从MPIfR的校准数据看活动星系核的变化

从过去６年里ＭＰＩｆＲ的ＶＬＢＩ校准数据中挑出有２０次以上记录的１５个样本源进行了初步分析，结果表明在研究活动星系核（ＡＧＮ）的变化中，这些以及由其它射电望远镜或系统所积累的类似校准数据是很有用的。     

星系团Abell 85的动力学子结构

Abell 85是位于南半天区红移为0.055的cD星系团.基于前人的光谱观测数据和SDSS(Sloan Digital Sky Survey)数据,利用3σ方法筛选出该星系团的370个成员星系,并对其动力学情况进行了分析.从这些成员星系的空间分布和局域视向速度分布中,发现了该星系团含有4个明显的子结构,且正处于两两并合之中.这表明Abell 85处在动力学活跃的状态,远未达到动力学平衡.     

几个极高光度IRAS星系的射电频谱

使用澳大利亚致密阵（ATCA）对一个红外光度高达10^11.8-10^12.8L⊙的IRAS星系样本进行了8.6,4.8,2.4和1.4GHz的射电观测，发现其中有4个源在高频为陡谱，在较低频率上流星降低，呈峰状，峰值在几GHz。讨论了造成频谱倒转的两种可能机制：同步自吸收和free-free吸收。通过对00199－7426，02587－6336，07020－5423和21547－5823的频谱分析，我们认为free-free吸收可能导致了低频倒转谱的形成。通过对观测数据的模拟，获得了这几个源的有关物理参量。     

盘星系的内禀扁度研究

盘星系的内禀扁度对计算星系的空间倾角非常重要．对从LEDA数据库中选取的14988个盘星系进行内禀扁度的统计分析．研究表明，盘星系的内禀扁度与星系的形态密切相关．整体上说，透镜星系和不规则星系的内禀扁度qo大于旋涡星系，早型旋涡星系的内禀扁度qo大于晚型旋涡星系，其中Scd星系的内禀扁度qo最小．利用所得的qo-T关系，还对16个已知倾角的亮星系进行了倾角计算，发现与其他方法估计的空间倾角符合得较好．     

同等质量下盘状星系的颜色-尺度关系

挑选Sloan数字巡天第7次释放数据(SDSS DR7)的主星系样本中近邻的、面向的盘状星系作为星系样本,统计研究了在恒星总质量相等的情况下盘状星系的颜色和尺度之间的相关性,并对相关性的真实性进行了检验.发现对于同等质量的盘状星系,u-r颜色与尺度相关性很弱,而g-r、r-i、r-z颜色与尺度负相关,即星系的尺度越大,颜色越蓝.该结果意味着盘状星系的质量分布对其恒星形成历史影响很大,物质分布越延展的星系,其演化越慢.     

射电选BLLac（RBLs）天体的观测性质

本文给出了射电选ＱＬＬａｃ天体的完备样品及它们的观测数据并讨论了它们的各种性质。     

二个新观测到的红外选赛弗特星系

根据２５μｍ和６０μｍ间的红外谱指数及６０μｍ和１００μｍ的相对流量选择了６个天体，在１９９４年９月９日至１１日期间，利用北京天台２．１６ｍ望远镜观测了它们的光谱，经处理后，发现了一个新的Ｓｅｙｆｅｒｔ ２和一个Ｓｅｙｆｅｒｔ３星系，另外还有一个ＨＩＩ星系。     

振动Kuzmin盘中恒星的运动性质

本文研究振动盘中恒星的运动性质．所采用的势模型为它由一种具简单径向振动模态的Kuzmin盘和一种对数晕共同产生．得到的主要结论是：（1）恒星存在稳定且有序的近圆轨道；（2）盘振动对角动量较小的恒星及远离近圆轨道的恒星影响较大；（3）盘中大部分恒星的运动是有序的；（4）远离近圆轨道的恒星一般作混沌运动，并且最终可能逃逸，但在一个Hubble时间内实际逃逸的恒星比例较小；（5）盘振动可能是振动Kurmin盘中某些星团形成并长期维持的机制之一，盘振动幅度越大，盘中星团数目可能越多；在同一个星系盘中，角动量越大的星团数目可能越少．     

星系结构和动力学

从星系形成和演化的角度出发，对星系结构和动力学进行的粗略的评述，内容包括：（1）初步描述了星系中各主要成分的物理特征（空间分布，运行学和化学）及其形成和演化，（2）Damped Lyman-alpha systems(DLAs)是本地星系的化石，对其进行观测研究是HST的主要任务之一，对DLAs宽的谱线轮廓的物理机制和其恒星形成，化学演化进行了讨论，（3）目前已证明Lyman Break方法是发现高红移高恒星形成星系的有效手段，讨论了Lyman Break Galaxies的动力学过程和恒星形象，（4）旋涡星系和椭圆星系的Scaling Law是星系形成和演化所必须解释的问题，对近期该方面的研究结果作了介绍，（5）整体超星的反馈作用在星系形成和演化中起了重要作用，评述了该物理过程对星系演化的影响；（6）随着观测资料的不断积累，各种物体对河外背景辐射的贡献已成了一个重要的研究方向，讨论了宇宙整体的星形成历史和化学演化，（7）银河系是进行星系形成和演化研究的归算零点，介绍了银河系的结构，动力学及演化。     

晚型旋涡星系盘的颜色梯度与结构参数的相关关系

从Sloan数字巡天第2批释放的数据(SDSS DR2)中选择了395个在r波段亮于15等的面向晚型旋涡星系作为样本,研究了盘的颜色梯度与结构参数的关系.结果表明:盘的颜色梯度与盘的绝对星等(质量)无关;盘的颜色梯度与盘的尺度有关,越大的盘颜色梯度越陡;盘的颜色梯度与盘的颜色有关,越蓝的盘颜色梯度越陡;盘的颜色梯度与盘的表面亮度有关,越亮的盘颜色梯度越陡,并简单讨论了盘的颜色梯度与各结构参数的相关关系对晚型旋涡星系盘恒星形成历史的约束.     

Optimal extraction of cosmological information from supernova data in the presence of calibration uncertainties

We present a new technique to extract the cosmological information from high-redshift supernova data in the presence of calibration errors and extinction due to dust. While in the traditional technique the distance modulus of each supernova is determined separately, in our approach we determine all distance moduli at once, in a process that achieves a significant degree of self-calibration. The result is a much reduced sensitivity of the cosmological parameters to the calibration uncertainties. As an example, for a strawman mission similar to that outlined in the SNAP satellite proposal, the increased precision obtained with the new approach is roughly equivalent to a factor of five decrease in the calibration uncertainty.     

Calibrating Data from the Hinode/X-Ray Telescope and Associated Uncertainties

The X-Ray Telescope (XRT) onboard the Hinode satellite, launched 23 September 2006 by the Japan Aerospace Exploration Agency (JAXA), is a joint mission of Japan, the United States, and the United Kingdom to study the solar corona. In particular, XRT was designed to study solar plasmas with temperatures between 1 and 10 MK with ≈?1″ pixels (≈?2″ resolution). Prior to analysis, the data product from this instrument must be properly calibrated and data values quantified to accurately assess the information contained within. We present here the standard methods of calibration for these data. The calibration was performed on an empirical basis that uses the least complicated correction that accurately describes the data while suppressing spurious features. By analyzing the uncertainties remaining in the data after calibration, we conclude that the procedure is successful, because the remaining uncertainty after calibration is dominated by photon noise. This calibration software is available in the SolarSoft software library.     

射电天线口面温度定标

介绍一种天线口面温度定标的方法．当用这个方法对目标源进行温度定标时,由于定标源讯号和目标源讯号均由天线口面同路输入,因此波导和微波器件的传输损耗在定标的过程中被自动消除,因而这种温度定标方法能大大地提高观测资料的精度．目前无线口面温度定标方法除了在射电天文和微波天线测量中应用外,还广泛应用于雷达和无线电技术测量及微波遥感控制等．     

Transforming observational data and theoretical isochrones into the ACS/WFC Vega-mag system

We propose a zero-point photometric calibration of the data from the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) on board the Hubble Space Telescope , based on a spectrum of Vega and the most up-to-date in-flight transmission curves of the camera. This calibration is accurate at the level of a few hundredths of a magnitude. The main purpose of this effort is to transform the entire set of evolutionary models into a simple observational photometric system for ACS/WFC data, and to make them available to the astronomical community. We provide the zero-points for the most used ACS/WFC bands, and give basic recipes for calibrating both the observed data and the models. We also present the colour–magnitude diagram from ACS data of five Galactic globular clusters, spanning the metallicity range  −2.2 <[Fe/H] < −0.04  , and we provide fiducial points representing their sequences from several magnitudes below the turn-off to the red giant branch tip. The observed sequences are compared with the models in the newly defined photometric system.     

Flux Calibration of the BATC Survey and Its Application for Checking the Consistency of the Oke—Gunn Standards

1 INTRODUCTIONThe B eij lug- Ahs ona~ TaiP ei- C onnect lout Color S urvey of t he S by (Hereaft er B AT C ) ut driesthe 15 intermediate band filters to make CCD forage photometric ohs~ion. The BATCphotometric system ties its maghtude zero P~Oint to the spectro-photometric AB maghtudesystem. The AB system is a monochro~ic fi system fort introduced by Oke in 1969 with aprovisional calibration designated AB69.The AB system selects F subdwarfs around visual magnitude 9 as standa…     

A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph

A wavelength calibration system based on a laser frequency comb (LFC) was developed in a co-operation between the Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut für Quantenoptik, Garching, Germany for permanent installation at the German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands. The system was installed successfully in October 2011. By simultaneously recording the spectra from the Sun and the LFC, for each exposure a calibration curve can be derived from the known frequencies of the comb modes that is suitable for absolute calibration at the meters per second level. We briefly summarize some topics in solar physics that benefit from absolute spectroscopy and point out the advantages of LFC compared to traditional calibration techniques. We also sketch the basic setup of the VTT calibration system and its integration with the existing echelle spectrograph.     

Calibration of the Soho/Lasco C3 White Light Coronagraph

We present a detailed review of the calibration of the LASCO C3 coronagraph on the SOHO satellite. Most of the calibration has been in place since early in the mission and has been utilized to varying degrees as required by specific analysis efforts. However, using observational data from the nearly decade-long database of LASCO images, we have re-evaluated and improved many aspects of the calibration. This includes the photometric calibration, vignetting function, geometric distortion, stray light, and exposure and observation times. Using this comprehensive set of corrections we have generated and made available a set of calibrated coronal images along with a set of periodic background images to ease the accessibility and use of the LASCO database. Deceased     

Characteristics and Performance of the CCD Photometric System at Lulin Observatory

The Lulin One-meter Telescope at Lulin Observatory in Taiwan started open-use observations in January 2003. In order to evaluate the performance of the CCD photometric system, the characteristics and quality of the site, we obtained data of photometric standards as well as calibration data from February to November 2004. We report here the results of our analysis including the gain, readout noise, dark current and linearity of the CCD camera, and transformation coefficients, total throughputs, night sky brightnesses and limiting magnitudes for UBVRI bands.     

Understanding the behaviour of X-shooter via the application of a physical model

We show how traditional instrument quality control trending can be augmented by the use of a physical instrument model. The ESO VLT archive contains a detailed record of instrument diagnostics and calibration parameters while ESO quality control monitors changes in critical parameters. The physical model allows changes in positions, orientations and other physical properties of a spectrograph to be determined from standard wavelength calibration exposures via an optimisation process that seeks the physical model parameters that best reproduce the calibration features in the data. We introduce physical model parameters to the quality control monitoring. When applying this technique to archived calibration exposures, we find that the results are sensitive to the combination of parameters open to the optimisation process. Therefore we determine the most favourable set of physical parameters to optimise for each arm. We then show correlations between several physical parameters and instrument temperature sensor readings and epoch. In addition we find clear discontinuities in some physical parameter values that correspond to known maintenance events.     

Performance of the veto detector incorporated into the ZEPLIN-III experiment

The ZEPLIN-III experiment is operating in its second phase at the Boulby Underground Laboratory in search of dark matter WIMPs. The major upgrades to the instrument over its first science run include lower background photomultiplier tubes and installation of a plastic scintillator veto system. Performance results from the veto detector using calibration and science data in its first six months of operation in coincidence with ZEPLIN-III are presented. With fully automated operation and calibration, the veto system has maintained high stability and achieves near unity live time relative to ZEPLIN-III. Calibrations with a neutron source demonstrate a rejection of 60% of neutron-induced nuclear recoils in ZEPLIN-III that might otherwise be misidentified as WIMPs. This tagging efficiency reduces the expected untagged nuclear recoil background from neutrons during science data taking to a very low rate of ?0.2 events per year in the WIMP acceptance region. Additionally, the veto detector provides rejection of 28% of γ-ray induced background events, allowing the sampling of the dominant source of background in ZEPLIN-III - multiple scatter γ-rays with rare topologies. Since WIMPs will not be tagged by the veto detector, and tags due to γ-rays and neutrons are separable, this population of multiple scatter events may be characterised without biasing the analysis of candidate WIMP signals in the data.