The variability of line profiles in spectra of bright OB stars has been studied.We obtain more than 1000 high quality spectra of δ Ori A, λ Ori A, α Cam, 19 Cep, ι Her, ρ Leo and other target stars. We revealed the line profile microvariability of small amplitude (0.5–3% in the adjacent continuum units) for all observed stars. For most stars only cyclic components of the line profile variability (LPV) at the time scales from hours to days were detected. These components seem to be connected with both the non-radial pulsations (NRP) and rotation line profile modulation. In the spectra of δ Ori A and λ Ori A we found the evidences of the stochastic LPV in spectra, probably connected with the small clumps in the stellar wind. On the basis of recent observations we discuss the origin of the magnetic field of early-type stars. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Search for variability in hydrogen-poor stars

The evolutionary status of hydrogen-poor stars is analyzed.Photoelectric observations of six objects are reported as a first step of a long-term project devoted to search for variability of a large sample of hydrogen-poor stars.The observed stars show phenomena of microvariability with an amplitude of the order of 0^m. 1 or less.Two extreme helium stars have been examined: a period in the range of 0^d.162-0^d.164 has been found for BD+ 10⁰2179, andP=0^d.1079962 for BD+13⁰3324.The mass-losing O subdwarf (sdO) BD+37⁰ 443 presents short-term fluctuations with a time-scale of several minutes and long-term variations on a scale of months. The standard sdO BD+75⁰325 is probably non-variable, although light variations of very small amplitude (m0.03) with a time-scale of about 1 hr might be present. The high gravity sdO BD+25⁰4655, which is very close to the white dwarf stage, also presents variability on a time-scale of about 13 minutes, and might be an analog of the recently discovered pulsating sdO, or hot white dwarf, PG 1159-035.The variability of the intermediate helium star HD 37776 is finally confirmed.     

Instability of LBV stars against radial oscillations

Hydrodynamic calculations of nonlinear radial oscillations of LBV stars with effective temperatures 1.5 × 10⁴ K ⩽ T _eff ⩽ 3 × 10⁴ K and luminosities 1.2 × 10⁶ L _⊙ ⩽ L ⩽ 1.9 × 10⁶ L _⊙ have been performed. Models for the evolutionary sequences of Population I stars (X = 0.7, Z = 0.02) with initial masses 70M _⊙ ⩽ M _ZAMS ⩽ 90M _⊙ at the initial helium burning stage have been used as the initial conditions. The radial oscillations develop on a dynamical time scale and are nonlinear traveling waves propagating from the core boundary to the stellar surface. The amplitude of the velocity variations for the outer layers is several hundred km s⁻¹, while the bolometric magnitude variations are within ΔM _bol ⩽ 0_· ^m 2. The onset of oscillations is not related to the κ-mechanism and is attributable to the instability of a self-gravitating envelope gas whose adiabatic index is close to its critical value of Γ₁ = 4/3 due to the dominant contribution of radiation in the internal energy and pressure. The interval of magnitude variation periods (6 days ≤ II ≤ 31 days) encompasses all currently available estimates of the microvariability periods for LBV stars, suggesting that this type of nonstationarity is pulsational in origin.