The Role of Data Centres in the Era of Electronic Publishing|How CDS weaves links towards astronomical databases and archives

The astronomy data centres, and in particular the Centre de Données astronomiques de Strasbourg (CDS), have been building electronic information services for many years. References of publications, observational data related to objects, data tables, nomenclature, have been homogenized and organized into information retrieval systems. This undertaking implied an effort of collaboration between data centres, data providers, agencies, journal editors, etc. Evolution in recent years has brought the data centres closer from the publishing process. General standards for electronic tables, tabular data, and catalogues have been proposed and implemented. With the emergence of fully electronic publication, new digital library services are being organized, and pave the way to innovative new services, linking publications to information from other sources, and making use of new methods for textual information retrieval. The data centres expect to play a key rôle in these new developments, taking advantage of their expertise in the development of value-added services, and of their long-term involvement towards a fully linked astronomy information system.     

An analysis of the radial velocity curves of close binary systems,I

The aim of the present paper will be to develop a theory of the radial-velocity changes of the components of close binary systems, with special attention to phenomena arising from finite dimensions of such components and their mutual distortion as well as irradiation. It is particularly stressed that the deformability of fluid stars and gas motions in their atmospheres can give rise to systematic differences between the observed radial velocities of such stars and those of their mass centres.In Section 2 (which follows a brief statement of the problem outlined in Section 1) we shall introduce the coordinate systems subsequently employed to treat various aspects of our problem: Section 3 will be concerned with an extraction of information from the radial-velocity component of absolute motions of the mass-centres of such stars; and in Section 4 we shall generalize the classical work by an investigation of radial velocities at any point of the apparent disks of distorted components, and their relation to the motion of their centres of mass. Section 5 will contain an evaluation of the effects of distortion, on radial velocity, averaged over the entire visible disk of the respective star at different phases; and in Section 6 we shall extend the same treatment to stars undergoing eclipses.An investigation of the effects, on the observed radial velocities, of atmospheric streaming caused by mutual irradiation of the two stars is being postponed for a subsequent communication.     

On some applications of the problem of many fixed centres to geophysics

In the present paper, using as examples the problems of four, five and six fixed centres, some applications of the problem of many fixed centres to geophysics are given.The paper was presented at the workshop on the theme The Use of Observations of the Artificial Earth Satellites in Geodesy, held in Slavsk (U.S.S.R.) from 14 to 19 April, 1980.     

Method for obtaining the combined solution for geodynamical parameters from modern space geodesy technique observation

Combined method for VLBI, GPS and SLR observation was presented. The method is based on combination of normal equation systems and local ties information for sites with collocated techniques provided by analysis centres. The combined solution for CONT02 geodesy experiment is considered.     

Orbital motion of a massive object in a dense stellar system

In this paper we show the positional oscillation of a massive object in a dense stellar system by numerical N -body simulations. We found that the central massive object, which at first is placed at rest at the centre of the surrounding spherical stellar system, promptly departs from the centre and rotates in accordance with the rotation of the stellar system, if the stellar system has an appreciable rotation. This oscillatory motion continues for a long time because of the absence of dynamical friction. Such a long-lasting oscillation may explain the asymmetric structure observed in the centres of M31 and NGC 4486B, may cause the secular flow of gaseous elements distributed in the central regions of galaxies on to the massive object, and may ignite activity in the centres of galaxies.     

The Greenwich Photo-heliographic Results (1874 – 1976): Summary of the Observations, Applications, Datasets, Definitions and Errors

The measurements of sunspot positions and areas that were published initially by the Royal Observatory, Greenwich, and subsequently by the Royal Greenwich Observatory (RGO), as the Greenwich Photo-heliographic Results (GPR), 1874?–?1976, exist in both printed and digital forms. These printed and digital sunspot datasets have been archived in various libraries and data centres. Unfortunately, however, typographic, systematic and isolated errors can be found in the various datasets. The purpose of the present paper is to begin the task of identifying and correcting these errors. In particular, the intention is to provide in one foundational paper all the necessary background information on the original solar observations, their various applications in scientific research, the format of the different digital datasets, the necessary definitions of the quantities measured, and the initial identification of errors in both the printed publications and the digital datasets. Two companion papers address the question of specific identifiable errors; namely, typographic errors in the printed publications, and both isolated and systematic errors in the digital datasets. The existence of two independently prepared digital datasets, which both contain information on sunspot positions and areas, makes it possible to outline a preliminary strategy for the development of an even more accurate digital dataset. Further work is in progress to generate an extremely reliable sunspot digital dataset, based on the programme of solar observations supported for more than a century by the Royal Observatory, Greenwich, and the Royal Greenwich Observatory. This improved dataset should be of value in many future scientific investigations.     

H110α recombination-line emission and 4.8-GHz continuum emission in the Carina nebula

We present results from observations of H110 α recombination-line emission at 4.874 GHz and the related 4.8-GHz continuum emission towards the Carina nebula using the Australia Telescope Compact Array. These data provide information on the velocity, morphology and excitation parameters of the ionized gas associated with the two bright H  ii regions within the nebula, Car I and Car II. They are consistent with both Car I and Car II being expanding ionization fronts arising from the massive star clusters Trumpler 14 and Trumpler 16, respectively. The overall continuum emission distribution at 4.8 GHz is similar to that at lower frequencies. For Car I, two compact sources are revealed that are likely to be young H  ii regions associated with triggered star formation. These results provide the first evidence of ongoing star formation in the northern region of the nebula. A close association between Car I and the molecular gas is consistent with a scenario in which Car I is currently carving out a cavity within the northern molecular cloud. The complicated kinematics associated with Car II point to expansion from at least two different centres. All that is left of the molecular cloud in this region are clumps of dense gas and dust which are likely to be responsible for shaping the striking morphology of the Car II components.     

Data Archive of the Hinode Mission

All of the Hinode telemetry data are to be reformatted and archived in the DARTS system at ISAS and mirrored to data centers around the word. The archived data are distributed to users through the Internet. This paper gives an overview of the files in the archive, including the file formats. All formats are portable and have heritage from the previous missions. From the reformatted files, index information is created for faster data search. Users can perform queries based on information contained in the index. This allows for searches to return observations that conform to particular observing conditions.     

Radiating graben-fissure systems in the Ulfrun Regio area, Venus

Radiating graben-fissure systems are common on Venus. Most are thought to be underlain by mafic dykes, fed by centrally-located magmatic centres. From previous work it has been shown that these magmatic plumbing systems can extend out up to 2000 km or more and that interaction between neighbouring systems can provide insight into the relative chronology of their magmatic centres. Systematic mapping of graben-fissure systems has potential as a tool for regional magmatic chronology and correlation on Venus.This methodology is applied to the Ulfrun Regio area (200-240°E, 0-25°N) where we mapped 47,000 graben and fissures. From these, 66 radiating systems comprised of 13,000 individual graben and fissures, and having radii of up to 2000 km have been identified, and are interpreted to be underlain by dyke swarms focussed on magmatic centres. Cross-cutting relationships among these systems and with the Hecate Chasma rift zone have been examined to provide a relative chronology for the magmatic centres. Two trends emerged: (a) an apparent younging from the southwest to northeast of the study area and (b) a cluster of older ages in the southwest, linked to the Atla Regio mantle plume.     

Stellar populations in active galactic nuclei — I. The observations

Recent observations supported by theoretical models have led to the view that giant and supergiant stars are overabundant, and/or a high-metallicity component may be present, in the stellar populations at the centres of active galaxies. Here we attempt to quantify these effects by observing the strengths of the stellar absorption lines of Mg b, Na  i and the Ca  ii triplet, as well as molecular bands such as CN and TiO. Using long-slit spectroscopic data we are able to separate the stellar populations in and around the nucleus, for a sample including normal, LINER, starburst and Seyfert galaxies.   In this paper we present the data, namely spectra of the nucleus and of a number of circumnuclear regions. Comparisons reveal gradients in both the reddening and the stellar population within the central regions of most galaxies. Detailed stellar population synthesis will be presented in a companion paper.     

河外射电源的结合阵数据的图像处理

不同类型的射电望远镜阵的分辨率差异甚大，用它们的数据进行图像处理后所得到的源结构的尺度也不一样。为了得到中间尺度的结构信息，有时我们需要把不同类型的射电望远镜阵的观测数据结合起来再进行图像处理。本文阐述我们把不同类型阵的数据结合时所用的方法；也给出我们使用的方法所获得的结果的实际例子。     

The data zoo in Astro-WISE

In this paper we describe the way the Astro-WISE information system (or simply Astro-WISE) supports the data from a wide range of instruments and combines multiple surveys and their catalogues. Astro-WISE allows ingesting of data from any optical instrument, survey or catalogue, processing of this data to create new catalogues and bringing in data from different surveys into a single catalogue, keeping all dependencies back to the original data. Full data lineage is kept on each step of compiling a new catalogue with an ability to add a new data source recursively. With these features, Astro-WISE allows not only combining and retrieving data from multiple surveys, but performing scientific data reduction and data mining down to the rawest data in the data processing chain within a single environment.     

天文文献情报工程概述

本文主要介绍中国科学院天文系统文献情报自动化建设、文献工程建设、数据工程建设、资源共享与计算机共享网建设。由于其牵涉到1984年以来的一系列工程建设呐容繁多,所以仅从文献情报现代化建设、资源共享建设出发,从整体上对各有关内容作一概述。     

Particle-mesh simulations of the Lyα forest

We have analysed short-exposure high-resolution images obtained on the William Herschel Telescope (WHT), Big Telescope Azimuthal (BTA) and CanadaFranceHawaii Telescope (CFHT) in order to investigate mechanical vibrations that are capable of reducing the high angular resolution allowed by speckle-interferometric methods. After filtering the photon noise we have computed power spectra of the image centres of gravity. In these spectra we have found vibration features that differ from one telescope to another and that vary in particular with the zenith angle. In the case of the WHT we discuss these results in terms of possible causes and in terms of degradation of the transfer function. We present some means to improve the data.     

主成分分法在天体物理中的应用

主成分分析法是从观测数据中获取主要信息的一种多种变量统计方法，它用数目少得多的新主代会原有观测量，以寻找原观测量之间的相互关系，且不损失原始数据的主要信息，尤其是对于大样本，多参量情况，该方法更为简捷而有效，目前，主成分分析法被广泛应用于三体物诸多研究领域中,介绍了主成分分法的原理和它在天体物理和它在天体物理中的广泛应用。     

A New Approach for Scientific Data Dissemination in Developing Countries: A Case of Indonesia

This short paper is a progress report on our experiences in Indonesia of collecting, integrating and disseminating both global and local scientific data across the country through the web. Our recent efforts are concentrated on improving local public access to global scientific data, and encouraging local scientific data to be more accessible for global communities. We have maintained a well-connected infrastructure and web-based information management systems to realize these objectives. This paper is especially focused on introducing the ARSIP system for mirroring global data and sharing local scientific data, and the newly developed Indonesian Scientific Index for integrating local scientific data through an automated intelligent indexing system.     

The SORCE Science Data System

The SORCE Science Data System produces total solar irradiance (TSI) and spectral solar irradiance (SSI) data products on a daily basis, which are formulated using measurements from the four primary instruments onboard the SORCE spacecraft. The Science Data System utilizes raw spacecraft and instrument telemetry, calibration data, and other ancillary information to produce and distribute a variety of data products that have been corrected for all known instrumental and operational effects. SORCE benefits from a highly optimized object-oriented data processing system in which all data are stored in a commercial relational database system, and the software itself determines the versions of data products at run-time. This unique capability facilitates optimized data storage and CPU utilization during reprocessing activities by requiring only new data versions to be generated and stored. This paper provides an overview of the SORCE data processing system, details its design, implementation, and operation, and provides details on how to access SORCE science data products.     

Determining the Solar Source of a Magnetic Cloud Using a Velocity Difference Technique

For large eruptions on the Sun, it is often a problem that the core dimming region cannot be observed due to the bright emission from the flare itself. However, spectroscopic data can provide the missing information through the measurement of Doppler velocities. In this paper we analyse the well-studied flare and coronal mass ejection that erupted on the Sun on 13 December 2006 and reached the Earth on 14 December 2006. In this example, although the imaging data were saturated at the flare site itself, by using velocity measurements we could extract information on the core dimming region, as well as on remote dimmings. The purpose of this paper is to determine more accurately the magnetic flux of the solar source region, potentially involved in the ejection, through a new technique. The results of its application are compared to the flux in the magnetic cloud observed at 1 AU, as a way to check the reliability of this technique. We analysed data from the Hinode EUV Imaging Spectrometer to estimate the Doppler velocity in the active region and its surroundings before and after the event. This allowed us to determine a Doppler velocity ‘difference’ image. We used the velocity difference image overlayed on a Michelson Doppler Imager magnetogram to identify the regions in which the blue shifts were more prominent after the event; the magnetic flux in these regions was used as a proxy for the ejected flux and compared to the magnetic cloud flux. This new method provides a more accurate flux determination in the solar source region.     

On the maximum value of the cosmic abundance of oxygen and the oxygen yield

We search for the maximum oxygen abundance in spiral galaxies. Because this maximum value is expected to occur in the centres of the most luminous galaxies, we have constructed the luminosity – central metallicity diagram for spiral galaxies, based on a large compilation of existing data on oxygen abundances of H  ii regions in spiral galaxies. We found that this diagram shows a plateau at high luminosities  (−22.3 ≲ M _B ≲−20.3)  , with a constant maximum value of the gas-phase oxygen abundance  12 + log (O/H) ∼ 8.87  . This provides strong evidence that the oxygen abundance in the centres of the most luminous metal-rich galaxies reaches the maximum attainable value of oxygen abundance. Since some fraction of the oxygen (about 0.08 dex) is expected to be locked into dust grains, the maximum value of the true gas + dust oxygen abundance in spiral galaxies is 12 + log(O/H) ∼ 8.95. This value is a factor of ∼2 higher than the recently estimated solar value. Based on the derived maximum oxygen abundance in galaxies, we found the oxygen yield to be about 0.0035, depending on the fraction of oxygen incorporated into dust grains.     

The Cannon: A Data Driving Approach to Stellar Label Determination

The new generation of large sky area spectroscopic survey project has produced nearly 10 million low-resolution stellar spectra. Based on these spectroscopic data, this paper introduces a machine learning algorithm named The Cannon. This algorithm is completely based on the known spectroscopic data of stellar atmospheric parameters (effective temperature, surface gravity, and metal abundance, etc.), this algorithm builds the characteristic vector by means of data driving, and establishes the functional relation between spectral flux characteristics and stellar parameters. Then it is applied to the observed spectral data to calculate the atmospheric parameters. The main advantage of The Cannon is that it is not directly based on any stellar physical models, it has an even higher applicability. Moreover, because of the use of full-spectrum information, even for the spectra with a low signal-to-noise ratio (SNR), it still can obtain the parameter solutions of high reliability. This algorithm has significant advantages in the data processing and parameter determination of large-scale stellar spectra. In addition, this paper presents two examples of using The Cannon to obtain the stellar parameters of K and M giants from the LAMOST spectral data.