It appears that the dynamical status of clusters and groups of galaxies is related to the large-scale structure of the Universe. A few interesting trends have been established:

(1) The Cluster Substructure-Alignment Connection by which clusters show a strong correlation between their tendency to be aligned with their neighbors and their dynamical state (as indicated by the existence of significant substructres).

(2) The Cluster Dynamics-Cluster Clustering Connection by which dynamically young clusters are more clustered than the overall cluster population.

(3) The Cluster-Supercluster Alignment Connection by which clusters of galaxies show a statistical significant tendency to be aligned with the projected major axis orientation of their parent supercluster.

(4) The Galaxy Alignment-Cluster Dynamics Connection by which red-sequence cluster bright galaxies show a significant trend to be aligned with their parent cluster major axis, especially in dynamically young clusters.

(5) The Group Richness-Shape Connection by which groups of galaxies are flatter the poorer they are.

These are strong indications that clusters develop in a hierarchical fashion by anisotropic merging of smaller units along the large-scale filamentary structures within which they are embedded.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A multi-channel SPIRIT telescope/spectroheliograph aboard the CORONAS-F satellite operating in soft X-ray and EUV ranges ($T \sim $0.05–15 MK) is an effective instrument for complex studies of CME-associated phenomena such as eruptive filaments, dimmings, coronal waves, posteruptive arcades, etc. In particular, SRIRIT observations of high-temperature (T = 5–15 MK) plasma structures in the MgXII 8.42 Å line show specific pre-CME sigmoid magnetic field configurations. Eruptions of filaments (prominences) and dimmings in a CME process are seen with a high contrast in the coronal 175 Å band (FeIX–XI) and the transition-region 304 Å (HeII) images. Our results are illustrated by several powerful eruptive events of the current solar cycle. We compare SPIRIT data with observations at other spaceborne and ground-based instruments (SOHO/EIT, Yohkoh/SXT, and H$\alpha$ images, etc.)To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present new numerical models of line-driven stellar winds of A supergiants. Statistical equilibrium (NLTE) equations of the most abundant elements are solved, and properly obtained occupation numbers are used to calculate consistent radiative force and radiative heating terms. Wind density, velocity, and temperature are calculated as solutions of the model's hydrodynamical equations. Our models allow for the calculation of the wind mass-loss rate and terminal velocity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a direct detection of the growth of large-scale structure, using weak gravitational lensing and photometric redshift data from the COMBO-17 survey. Deep $R$-band imaging of two $0.5\times0.5$ square degree fields is used to provide shear estimates for over 52000 galaxies; these are combined with photometric redshift estimates from our 17 band survey, in order to obtain a 3-D shear field. We discuss how theoretical models for evolving matter power spectra and correlation functions cab be used to find a best fit to this 3-D shear field. We present the detection of the evolution of the power, and measurements of the rate of evolution for $0<z<1$. We discuss future refinements which will improve the accuracy with which the effect can be measured.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The solar cycle in photosphere and corona reflects the internal dynamics on the Sun. According to the modern understanding the observed behavior of solar activity is related to the dynamo process in convection zone and photosphere and it is closely connected with the evolution of the coronal structures. The observational data from ground and space allow us to investigate the solar cycle as a complex phenomenon and to clarify the most important features such as polar magnetic field reversals, non-uniform distributions of the solar activity complexes and fine structure of the solar cycle.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

I review the evidence in favour of the existence of intermediate mass black holes (IMBH) in a sub-set of the class of ultraluminous X-ray source (ULX). Their X-ray properties and information on their local environments is beginning to point towards the presence of IMBHs in some, and perhaps the most luminous, ULX.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In the standard scenario of planet formation, solid planets are formed through accretion of small bodies called planetesimals. The dynamics of planetesimals is important since it controls their growth mode and timescale. Here, I briefly explain the basic dynamics of planetesimals due to the two-body gravitational relaxation process. The important roles of two-body relaxation in a planetesimal system are viscous stirring and dynamical friction. Due to viscous stirring, the random velocities (eccentricities and inclinations) of planetesimals increase, while dynamical friction realizes the energy equipartition of the random energy. I also explain the orbital repulsion of protoplanets which is the coupling effect of two-body scattering and dynamical friction.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present our cosmic shear analysis of the Galaxy Evolution from Morphology and SEDs (GEMS) survey. Imaged with the Advanced Camera for Surveys (ACS) on HST, GEMS provides high resolution imaging spanning some 800 square arcmins in the Chandra Deep Field South (CDFS). We discuss the benefits of using space-based data for weak lensing studies and show that the ACS is a very powerful instrument in this regard. We find that we are not limited by systematic errors arising from the anisotropic ACS point spread function distortion and use our cosmic shear results to place joint constraints on the matter density parameter $\Omega_m$ and the amplitude of the matter power spectrum $\sigma_8$, finding $\sigma_8(\Omega_m/0.3)^{0.62}=0.73 \pm 0.12$.

To investigate the impact of atmospheric seeing on weak lensing analysis we compare the shear measured from CDFS galaxies resolved by the COMBO-17 survey and imaged by GEMS. We find good agreement between the two surveys and a higher dispersion in the intrinsic ellipticity distribution of COMBO-17. This dispersion implies that a space-based cosmic shear analysis would yield higher signal-to-noise results compared to a ground-based cosmic shear analysis of the same galaxy sample.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

After a careful study of Mars observations obtained by Tycho Brahé (1546-1601), Kepler (1571-1630) discovered the now-called Kepler's third law. In 1627 he published his famous Tabulae Rudolphinae, a homage to his protector Rudolph II (1552-1612), tables (Kepler 1609, 1627) from which he predicted Mercury and Venus transits over the Sun. In 1629 Kepler published his Admonitio ad Astronomos… Advertisement to Astronomers (Kepler 1630), Avertissement aux Astronomes in French Au sujet de phénomènes rares et étonnants de l'an 1631: l'incursion de Vénus et de Mercure sur le Soleil. This was the beginning of the interest of French astronomers, among many others, in such transits, mostly for Venus, the subject of this paper in which dates are given in the Gregorian calendar.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyze quasi-2-dimensional slices of the SDSS EDR. Gaussian smoothing with weighting by the inverse of the selection function provides 2D density fields across the full survey depth. Superclusters (SC) are characterized by a percolation algorithm in the large-scale smoothed field. Group candidates are identified with density maxima in the small-scale smoothed field. The group mass function depends on the SC environmental density. We derive the shape-dependent 3-point correlation function and the void size distribution. These are well reproduced by the galaxies identified in high-resolution $\Lambda$CDM simulations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Model atmospheres of A and B stars are computed taking into account magnetic line blanketing. These calculations are based on the new stellar model atmosphere code LLMODELS which implements a direct treatment of the line opacities and ensures an accurate and detailed description of the line absorption. The anomalous Zeeman effect was calculated for field strengths between 1 and 40kG and a field vector perpendicular to the line of sight. The magnetically enhanced line blanketing changes the atmospheric structure and leads to a redistribution of energy in the stellar spectrum. The most noticeable feature in the optical region is the appearance of the $\lambda$5200 broad, continuum feature. However, this effect is prominent only in cool A stars and disappears for higher effective temperatures. The presence of a magnetic field produces an opposite variation of the flux distribution in the optical and the UV regions. A deficiency of the UV flux is found for the whole range of considered effective temperatures, whereas the “null wavelength region” where the flux remains unchanged shifts towards the bluer wavelengths for higher temperatures.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Why CMEs erupt is a major outstanding puzzle of solar physics. Signatures observable at the earliest stages of eruption onset may hold precious clues about the onset mechanism. We summarize and discuss observations from SOHO/EIT in EUV and from Yohkoh/SXT in soft X-rays of the pre-eruption and eruption phases of three CME expulsions, along with the eruptions' magnetic setting inferred from SOHO/MDI magnetograms. Our events involve clearly-observable filament eruptions and multiple neutral lines, and we use the magnetic settings and motions of the filaments to help infer the geometry and behavior of the associated erupting magnetic fields. Pre-eruption and early-eruption signatures include a relatively slow filament rise prior to eruption, and intensity dimmings and brightenings, both in the immediate neighborhood of the “core” (location of greatest magnetic shear) of the erupting fields and at locations remote from the core. These signatures and their relative timings place observational constraints on eruption mechanisms; our recent work has focused on implications for the so-called “tether cutting” and “breakout” models, but the same observational constraints are applicable to any model.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We report the discovery of a probable large-scale structure composed of many galaxy clumps around the known twin clusters at $z=1.26$ and $z=1.27$ in the Lynx region. Our analysis is based on deep, panoramic, and multi-colour imaging with the Suprime-Cam on the 8.2 m Subaru telescope. We apply a photometric redshift technique to extract plausible cluster members at $z\sim1.27$ down to $\sim M^\ast+2.5$. From the 2-D distribution of these photometrically selected galaxies, we newly identify seven candidates of galaxy groups or clusters where the surface density of red galaxies is significantly high ($>$5$\sigma$), in addition to the two known clusters, comprising the largest most distant supercluster ever identified.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigate the relation between circular velocity vc and bulge velocity dispersion σ in spiral galaxies, based on literature data and new spectroscopic observations. We find a strong, nearly linear vc−σ correlation with a negligible intrinsic scatter, and a striking agreement with the corresponding relation for elliptical galaxies. The least massive galaxies (σ<80 km s−1) significantly deviate from this relation. We combine this vc−σ correlation with the well-known MBHσ relation to obtain a tight correlation between circular velocity and supermassive black hole mass, and interpret this as observational evidence for a close link between supermassive black holes and the dark matter haloes in which they presumably formed. Apart from being an important ingredient for theoretical models of galaxy formation and evolution, the relation between MBH and circular velocity has the potential to become an important practical tool in estimating supermassive black hole masses in spiral galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using local helioseismology, we construct maps of the horizontal divergence of the velocity field near the solar surface and study the spectrum of solar supergranulation during the period from 1996 to 2002. Supergranulation oscillates and propagates like a wave interference pattern. The variations of the oscillation frequency with latitude and time are less than 5%. We find significant solar-cycle variations in the lifetime and the anisotropic distribution of power. We also measure the time-dependent zonal and meridional flows that advect supergranules.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Ultra-high signal-to-noise, high dispersion spectroscopy over the wavelength range \mbox{$\lambda 4487 - 4553$} shows Vega to be a rapidly rotating star $(V_{\rm eq}\sim 160\,{\rm km\,s^{-1}})$ seen almost pole-on. These data, analyzed anew, are combined with analyses of the hydrogen lines (${\rm H}\gamma, {\rm H}\beta$ and ${\rm H}\alpha$) and the latest absolute continuum flux for Vega to yield the following results: $V \sin i=21.9\pm 0.1\,{\rm km\,s^{-1}}$, polar $T_{\rm eff}=9680\pm 10\,{\rm K}$, polar $\log g=4.00\pm 0.02\,{\rm dex}$, $V_{\rm eq}=160\pm 10\,{\rm km\,s^{-1}}$, $\xi_{\rm T}=1.08\pm 0.02\,{\rm km\, s^{-1}}$ and $i=7.9\pm 0.5^{\circ}$. The variations in $T_{\rm eff}$ and $\log g$ over the photosphere total 350 K and 0.06 dex, respectively. The mean $T_{\rm eff}=9510\pm 10\,{\rm K}$ and mean $\log g=3.97\pm 0.02\,{\rm dex}$ agree with the spherical model values derived here and by others.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

After the failure of the 1761 transit to provide a reliable value for the astronomical unit, the focus shifted to the 1769 event, and Britain mounted an ambitious program, with overseas observing parties dispatched to North Cape (Norway), Hudson Bay (Canada) and newly-discovered Tahiti in the Pacific. Lieutenant James Cook was in charge of the Tahitian expedition, ably assisted by fellow-astronomer, Charles Green, and they were supplied by the Royal Society and the Royal Observatory at Greenwich with telescopes and other scientific instruments. The main observing site was set up at Fort Venus, and supplementary transit stations were established on Irioa Island (Moorea) and Taaupiri Island (off the east coast of Tahiti). June 3 was warm and clear, and all observers successfully recorded the transit, but on the journey home ‘the curse of the transit’ prevailed and more than half of them fell ill and died. Back in England, Cook wrote up the transit observations for the Philosophical Transactions of the Royal Society, but for some inexplicable reason only used data obtained at Fort Venus. It was left to Oxford astronomer, Professor Thomas Hornsby, to derive a meaningful figure for the solar parallax, and he utilized the Tahitian data and observations made at four other sites to arrive at a figure of 8$\rlap . ^{\prime\prime}$78. But discordant results obtained by other researchers fuelled controversy over the effectiveness of transits of Venus as a valid means of determining the astronomical unit. In fact, the solar parallax obtained by Hornsby was remarkably similar to the currently-accepted value of 8$\rlap . ^{\prime\prime}$794148, thereby discrediting Beaglehole's oft-quoted claim that the Tahitian observations were a failure. Although more than a dozen men were involved in the Tahitian transit program, most of their records have been lost, and remarkably few of the instruments they employed can now be identified. Yet for those of us with Pacific affiliations, Cook's first voyage to the South Seas occupies a special place in transit of Venus history.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Nowadays, more than one hundred extra-solar planets are known, and about a dozen of multi-planetary systems have been discovered. Most of them have been detected by the radial velocity (RV) method. The recovery of orbital parameters from RV data leads to several problems. Usually RV data cover irregularly a short time interval which is frequently shorter than the orbital period of the most distant planet. Moreover, observations contain a noise due to the instabilities of the star. The distribution of this noise is unknown. A precise determination of the dynamical state of a multi-planetary system is important for understanding its stability and evolution. In most cases observers determine the orbital parameters for multi-planetary systems just fitting a sum of Keplerian orbits. The parameters obtained in such a way are in most cases the only accessible data about an extra-solar system because the observes very rarely publish their observations. However, the parameters from a multi-Keplerian fit as it has already been observed by many authors, cannot be interpreted as the osculating elements for actual planetary orbits. Moreover, these parameters can be considered as Keplerian elements of: relative, barycentric or Jacobi orbits. One can find arguments that the interpretation of parameters from a multi-Keplerian fit as elements of Keplerian orbits in the Jacobi coordinates is the most proper one, see [Lee and Peale, 2002; Goździewski et al. 2003].To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Cosmic shear is an essential cosmological tool, breaking degeneracies inherent to CMB data and providing an independent check of cosmological parameters. Upcoming cosmic shear surveys with photometric redshift information will enable tighter constraints to be placed on cosmological parameters, and allow us to explore how dark matter evolves. A Monte Carlo method to rapidly simulate mock surveys enables us to estimate the covariance matrix for the shear correlation functions, and hence the expected errors on cosmological parameter estimates given survey specifications. We also make brief remarks on the separation of the cosmic shear signal from any due to intrinsic galaxy alignments.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A 2-dimensional Doppler coronagraph “NOGIS” (NOrikura Green-line Imaging System) at the Norikura Solar Observatory, NAOJ, is a unique imaging system that can provide both intensity and Doppler velocity of 2 MK plasma from the green coronal line emission $\lambda$5303 Å of Fe xiv. We present the first detection of a CME onset by NOGIS. The event was originally induced by a C9.1 confined flare that occurred on 2003 June 1 at an active region NOAA $\#$10365 near the limb. This flare triggered a filament eruption in AR 10365, which later evolved into a partial halo CME as well as an M6.5 flare at the same AR 10365 on 2003 June 2. The CME originated in a complex of two neighboring magnetic flux systems across the solar equator: AR 10365 and a bundle of face-on tall coronal loops. NOGIS observed i) a density enhancement in between the two flux systems in the early phase, ii) a blue-shifted bubble and jet that later appeared as (a part of) the CME, and iii) a red-shifted wave that triggered a periodic fluctuations in Doppler shifts in the face-on loops. These features are crucial to understand unsolved problems on a CME initiation (e.g., mass supply, magnetic configuration, and trigger mechanism) and on coronal loop oscillations (e.g., trigger and damping mechanisms). We stress a possibility that interaction between separatrices of the two flux systems played a key role on our event.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html