Some results of geodetic referring of the radio telescope and SLR stations to GPS markers in the Crimean geodynamical test area Simeiz-Katsyveli

Positions of space-geodetic instruments are calculated in the International Terrestrial Reference Frame (ITRF2000) by referring the instrument reference points to the local geodetic network and GPS markers. The eccentricities of the SLR stations CrAO and CLO and the permanent GPS station CrAO with respect to the reference point of the radio telescope RT-22 are determined. The local relative deformations of the Earth’s surface are presented as shifts of the instrument reference points with respect to the nearest points of the local geodetic network and with respect to each other.     

The Luminosity-Volume test and the local hypothesis of quasars

It is shown that the luminosity-volume test for optically selected objects has an in-built bias towards increasing the average value ofV/V _m above the Euclidean value of 1/2. A more satisfactory bias-free statistic is suggested in the form of In (V/V _m), The result of applying the test to a sample from the Bright Quasar Survey (BQS) shows that the local hypothesis of quasars is consistent with the data.     

The struve dynasty in the history of astronomy in Ukraine

The impact of the Struve astronomical dynasty on the development of astronomy in Ukraine in the 19th–20th centuries is studied. First of all, the role of F.G.W. Struve and O.V. Struve in the formation of astronomical research programs at the observatories at the Kharkiv, Kyiv, Odesa, and Mykolayiv, in equipping the observatories with instruments, in practical training of astronomers as well as in the organization of astronomy-geodetic expeditions (19th century). Particular attention is paid to the activity of L.O. Struve as a director of the Astronomical observatory of Kharkiv University and his works conducted together with G.A. Shajn and B.P. Gerasimovich (20th century) as well as to the impact of his scientific and public activity, including one he made as a President of IAC, on the development of astronomy in the Soviet Union and Ukraine. A range of important documents from the archives of Russian Academy of Sciences, Institute of astronomy and State Archive of Ukraine are cited. The article was translated by the authors.     

Preliminary results of the multisite time-series campaign on the sdB pulsator PG 1325+101

I present a model for the formation and evolution of a massive disk galaxy, within a growing dark halo whose mass evolves according to cosmological simulations of structure formation. The galactic evolution is simulated with a new 3D chemo-dynamical code, including dark matter, stars and a multi-phase ISM. We follow the evolution from redshift z = 4.85 until the present epoch. The energy release by massive stars and supernovae prevents a rapid collapse of the baryonic matter and delays the maximum star formation until redshift z ≈ 1. The galaxy forms radially from inside-out and vertically from top-to-bottom. The feedback of stars leads to turbulent motions and large-scale flows in the ISM. As one result the galactic disk is significantly enriched by chemical elements synthesized in bulge stars.     

The haloing effect of the third integral

Whether Contopoulos's galactic system is separable (unlikely) or not (likely), the fact is that there exists a vicinity of the equilibrium in which numerical integration of high accuracy cannot separate the system from its image through Birkhoff's normalization of high order. To all practical purposes, stellar dynamics is then justified in pretending that the model is, in that region, structured by a so-called third integral.     

Azimuthal structures in the wind and chromosphere of the herbig Ae star ab aur. preliminary results from the MUSICOS 1992 campaign

MUSICOS (for MUlti-SIte COntinuous Spectroscopy) is an international project to facilitate and organize world-wide multi-site campaigns in high resolution spectroscopy, in view of obtaining a complete time coverage of various types of variable stellar phenomena.In the framework of this project a vast spectroscopic campaign was organized in December 1992, involving 8 sites well distributed in longitude around the Earth. The observations concerned three scientific programs, among which was the study of azimuthal structures in the wind and chromosphere of the pre-Main-Sequence Herbig Ae star AB Aur.The Hei 5876 line of AB Aur, which is formed in the expanding chromosphere of this star, in the innermost parts of its wind, was monitored at a resolution of 30000, nearly continuously for about 4 days. A spectacular variability of this line was discovered, the profile changing from pure emission to a composite profile including a deep absorption component in the course of a few hours. This variability can be the signature of azimuthal structures in the wind of AB Aur.We present the data collected during the campaign, and discuss possible interpretations of the spectacular variations of the Hei 5876 line.ESA/VILSPAUniversity of British Columbia CanadaBased on observations obtained during the MUSICOS 92 MUlti-SIte COntinuous Spectroscopic campaign from the National Solar Observatory McMath/Pierce 1.5 m, University of Hawaii 2.2 m, Beijing Observatory Xinglong 2.16 m, La Palma 4.2 m William Herschel Telescope, and Observatoire de Haute-Provence 1.52 m telescopes.Presented at the Cosmic Winds and the Heliosphere Conference in Tucson, Arizona, U.S.A., October 18–22, 1993.Visiting Astronomer, Kitt Peak National Observatory, National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.Visiting Astronomer National Solar Observatory, National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.     

A local control system for the test masses of the Virgo gravitational wave detector

The mirrors of interferometric detectors of gravitational waves (GW) are suspended in order to be isolated from external disturbances. A local control system able to keep them correctly aligned and to damp the angular modes of the suspension is necessary. In this paper we present the solution adopted for Virgo based on a CCD camera sensor and on digital controls. With this solution the mirrors are kept aligned at the level of less than 1 μrad rms, enough to lock the interferometer and start the automatic alignment system.     

The substructure of the local group

The subclustering within the Local Group is studied by means of the recently developed treediagram technique, enabling one to establish substructures of different boundness. Thirty-two galaxies from 39 listed are shown to form an interacting system which includes Milky Way and M31 giant spirals; we define the Local Group as that interacting system only. Second-level boundness indicates two clear subsystems, influenced by Milky Way and that of M31. The search of systems bound stronger, specifies several pair galaxies of similar morphology.     

The coupling coefficients of radial pulsation in third order

The third order theory of coupling is discussed regarding the radial pulsation of stellar models.     

The clustering of barred galaxies in the local Universe

We study the clustering properties of barred galaxies using data from the Sloan Digital Sky Survey. We compute projected redshift-space two-point cross-correlation functions   w _p( r _p)  for a sample of nearly 1000 galaxies for which we have performed detailed structural decompositions using the methods described in Gadotti. The sample includes 286 barred galaxies. The clustering of barred and unbarred galaxies of similar stellar mass is indistinguishable over all the scales probed (∼20 kpc–30 Mpc). This result also holds even if the sample is restricted to bars with bluer   g − i   colours (and hence younger ages). Our result also does not change if we split our sample of barred galaxies according to bar-to-total luminosity ratio, bar boxyness, effective surface brightness, length or the shape of the surface density profile within the bar. There is a hint that red, elliptical bars are more strongly clustered than red and less elliptical bars, on scales  ≳1 Mpc  , although the statistical significance is not high. We conclude that there is no significant evidence that bars are a product of mergers or interactions. We tentatively interpret the stronger clustering of the more elliptical bars as evidence that they are located in older galaxies, which reside in more massive haloes.     

Probing the gravity-induced bias with weak lensing: test of analytical results against simulations

Future weak lensing surveys will directly probe the density fluctuation in the Universe. Recent studies have shown how the statistics of the weak lensing convergence field is related to the statistics of collapsed objects. Extending earlier analytical results on the probability distribution function of the convergence field, we show that the bias associated with the convergence field can be directly related to the bias associated with the statistics of underlying overdense objects. This will provide us with a direct method to study the gravity-induced bias in galaxy clustering. Based on our analytical results, which use the hierarchical Ansatz for non-linear clustering, we study how such a bias depends on the smoothing angle and the source redshift. We compare our analytical results with ray-tracing experiments through N -body simulations of four different realistic cosmological scenarios, and find a very good match. Our study shows that the bias in the convergence map strongly depends on the background geometry and hence can help us in distinguishing different cosmological models in addition to improving our understanding of the gravity-induced bias in galaxy clustering.     

The existence of the third integral for a family of high-velocity stars

A family of high-velocity stars (Energy-19000 km²/sec², angular momentum 1150 kpc km/sec) were computed using Innanen's (1966) mass model of the Galaxy. The stars were set initially on the curve of zero velocity. The inclination diagram indicates a quasi-isolating third integral.     

Constrained simulations of the local universe – II. The nature of the local Hubble flow

Using a suite of N -body simulations in different cold dark matter (CDM) scenarios, with cosmological constant (ΛCDM) and without (OCDM, SCDM), we study the Hubble flow (σ_H) in Local Volumes (LV) around Local Group (LG) like objects found in these simulations, and compare the numerical results with the most recent observations. We show that ΛCDM and OCDM models exhibit the same behaviour of σ_H. Hence, we demonstrate that the observed coldness of the Hubble flow is not likely to be a manifestation of the dark energy, contrary to previous claims. The coldness does not constitute a problem by itself but it poses a problem to the standard ΛCDM model only if the mean density within the LV is greater than twice the mean matter cosmic density. The lack of blueshifted galaxies in the LV, outside of the LG can be considered as another manifestation of the coldness of the flow. Finally, we show that the main dynamical parameter that affects the coldness of the flow is the relative isolation of the LG, and the absence of nearby Milky Way like objects within a distance of about  3 Mpc  .