Cross-identification between the HIPPARCOS and 2MASS catalogs: The second 2MASS data release (162 million stars)

A cross-identification between the HIPPARCOS and 2MASS (the second data release, 162 million stars) catalogs has been made. This cross-identification has been used to produce a reference infrared catalog of 41143 stars.     

海量多波段星表数据的交叉证认的实现

许多天文学家需要星表来选源、证认和研究。目前国外有一些大的数据中心提供了星表查询、多源查询(即小样本交叉证认)、可视化等功能。但是随着大数据量及全波段天文时代的到来,这些服务已经越来越不能满足天文学家的需求。在详细分析了国外数据中心的服务后,提出了新的问题,并给出一套解决方案。着重讨论了任意两个星表的交叉证认和大数据量星表的交叉证认的实现,以及交叉证认结果的分类和参数的自由选择等方面的课题。     

Note on the confused designation of NGC 4496

The designation of the galaxies in NGC 4496 is in considerable confusion. The cross-identification table of these galaxies (i.e. PGC 41450, PGC 41471 and PGC 41473) in various catalogues is presented in this note and the unified designations of these galaxies are recommended.     

Cross-identification of large surveys for finding interstellar extinction

The publication of large photometric surveys and the tools for the cross-identification of their objects open up a possibility for obtaining multicolor photometry of hundreds of millions of objects. This, in turn, makes it possible not only to classify the objects and determine their parameters, but also to measure the interstellar extinction towards them and produce an extinction map for the Milky Way. The aim of this study is to develop a tool for the cross identification of objects in the most well-known surveys and test it in several sky areas. To this end, we implemented an algorithm of fast positional matching of large astronomical catalogs in small (up to one degree) sized areas with filtering of false identification. As a result, we drew in seven 0.1-degree radius areas samples of objects from the DENIS, 2MASS, SDSS, GALEX, and UKIDSS surveys, and performed the cross-identification of these surveys. We compiled the corresponding subcatalogs in the VO Table format. The tool developed as a result of this work can be used to cross-identify objects in arbitrary sky areas for the further classification and determination of stellar parameters, including the measurement of the amount of interstellar extinction.     

用MapReduce框架构建虚拟天文台数据节点

MapReduce是一种大规模分布式并行处理框架,最初被用于互联网服务中的海量数据处理,并逐渐扩展到各个行业领域。目前,虚拟天文台面临着越来越多的地面及空间望远镜观测到的海量天文数据。为了提高中国虚拟天文台数据节点处理海量天文数据的能力,首次提出基于MapReduce框架构建中国虚拟天文台数据节点的方法,并以批量星表交叉认证为例描述了具体实现过程,性能评估结果证明基于MapReduce框架构建虚拟天文台数据节点,可以在性能、扩展性与成本等多方面获得收益。     

ROSAT选射电源的性质：Ⅰ.样本

ＲＯＳＡＴ卫星的全天巡天观测到了一大批射电星系和各种活动星核,为我们研究这些活动性剧烈的河外天体的辐射机制、多波段辐射相关性以及各类星系核之间的演化联系提供了重要数据。通过将ＲＯＳＡＴ全天巡天观测与ＰＭＮ射电（５ＧＨｚ）巡天观测进行交叉证认,我们得到了６４２颗天射电源。对这些对应体随后进行的光学证认构建了一个星系和活动星系核的大样本。其中３１１个对应体（占５２％）被过去的光学观测证实为河外天体（包     

多波段巡天和LAMOST观测目标

综述了国际上多波段巡天工作的进展。其中，x射线波段列举了至今主要的x射线卫星，特别介绍了ROSAT、ASCA、Chandra和XMM—Newton的情况；光学波段主要介绍了SDSS、DEEP以及2df的星系和类星体巡天；红外波段主要介绍了2MASS和SWIRE巡天；射电波段主要介绍了NVSS和FIRST巡天。根据光谱能力和观测模式，提出了LAMOST的选题目标，分析讨论了LAMOST可以开展的交叉证认工作。     

Survey and Merging of Sunspot Catalogs

In view of the construction of new sunspot-based activity indices and proxies, we conducted a comprehensive survey of all existing catalogs providing detailed parameters of photospheric features over long time intervals. Although there are a fair number of such catalogs, a global evaluation showed that they suffer from multiple limitations: finite or fragmented time coverage, limited temporal overlap between catalogs, and, more importantly, a mismatch in contents and conventions. Starting from the existing material, we demonstrate how the information from parallel catalogs can be merged to form a much more comprehensive record of sunspots and sunspot groups. To do this, we use the uniquely detailed Debrecen Photoheliographic Data (DPD), which is already a composite of several ground-based observatories and of SOHO data, and the USAF/Mount Wilson catalog from the Solar Observing Optical Network (SOON). We also outline our cross-identification method, which was needed to match the non-overlapping solar active-region nomenclature. This proved to be the most critical and subtle step when working with multiple catalogs. This effort, focused here first on the last two solar cycles, should lead to a better central database that collects all available sunspot group parameters to address future solar-cycle studies beyond the traditional sunspot-index time series [R _i].     

Star catalogue in the fields of axial meridian circle of the Nikolaev observatory

On the base of CCD-observations made with the axial meridian circle of the Nikolaev Observatory from 2008 to 2009, we compiled a catalogue for astrometric positions and proper motions for 140321 stars located in an ecliptic zone and around high proper motion stars. The root-meansquare error for a star position is 20–65 mas in right ascension and 30–70 mas in declination. The UCAC2 catalogue is used as a reference for astrometric reductions. To derive stars’ proper motion and to estimate systematic errors of the compiled catalogue, cross-identification of the obtained data with modern astronomic catalogues Tycho2, 2MASS, CMC14, LSPM, PPMX, USNO-A2, and XPM-1.0 is performed. In addition to star position and proper motion, our catalogue contains photometric values B, V, r’, J, H, and K taken from other catalogues.     

Validation of LAMOST stellar parameters with the PASTEL catalog

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) published its first data release(DRl)in 2013,which is currently the largest dataset of stellar spectra in the world.We combine the PASTEL catalog and SIMBAD radial velocities as a testing standard to validate stellar parameters(effective temperature T_(eff),surface gravity log g,metallicity[Fe/H]and radial velocity V_r)derived from DR1.Through cross-identification of the DR1 catalogs and the PASTEL catalog,we obtain a preliminary sample of 422 stars.After removal of stellar parameter measurements from problematic spectra and applying effective temperature constraints to the sample,we compare the stellar parameters from DR1 with those from PASTEL and SIMBAD to demonstrate that the DR1 results are reliable in restricted ranges of T_(eff).We derive standard deviations of 110 K,0.19 dex and 0.11 dex for T_(eff),log g and[Fe/H]respectively when T_(eff)8000 K,and 4.91 km S~(-1) for V_r when T_(eff)10 000 K.Systematic errors are negligible except for those of V_r.In addition,metallicities in DR1 are systematically higher than those in PASTEL,in the range of PASTEL[Fe/H]-1.5.     

FIRST radio counterpart candidates to ULXs: a catalogue

Ultraluminous X-ray sources (ULXs) are the most luminous discrete X-ray sources (excluding AGNs) in the local Universe with observed luminosities above, and in many cases in excess of, 10³⁹ erg?s^?1. Their physical nature is still uncertain, and many models have been proposed to explain their unusual luminosities. Some of them favour the possible nature of these objects as extragalactic microquasars with strong beaming effects. Others, instead, rely on accretion onto intermediate-mass black holes. In any case, both interpretations offer perspectives for possible gamma-ray detections by future space missions. In order to help to constrain at present the ULX physical nature, we provide here an account of our search for radio counterparts to ULXs located in nearby galaxies, based on a systematic cross-identification of the most recent, available and extensive ULX catalogues and radio archival data. Although we ended up with 70 positional coincidences, most of them were located within the nuclear regions of these galaxies, and thus, they do not represent true ULXs. However, among these sources we identify 11 remarkable cases not previously reported of ULX and radio emission coincidence. Future follow up of these promising cases with a multi-wavelength approach could be useful to improve our understanding of the ULX phenomenon.     

Uranus and Neptune: Shape and rotation

Both Uranus and Neptune are thought to have strong zonal winds with velocities of several 100 m s⁻¹. These wind velocities, however, assume solid-body rotation periods based on Voyager 2 measurements of periodic variations in the planets’ radio signals and of fits to the planets’ magnetic fields; 17.24 h and 16.11 h for Uranus and Neptune, respectively. The realization that the radio period of Saturn does not represent the planet’s deep interior rotation and the complexity of the magnetic fields of Uranus and Neptune raise the possibility that the Voyager 2 radio and magnetic periods might not represent the deep interior rotation periods of the ice giants. Moreover, if there is deep differential rotation within Uranus and Neptune no single solid-body rotation period could characterize the bulk rotation of the planets. We use wind and shape data to investigate the rotation of Uranus and Neptune. The shapes (flattening) of the ice giants are not measured, but only inferred from atmospheric wind speeds and radio occultation measurements at a single latitude. The inferred oblateness values of Uranus and Neptune do not correspond to bodies rotating with the Voyager rotation periods. Minimization of wind velocities or dynamic heights of the 1 bar isosurfaces, constrained by the single occultation radii and gravitational coefficients of the planets, leads to solid-body rotation periods of ∼16.58 h for Uranus and ∼17.46 h for Neptune. Uranus might be rotating faster and Neptune slower than Voyager rotation speeds. We derive shapes for the planets based on these rotation rates. Wind velocities with respect to these rotation periods are essentially identical on Uranus and Neptune and wind speeds are slower than previously thought. Alternatively, if we interpret wind measurements in terms of differential rotation on cylinders there are essentially no residual atmospheric winds.     

Gravity and Topography of Moon and Planets

Planetology serves the understanding on the one hand of the solar system and on the other hand, for investigating similarities and differences, of our own planet. While observational evidence about the outer planets is very limited, substantial datasets exist for the terrestrial planets. Radar and optical images and detailed models of gravity and topography give an impressive insight into the history, composition and dynamics of moon and planets. However, there exists still significant lack of data. It is therefore recommended to equip all future satellite missions to the moon and to planets with full tensor gravity gradiometers and radar altimeters.     

DDO photometry and metallic abundances of E and SO galaxies and globular clusters of the LMC and SMC

Metallicity of 8 E and SO galaxies as well as that of red globulars of the LMC and SMC were obtained by means of DDO integrated photometry calibrated with galactic globular clusters (Bica and Pastoriza, 1983; hereafter referred to as Paper I). A correction was obtained in order to reduce the colors of the galaxies to zero redshift. The relation metallicity vsM _V for the galaxies is analyzed (adding to our sample the observations of McClure and Van den Bergh, 1968; and Faber, 1973a). For the Magellanic Clouds we found metallicity ranging from intermediate to poor.     

Substructure and the cusp and fold relations

Gravitational lensing of a background source by a foreground galaxy lens occasionally produces four images of the source. The cusp and the fold relations impose conditions on the ratios of magnifications of these four-image lenses. In this theoretical investigation, we explore the sensitivity of these relations to the presence of substructure in the lens. Starting with a smooth lens potential, we add varying amounts of substructure, while keeping the source position fixed, and find that the fold relation is a more robust indicator of substructure than the cusp relation for the images. This robustness is independent of the detailed spatial distribution of the substructure, as well as of the ellipticity of the lensing potential and the presence of external shear.     

Radiative association of C and P, and Si and P atoms

The rate coefficients for the formation of carbon monophosphide (CP) and silicon monophosphide (SiP) by radiative association are estimated for temperatures ranging from 300 to 14 100 K. In this temperature range, the radiative association rate coefficients are found to vary from  1.14 × 10⁻¹⁸  to  1.62 × 10⁻¹⁸ cm³ s⁻¹  and from  3.73 × 10⁻²⁰  to  7.03 × 10⁻²⁰ cm³ s⁻¹  for CP and SiP, respectively. In both cases, rate coefficients increase slowly with the increase in temperature.     

Fragmentation and hydration of tektites and microtektites

Abstract— An examination of data collected over the last 30 years indicates that the percent of glass fragments vs. whole splash forms in the Cenozoic microtektite strewn fields increases towards the source crater (or source region). We propose that this is due to thermal stress produced when tektites and larger microtektites fall into water near the source crater while still relatively hot (>1150 °C). We also find evidence (low major oxide totals, frothing when melted) for hydration of most of the North American tektite fragments and microtektites found in marine sediments. High-temperature mass spectrometry indicates that these tektite fragments and microtektites contain up to 3.8 wt% H₂O. The H₂O-release behavior during the high-temperature mass-spectrometric analysis, plus high CI abundances (0.05 wt%), indicate that the North American tektite fragments and microtektites were hydrated in the marine environment (i.e., the H₂O was not trapped solely on quenching from a melt). The younger Ivory Coast and Australasian microtektites do not exhibit much evidence of hydration (at least not in excess of 0.5 wt% H₂O); this suggests that the degree of hydration increases with age. In addition, we find that some glass spherules (with <65 wt% SiO₂) from the upper Eocene clinopyroxene-bearing spherule layer in the Indian Ocean have palagonitized rims. These spherules appear to have been altered in a similar fashion to the splash form K/T boundary spherules. Thus, our data indicate that tektites and microtektites that generally contain >65 wt% SiO₂ can undergo simple hydration in the marine environment, while impact glasses (with <65 wt% SiO₂) can also undergo palagonitization.     

Radii and Albedos of four Trojan asteroids and Jovian satellites 6 and 7

Thermal radiation has been detected from four asteroids of the Trojan group, and J6 and J7, the brightest of the outer satellites of Jupiter. The six objects all have exceedingly low geometric albedos of 0.02 or 0.03 according to calculations based on their known visual brightness and the measured thermal fluxes. 624 Hektor, the largest object studied here, has a radius of 110 ± 20 km, though the exact shape of this body is in question. While the sample observed in this work is small (the total number of Trojans larger than 0.25 km in radius is about 1000), the fact that all four studied have similarly low albedos suggests that this property is characterisic of the Trojans and at least two of the outer members of Jupiter's retinue of satellites. The low surface albedo of the Trojans may preclude the proposed origin of the Jovian group of comets among these bodies according to E. Rabe. Updated tables of the dimensions of all the Jovian satellites are given.     

On universal elements,and conversion procedures to and from position and velocity

An element set is advocated that is familiar (in traditional terms), and yet applicable to every type of conic-section orbit without loss of accuracy. It is not free of singularity, but this is not a serious deficiency. Conversion procedures, to and from position and velocity, are outlined, with Fortran-77 listings appended. Tests have indicated that the errors in the pair of procedures are minimal, accuracy being limited only by computer precision and the (fixed) number of iterations used in the Kepler-equation solutions.     

Local solar magnetic and velocity field development and related photospheric and chromospheric activity

We have compiled the results of our long-term studies of the local magnetic field and its activity development, derived from investigating sunspot group evolution, photoelectrically measured longitudinal magnetic and velocity fields, and measurements of sunspot proper motions. We estimate certain regularities according to which the magnetic and velocity fields, and photospheric, as well as chromospheric activities develop. We speculate about the physical background of such processes.Dedicated to Cornelis de Jager