新发现的6个X选类星体和1个Seyfert星系

利用ＲＯＳＡＴＶＬＡ方法筛选，从ＲＯＳＡＴＸ射线源中选出了一批新的ＢＬＬａｃ天体和类星体的候选体．１９９６年１２月８日至１７日，利用北京天文台２．１６ｍ望远镜和ＯＭＲ摄谱仪，对这批新候选体进行了光谱认证．经ＳＵＮ工作站处理，又发现了５个新的Ｘ选类星体和１个Ｓｅｙｆｅｒｔ星系．此外，在扩大光谱波长覆盖范围到８５００的条件下，重新观测了作者去年所发现的ＢＬＬａｃ天体，结果发现２３１８＋３０４在７２５９处有一很强的Ｈα６５６３＋［ＮＩ］６５４８，６５８３发射线．因此，可以确定２３１８＋３０４是一个类星体，而不是一个ＢＬＬａｃ天体．     

新发现7个X选BLLac天体和1个类星体

利用ＲＯＳＡＴ－ＶＬＡ方法筛选，从ＲＯＳＡＴＸ射线源中选出了１９个新ＢＬＬａｃ天体和类星体的候选体，在１９９４年至１９９６年１月期间，利用北京天台２．１６ｍ望远镜对其中１６个进行光谱证认，发现了７个新的Ｘ选ＢＬＬａｃ天体及一个类星体，类星体的红外移值为：Ｚ＝０．３３１±０．００１５。     

5个新发现的X选BL Lac天体

利用ＲＯＳＡＴ－ＶＬＡ方法筛选，从ＲＯＰＳＡＴ Ｘ射线源中选出了一批新的ＢＬ Ｌａｃ天体和类星体的候选体。１９９６年１２月８日至１７日，利用北京天文台２．１６ｍ望远镜和新从美国引进的ＯＭＲ摄谱仪，对这批新候选体进行了光谱认证。经ＳＵＮ工作站处理，又发现了５个新的Ｘ选ＢＬ Ｌａｃ天体。     

X选BL Lac天体的某些性质（II）

本文对Ｘ射线选择ＢＬＬａｃ天体（ＸＢＬｓ）的完备样品进行了较细致的研究，讨论了该样品各观测量的分析，最新发现的几例Ｘ射线和ＲＯＳＡＴ选择的ＢＬＬａｃ天体的Ｈｕｂｂｌｅ关系及ＢＬＬａｃ天体的红移起源问题。     

BL Lac天体和FR—I射电星系的统一模型（I）

从射电结构的角度评述了ＢＬＬａｃ天体和ＦＲ－Ｉ射电星系的统一模型的最新进展，内容包括射电结构，延展射电光度（Ｐｅｘｔ），最大角尺度（ＬＡＳ），射电核主导系数（ｆ）的比较以及对相对论聚束的测试。最新的射电观测资料表明ＸＢＬｓ是介于ＦＲ－Ｉ和ＲＢＬｓ之间的过渡型天体，这对ＢＬＬａｃ天体是聚束的ＦＲ－Ｉ射电星系提供了一个很好的证据。     

BL Lac天体处于高态与低态时的短时标光变的差异及机制研究

分析了１９９３－１９９５年ＢＬＬａｃ、ＯＪ２８７和ＰＫＳ０７３５＋１７８三颗ＢＬＬａｃ天体光变的监测结果,并结合文献上他人发表的资料,发现一些ＢＬＬａｃ天体处于高态时活动性较强,短时标光变频繁发生,而处于低态时活动性较弱,短时标光变很少发生．文中提出活动星系核的相对论性喷流方向会改变,从而导致长期光变;高态是喷流方向与观测者视线夹角较小的表现,而低态则是夹角较大的表现。利用该模型能够解释ＢＬＬａｃ天体短时标光变行为在高态和低态下的差别,并能很好地解释Ｔａｋａｌｏ等人监测ＯＪ２８７时发现的新现象．     

8个ROSAT X射线源和5G射电源被证认为类星体

１９９５年５月，使用２．１６ｍ望远镜对ＲＯＳＡＴ Ｘ射线源进行光学证认期间，发现８个ＲＯＳＡＴ Ｘ射线源和５Ｇ射电源的光学对应体是以前未发现的类星体，其红移范围从０．３３３至１．０９１。本文给出了这些类星体的多波段特性。     

8个ROSAT X射线源和5G射电源被证认为类星体

１９９５年５月，使用２．１６ｍ望远镜对ＲＯＳＡＴＸ射线源进行光学证认期间，发现８个ＲＯＳＡＴＸ射线源和５Ｇ射电源的光学对应体是以前未发现的类星体，其红移范围从０．３３３至１．０９１。本文给出了这些类星体的多波段特性。     

新发现的X射线选活动星系核,白矮星和激变变星

为了研究ＲＯＳＡＴ Ｘ射线选亮近类星体巡天的选择判据，从１９９５年４月至１９９６年１０月期间，利用北京天台２．１６米望远镜进行了试验观测，发现了７３个类星体，２７个赛弗特星系，１个ＢＬ Ｌａｃ侯选体，１个白矮星和１个激变变星。     

BLLac天体AO0235＋164在5GHz上的VLBI观测

应用５ＧＨｚＶＬＢＩ技术在历元１９９７．１２的观测结果,给出ＢＬＬａｃ天体ＡＯ０２３５＋１６４在毫角秒尺度上的最新图像,该致密天体的射电结构由一个亮核所支配,另外在东北和西南方向各存在一个相对较弱的子源,其中东北方向的子源要比西南方向的明显得多,模型拟合结果显示,该源的喷流位置角为６６．４°,该数值超过以往的一次观测结果,根据流量密度随时间的变化关系。我们发现ＡＯ０２３５＋１６４在波长６ｃｍ上可能     

Catalogue of Shakhbazian compact groups of galaxies. X

The tenth part of the catalogue of Shakhbazian groups contains the positions and references of all the galaxies of the following 35 groups (north of δ > +2°30'): Shkh 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 354, 355, 356, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377. For the estimation of the coordinates the Digitized Sky Survey was used.     

Interstellar heliospheric probe/heliospheric boundary explorer mission—a mission to the outermost boundaries of the solar system

The Sun, driving a supersonic solar wind, cuts out of the local interstellar medium a giant plasma bubble, the heliosphere. ESA, jointly with NASA, has had an important role in the development of our current understanding of the Suns immediate neighborhood. Ulysses is the only spacecraft exploring the third, out-of-ecliptic dimension, while SOHO has allowed us to better understand the influence of the Sun and to image the glow of interstellar matter in the heliosphere. Voyager 1 has recently encountered the innermost boundary of this plasma bubble, the termination shock, and is returning exciting yet puzzling data of this remote region. The next logical step is to leave the heliosphere and to thereby map out in unprecedented detail the structure of the outer heliosphere and its boundaries, the termination shock, the heliosheath, the heliopause, and, after leaving the heliosphere, to discover the true nature of the hydrogen wall, the bow shock, and the local interstellar medium beyond. This will greatly advance our understanding of the heliosphere that is the best-known example for astrospheres as found around other stars. Thus, IHP/HEX will allow us to discover, explore, and understand fundamental astrophysical processes in the largest accessible plasma laboratory, the heliosphere.     

Photometric study of the major satellites of Uranus

In this paper, we analyze the results of ground-based and space-born photometric observations of the major satellites of Uranus—Miranda, Ariel, Umbriel, Titania, and Oberon. All sets of photometric observations of the satellites available in the literature were examined for uniformity and systematic differences and summarized to a unified set by wavelength ranging from 0.25 to 2.4 μm. This set covers the interval of phase angles from 0.034° to 35°. The compound phase curves of brightness of the satellites in the spectral bands at 0.25, 0.41, 0.48, 0.56, 0.75, 0.91, 1.4, and 1.8 μm, which include a pronounced opposition surge and linear part, were constructed. For each satellite, the geometric albedo was found in different spectral bands taking into account the brightness opposition effect, and its spectral dependence was studied. It has been shown that the reflectance of the satellites linearly depends on the wavelength at different phase angles, but has different spectral gradients. The parameters of the phase functions of brightness, including the amplitude and the angular width of the brightness opposition surge, the phase coefficient, and the phase angle at which the nonlinear increase in brightness starts, were determined and their dependences on wavelength and geometric albedo were analyzed. Our investigations show that, in their optical properties, the satellites Miranda and Ariel, Titania and Oberon, and Umbriel present three types of surfaces. The observed parameters of the brightness opposition effect for the Uranian satellites, some ice satellites of Jupiter and Saturn, and the E-and S-type asteroids are analyzed and compared within the framework of the coherent backscattering and mutual shadowing mechanisms.     

The Interstellar Heliopause Probe: Heliospheric Boundary Explorer Mission to the Interstellar Medium

The Sun, driving a supersonic solar wind, cuts out of the local interstellar medium a giant plasma bubble, the heliosphere. ESA, jointly with NASA, has had an important role in the development of our current understanding of the Suns’ immediate neighborhood. Ulysses is the only spacecraft exploring the third, out-of-ecliptic dimension, while SOHO has allowed us to better understand the influence of the Sun and to image the glow of interstellar matter in the heliosphere. Voyager 1 has recently encountered the innermost boundary of this plasma bubble, the termination shock, and is returning exciting yet puzzling data of this remote region. The next logical step is to leave the heliosphere and to thereby map out in unprecedented detail the structure of the outer heliosphere and its boundaries, the termination shock, the heliosheath, the heliopause, and, after leaving the heliosphere, to discover the true nature of the hydrogen wall, the bow shock, and the local interstellar medium beyond. This will greatly advance our understanding of the heliosphere that is the best-known example for astrospheres as found around other stars. Thus, IHP/HEX will allow us to discover, explore, and understand fundamental astrophysical processes in the largest accessible plasma laboratory, the heliosphere.     

Peripheral Structures of Planetary Systems

We analyze the conditions for the formation and time evolution of peripheral comet structures of solar-type planetary systems. In the Solar system, these include the Kuiper belt, the Oort cloud, the comet spear, and the Galactic comet ring that marks the Galactic orbit of the Sun. We consider the role of the viscosity of a protoplanetary gas–dust disk, major planets, field stars, globular clusters, giant molecular clouds, and the Galactic gravitational field in the formation of these peripheral structures marked by comets and asteroids. We give a list of the closest past and future passages of neighboring stars through the solar Oort cloud that perturb the motion of its comets and, thus, contribute to the enhancement of its cometary activity, on the one hand, and to the replenishment of the solar comet spear with new members, on the other hand.     

Infrared spectra of gaseous mononitriles: Application to the atmosphere of Titan

A list of volatile nitriles, not yet detected in the atmosphere of Titan, but likely to be present in this environment, has been selected: acetonitrile, propionitrile, acrylonitrile, crotononitrile, allyl cyanide, methacrylonitrile, and cyanopropyne. The spectra of these compounds in the gas phase have been systematically studied, in the mid- and far-infrared ranges. For each selected nitrile, the most intense vibration bands have been determined. Their strengths have been characterized by estimating the monochromatic absorption coefficient at the maximum(s) of the bands, and the integrated absorbance over the entire band. Then, in order to estimate the detectability of the selected compounds by infrared spectroscopy in the atmosphere of Titan, the data obtained have been extrapolated to the case of Titan.     

An axion-like scalar field environment effect on binary black hole merger

The environment, such as an accretion disk, could modify the signal of the gravitational wave from astrophysical black hole binaries. In this article, we model the matter field around intermediatemass binary black holes by means of an axion-like scalar field and investigate their joint evolution. In detail, we consider equal mass binary black holes surrounded by a shell of axion-like scalar field both in spherically symmetric and non-spherically symmetric cases, and with different strengths of the scalar field. Our result shows that the environmental scalar field could essentially modify the dynamics. Firstly,in the spherically symmetric case, with increase of the scalar field strength, the number of circular orbits for the binary black hole is reduced. This means that the scalar field could significantly accelerate the merger process. Secondly, once the scalar field strength exceeds a certain critical value, the scalar field could collapse into a third black hole with its mass being larger than that of the binary. Consequently,the new black hole that collapses from the environmental scalar field could accrete the binary promptly and the binary collides head-on with each other. In this process, there is almost no quadrupole signal produced, and, consequently, the gravitational wave is greatly suppressed. Thirdly, when the scalar field strength is relatively smaller than the critical value, the black hole orbit could develop eccentricity through accretion of the scalar field. Fourthly, during the initial stage of the inspiral, the gravitational attractive force from the axion-like scalar field could induce a sudden turn in the binary orbits, hence resulting in a transient wiggle in the gravitational waveform. Finally, in the non-spherical case, the scalar field could gravitationally attract the binary moving toward the center of mass for the scalar field and slow down the merger process.     

A subsample of white dwarfs among the fbs blue stellar objects

Results are reported from studies of a subsample of white dwarfs in the second part of the FBS survey. Of the 217 WD identified in the FBS, most are DA dwarfs, but the subclasses DO, DOB, DB, DAB, DAZ, DZ, and DC are also encountered. Multiwavelength studies are conducted on the sample from the FBS survey: of the 217 white dwarfs, 178 coincide with 2MASS sources, GALEX (ultraviolet) data exist for 155, 23 are ROSAT x-ray sources, and SDSS data with stellar magnitudes in five photometric bands, u, g, r, i, and z, are available for 120. The WD sample from the FBS survey is compared with similar surveys (PG and SDSS). Average B and R magnitudes, as well as an average value of the length of the low dispersion spectra of white dwarfs from the DFBS are also given.     

Multi-technique Analysis of the Solar 10.7 cm Radio Flux Time-Series in Relation to Predictability

We studied the predictability of the 10.7 cm solar radio flux by using stationary and non-stationary time-series analysis techniques of fractal theory to find the correlation exponent, the spectral exponent, the Hurst exponent, and the fluctuation exponent of the time series. The Hurst exponent was determined, from which the fractal dimension and consequently the predictability was evaluated. The results suggest that stationary methods of analysis yield inconsistent result, that is, amongst the four techniques used, the values of the exponents show great disparity. While two of the techniques, namely the auto-correlation function analysis and the spectral analysis, indicate long-term positive correlation, the other two methods, specifically the Hurst rescaled range-analysis and the fluctuation analysis, clearly exhibit the anti-correlated nature of the time series. The two non-stationary methods, that is, the discrete wavelet transform and the centered moving-average analysis, yielded values of the Hurst exponent that are indicative of positive correlation, of persistent behavior, and also showed that the time series is predictable to a certain extent.     

地外生命搜索和太阳系外的行星的发现

阐述地外生命搜索的意义，手段和现状，地外生命搜索的SETI计划及其发展，并着重介绍太阳系外的行星系统的发现，它的目的，成果以及未来。太阳系外的行星系统的发展是当代天文学最时髦的，也将是未来21世纪成果最丰富的研究领域之一，从1992年第一个确认了脉冲星PSR 1257＋12的行星系统以来，1995年确认主序星51Peg有一颗行星，至2001年5月，已经发现了60个太阳系外的行星系统，太阳系外的行星系统的发现与地外生命搜索研究是密不可分的，新的发现也提出了很多新的谜，这项研究近10年来发展很快，它的研究也促进了航天学，宇宙化学，天文生物学乃至哲学等其他学科的发展。