河外星系OH超脉泽的观测和研究

自从首次发现河外星系OH超脉泽以来，30多年(特别是近10年)中对河外星系OH超脉泽的观测和研究取得了极大的进展。到目前为止已发现106个河外星系OH超脉泽，其中包括59个较高红移的源。对河外星系OH超脉泽的观测和研究，是探测和研究其所成协的活动星系核、星暴星系的中央源和拱核盘的有效工具。主要评述对河外星系OH超脉泽的搜索、观测和理论研究现状。     

河外H_2O超脉泽辐射

介绍了近年来河外Ｈ２Ｏ超脉泽的主要观测结果。Ｈ２Ｏ超脉泽通常起源于活动星系核中央的拱核盘。它们主要寄生在 Ｓｅｒｆｅｒｔ ２星系或低电离核区。至今为止，已有２０个星系探测到Ｈ２Ｏ超脉泽。脉泽辐射的各向同性光度为１０～６０００Ｌ⊙。所有超脉泽星系显示出核的活动，显然，脉泽是由核活动所产生的射电和Ｘ射线光子或激波来抽运的。Ｈ２Ｏ超脉泽倾向存在于高倾斜度的星系，这使得沿视线上的分子柱密度增高，产生足够大的放大光深。最有可能产生Ｈ２Ｏ超脉泽辐射的星系应有一个包含着射电源的侧向的分子盘以及一个适当的抽运机制。     

河外H2O超脉泽辐射

介绍了近年来河外H2O超脉泽的主要观测结果。H2O超脉泽通常起源于活动星系核中央的拱核盘。它们主要寄生在Serfert2星系或低电离核区。至今为止，已有20个星系探测到H2O超脉泽。脉泽辐射的各向同性光度为10－6000L。所有超脉泽星系显示出核的活动，显然，脉泽是由核活动所产生的射电和X射线光子或激波来抽运的。H2O超脉泽倾向存在于高倾斜度的星系，这使得沿视线上的分子柱密度增高，产生足够大的放大光深。最有可能产生H2O超脉泽辐射的星系应有一个包含着射电源的侧向的分子盘以及一个适当的抽运机制。     

河外H2O超脉泽源及与其相关的分子谱线的观测和研究

自从在活动星系核NGC4945的视线方向上发现第一个河外H2O超脉泽源以来，迄今为止已发现了19个河外H2O超脉泽源，对与活动星系核成协和河外H2O超脉泽源及分子谱线的观测和研究是探测和研究活动星系核核区中央源，拱核气体和尘埃环性质的非常有效的工具，主要评述对河外H2O超脉泽源及与其相关分子谱线的搜索，观测和理论研究现状。     

星际甲醇分子脉泽的辐射抽运研究

本项研究给出了17个具有Ⅱ类星际甲醇分子脉泽源的致密氢11区的轫致辐射、尘埃红外辐射和中心年轻恒星Layman辐射的特征．以脉泽的光子发射率和辐射亮温度作为两个主要的辐射抽运约束条件，讨论了Ⅱ类星际甲醇分子脉泽的几种可能的激发机制．我们认为热辐射亮温度为100K与致密氢Ⅱ区成协的红外辐射体很可能是Ⅱ类甲醇脉泽的抽运源．     

IRAS 10173+0828的翘曲拱核环中的 OH超脉泽

对IRAS 10173+0828的拱核环中的OH超脉泽进行MERLIN§高分辨观测,得到了拱核环为翘曲的证据,同时得到了10个速度通道中OH超脉泽的等强度轮廓线向东西方向延伸的角尺寸与其相应速度通道中峰束流量密度成正相关关系.     

星际甲醇（CH3OH）脉泽

简要综述了近年来对于星际ＣＨ３ＯＨ脉泽的观测和研究成果，对ＣＨ３ＯＨ脉泽的性质从分类，生成区域及分布，辐射特性，运动状况等方面做了介绍，并阐明了理论上对其时变特性，激发机制及河外脉泽的探讨，最后对两种类型的ＣＨ３ＯＨ脉泽作了对比和讨论。     

ON2中区OH1665 MHz右旋偏振饱和脉泽的新观测

利用法国巴黎－－默东天文台的南锡射电望远镜对ON2中区OH1665 MHz右旋偏振饱和脉泽进行观测,发现了新的成分,并且结合模型对中区的OH1665 MHz右旋偏振饱和脉泽谱线频谱进行了分析和研究。     

Mira星包层中的OH脉泽模型

采用拱星包层物质轴对称分布的模型,计算了Ｍｉｒａ星拱星包层的物质分布和速度场分布,并通过解统计平衡方程得到了ＯＨ１８ｃｍ的四条谱线的反转区。模型假定辐射压来自中心星和尘埃本身的辐射。计算中考虑了中心星的辐射、ＯＨ分子与电子的碰撞、尘埃本身的辐射和射波背景辐射等抽运机制。计算结果基本上反映了观测到的ＯＨ脉泽的径向分布和角向分布等性质。     

Some Features of the X-Ray and Radio Emission from OH Megamaser Galaxies

The properties of OH megamaser galaxies in the x-ray and radio ranges are discussed. Based on a sample of OH megamaser galaxies it is shown that the x-ray emission and the width of the OH radio line are closely related. The line width is also related to the radio emission from megamasers, but it depends only weakly on the infrared emission and this relationship is statistically less significant. The OH line width and the radio and x-ray emissions depend on the central mass of megamasers. There is a weak correlation between the radio and x-ray emissions owing to multiple scattering of synchrotron photons and bursts from the galactic nucleus. These results indicate that an active nucleus can be dominant in OH megamaser galaxies.__________Translated from Astrofizika, Vol. 48, No. 3, pp. 421–430 (August 2005).     

为什么喷流只见于一部分活动星系？

本文提出，原则上所有活动星系核都能产生喷流，但是星系核心区域介质的渗入可能使得一部分喷流被减速以至于消失。这为喷流只见于一部分活动星系的事实提供了一种可能解释，也可能是建立活动星系核结构统一的模型的一个有意义的步骤。     

A Thin Ring Model for the Oh Megamaser in Iiizw35

We present a model for the OH megamaser emission in the starburst galaxy IIIZw35. The observed diffuse and compact OH maser components in this source are explained by a single phase of unsaturated clumpy gas distributed in a thin ring structure and amplifying background continuum. We emphasize the importance of clumpiness in the OH masing medium, an effect that has not been fully appreciated previously.The model explains why multiple bright spots are seen only at the ring tangents while smoother emission is found elsewhere. Both the observed velocity gradients and the line to continuum ratios around the ring enquire a geometry where most of the seed photons come from a continuum emission which lies outside the OH ring. To explain both the OH and continuum brightness, free-free absorbing gas is required along the ring axis to partially absorb the far side of the ring. It is proposed that the required geometry arises from an inwardly propagating ring of starburst activity.     

星系翘曲盘及其统计研究

河外旋涡星系外区普遍存在翘曲结构,其特征可用干翘曲参数来描述,包括翘曲角、翘曲半径、不对称度等。一些翘曲星系表已相继发表,并用于相关的统计分析。关于翘曲盘的形成已提出多种理论机制,如星系间的潮汐相互作用、星系际介质的吸积、盘与暗晕的角动量错向以及星系际磁场的作用等。     

Bayesian approach for counting experiment statistics applied to a neutrino point source analysis

In this paper we present a model independent analysis method following Bayesian statistics to analyse data from a generic counting experiment and apply it to the search for neutrinos from point sources. We discuss a test statistic defined following a Bayesian framework that will be used in the search for a signal. In case no signal is found, we derive an upper limit without the introduction of approximations. The Bayesian approach allows us to obtain the full probability density function for both the background and the signal rate. As such, we have direct access to any signal upper limit. The upper limit derivation directly compares with a frequentist approach and is robust in the case of low-counting observations. Furthermore, it allows also to account for previous upper limits obtained by other analyses via the concept of prior information without the need of the ad hoc application of trial factors. To investigate the validity of the presented Bayesian approach, we have applied this method to the public IceCube 40-string configuration data for 10 nearby blazars and we have obtained a flux upper limit, which is in agreement with the upper limits determined via a frequentist approach. Furthermore, the upper limit obtained compares well with the previously published result of IceCube, using the same data set.