Planetary systems are made up of objects with sizes ranging from gas giant planets down to asteroids and on to micron sized dust. Dust in the zodiacal cloud in the solar system originates in the break-up of asteroids and comets and then migrates in toward the Sun due to P-R drag. The dynamical evolution of the dust is also affected by the gravitational perturbations of the solar system's planets, and the consequence of those perturbations is evident in the asymmetric and clumpy structure of the zodiacal cloud. In the last couple of years features in the cloud have been identified with asteroid collisions which occurred just a few Myr ago implying that steady state models for the zodiacal cloud will have to be reconsidered. Many extrasolar systems also harbor massive dust belts and the structures of those dust belts have been linked to perturbations from unseen planets. This paper reviews the dominant physical processes affecting the evolution of dust grains and describes the techniques which have been developed to model their dynamics and identify the sources of dust structures in both the solar system and extrasolar systems.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Clusters of galaxies are the largest bound gravitational systems in the universe. They outline the large-scale structure and thus are able to test predictions of cosmological models. Detailed studies of galaxy populations in clusters at high $z$ offer insights into galaxy evolution as a function of look-back time. Unfortunately, large homogeneous samples of galaxy clusters only exist at redshifts $<$0.5. There are around 1000 candidate clusters with photometric or otherwise estimated redshifts above 0.5, but spectroscopically confirmed clusters are still scarce in this redshift regime. Some clusters with $z>1$ have recently been identified from X-ray surveys.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Coronal mass ejections (CME) from the solar corona are the most spectacular phenomena of solar activity. Solar physicists are tried to relate CME with other forms of solar activities. CMEs are the result of a large scale rearrangement of solar magnetic field and they are often observed as an eruption of twisted magnetic fields from the solar atmosphere. SOHO/LASCO detected (http://cdaw.gsfc.nasa.gov/CME_list) more than 7500 CMEs during 1996-2003 June. The catalog contains all the CMEs with primary characteristics e.g. linear speed, central position angle, and the angular width. We will use these characteristics to study the variations of CME within these periods. The period starts from the sunspot minimum to entire sunspot maximum range where the solar activity is high. Solar proton events ($E>10MeV$) were collected from NOAA website (http:/www.lep.gsfc.nasa.gov/waves) of the associated CMEs with halo CMEs. We find from CMEs data that the occurrence of average CME rate is 121.51 per month during June 1999 to June 2003 (sunspot maximum range) whereas the occurrence of average CME rate is 41.24 per month during January 1996 to May 1999 (sunspot minimum range), although during the year 1996 (when the average sunspot number is 8.6 per month) occurrence of average CME rate is 18.16 per month. The CME occurrence rate is also correlated with the sunspot numbers with high statistically significant level. The CME number is highest in 2002 but CME is higher in 2000 than in 2001. There is an overall similarity between sunspot number and CME rates but there are differences particularly from June 1999 which is the beginning of the sunspot maximum range. The CME rate peaks in September 2001 to October 2002, which is about 1.25 year after the sunspot maximum. Similarly the average speed of CME at the time of sunspot maximum range and sunspot minimum range are 575 km/sec. and 266 km/sec. respectively. This means that the average speed of CME increases from 1996 to June 2003. The CME speed is also correlated with the sunspot numbers with less significant level than the average rate of CME occurrence. The maximum monthly average speed is about 677.3 km/sec. at the time of April 2001, which is about 5 months earlier than the second sunspot maximum. From the preliminary list of halo CME events from SOHO/LASCO during January 1996 to June 2003 we find that the occurrence rate of average halo CME events during January 1996 to May 1999 is about 1.10 per month whereas during June 1999 to June 2003 is about 4.00 per month, during the year 1996 only two halo CMEs is occurred. We also find that the average speed of halo CME events during sunspot minimum range is 838 km/sec, whereas average speed of the halo CME events during sunspot maximum range is 1000 km/sec. Although during the year 1996 the average speed of halo CME events is 451 km/sec. From the characteristics of halo CMEs in years we find that the number of halo CME increases from 1996 to 2001 and the number of halo CME is maximum in the year 2001, after that number of halo CME decreases. In the 23rd solar cycle maximum solar activity occurred during June to September 2001 we call the time as 2nd sunspot maximum time. We also find that number of high speed ($>1000\,km/sec.$) halo CME is highest during 2nd sunspot maximum range (i.e., during 2001-2002). We find from the halo CME data that average halo CME speed increases from 1996 to 1998 and then decreases from 1998 to 2000 and again increases from 2000 to 2003 and we expect that the average speed of halo CME will decrease after 2003. We find 78 solar proton events ($E >10MeV$) from CME and about 43 of them are from halo CME during 1996 to 2003. We noticed that the maximum solar proton events occurred at the second sunspot maximum, which is occurred after $1\frac12$ sunspot maximum in the 23rd solar cycle. We find there exist 5 phases of solar proton events ($E >10MeV$) data in the 23rd solar cycle. The first phase is at the sunspot minimum, 2nd phase is after two years from the sunspot minimum, 3rd phase is at the time of sunspot maximum and 4th phase occurs just one and half year (usually it is about 2/3 years) after the sunspot maximum and 5th phase occurs 2/3 years before the sunspot minimum. We find six solar proton events ($E >10MeV$) data within 1999 to 2003 with 12900 to 31700 pfu which produced strong geomagnetic storms and all of them are very high-speed halo CME. It is known that very fast CMEs $(V_{p}> 1000$km/sec.) are capable of causing extremely intensive geomagnetic storm when $D_{st} $ index ${<}\,{ -}300nT$. We find that there is a significant correlation between the speed of the CME and solar proton events ($E>10MeV$) data. Solar radius measurement at Rio de Janeiro from 1997-2000 shows that the solar radius varies in phase with the solar cycle. Astrolabes of Antalya, Rio de Janeiro and Santiago suggest that the solar radius varies in phase with the solar cycle. From the detection of solar radius variations with MDI on board SOHO it is found that the solar radius increases with the number of sunspots[l]. It appears that solar radius variation and solar neutrino flux variation with the solar cycle is due to the variation of solar core pulsations and is mainly responsible for the variation of CME and its speed that is in phase with the solar cycle. We suggest that the above-mentioned characteristics are interrelated and that a pulsating solar core may be their common origin [2].To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

According to daily observation SOHO/MDI during 1996-2003 and NSO/KP Vacuum Telescope during 1978-2003 magnetic elements with intensity of the magnetic field above background have been allocated. The knots were then identified that allowed to trace their displacement comparatively of heliographic grid. Thus, fields of speeds for the period with 1978 on 2003 have been constructed. Variations of speed meridional circulation are found out. The basic direction of speed meridional drift is directed to poles. At the same time it is shown, that during a maximum of activity at latitude less than $20^o$ arise currents in the direction of equator. Streams in the direction to equator arise and during a minimum of activity at latitude about $40-60^o$. Fields of speeds on various phases of solar cycle are constructed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Vimos-VLT Deep Survey is a spectroscopic survey aiming at collecting more than 50000 spectra down to a limiting magnitude $I_{\mathrm{AB}}=24$, and 100000 down to $I_{\mathrm{AB}}=22.5$, on a total of about 16 deg$^2$ without any color or morphology preselection. We present the $N(z)$ distribution up to $z\sim 5$, obtained from a purely magnitude-limited sample down to $I_{\mathrm{AB}}=24$, which is an important input to weak-lensing studies. We discuss the evolution of the galaxy luminosity function up to $z\sim 2$, which exhibits a very strong increase in the typical galaxy luminosity $\Delta M^*\simeq -2.5$ in the U band compared to the local value. Surveys like the VVDS also allow to study the galaxy bias as a function of redshift without assumption about its linearity, an assumption that we find to be violated in some cases. A low bias is found, and the linear bias is shown to increase with redshift.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

I review the talks given during IAU Colloquium 196, sometimes in a revised order to suggest certain connexions. The AU now, its definition, value and uncertainty, and its modern determination are contrasted with the situation in 1640. While there are differences, not least in the value of the AU and its error, some things have not changed. As an enduring constant we require: a correct theoretical framework, precise observations, and accurate calculations. The history and context of Horrocks' transit observations are set against the backdrop of our own sightings during the 2004 event, and our journeys to Carr House and other sites in Much Hoole.

The apparent success of the subsequent 1769 world-wide effort belied the limitations imposed by the ‘black drop’ effect, now said to have two causes: finite resolution and limb darkening. Some mysteries surrounding Henderson's determination of the parallax of $\alpha$ Centauri were dispelled, which led to a discussion of modern astrometry, both from the ground and in space. A passionate plea for continuing ground-based astrometry was followed by results from satellite observatories, in particular discordant values for the parallax of the Pleiades. A graph of parallax determinations since 1769 illustrates the steadily increasing precision reminiscent of a ‘Livingston curve,’ with improvement by an order of magnitude every 50 years. This progression is expected to continue, as the next space missions (Gaia, JASMINE) should better Hipparcos by large factors. Time on the Earth and our very definition of the second are quite naturally related to motion of the planets, and the dynamical history of the solar system.

The 19th-century transit efforts were the last gasp in a 250-year endeavour linking Kepler with his Victorian heirs: From the viewpoint of determining solar parallax the Venus transit must have had its day. Discussion of its history, though, can be expected to continue. Finally, I trace the progress in determining the value of the AU over nearly 400 years, and suggest that more rapid advancement could have been facilitated by the introduction of other techniques. The danger of sticking to one strategy for too long is perhaps the best lesson which the Venus transits have to offer.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss different physical aspects that may influence pulsation stability in rapidly oscillating Ap stars. We pay particular attention to the role of the magnetic field, atomic diffusion and winds and point out some of the important uncertainties involved in present studies of pulsation stability in these stars. We argue that presently the models that best reproduce the observations are those with convection suppressed, diffusion of helium, and no winds. With these models, in the region of the HR diagram where most roAp stars have been found, we predict the excitation of high order modes and the damping of low order modes, in accord with observations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

WFPC2 continuum images of the low metallicity Blue Compact Dwarf Galaxy SBS 0335-052 revealed 6 intense point source that were deemed to be super star clusters. Subsequent observations with NICMOS in the infrared continuum and Paschen α reveals that only 2 of the sources have very young stars with the other point sources as clusters that may have ended their episodes of star formation. The optical images show a probable supernova created cavity to the north of the present clusters, while the currently active star forming clusters lie at the southern end of the cluster. This indicates a possible string of induced star formation propagating from the north to the south. The presence of a large number of O stars in a small volume raises the question of whether super star clusters might be the breeding grounds for intermediate mass black holes.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Almost a century after its discovery, the phenomenon of amplitude and/or phase modulation, observed in a large percentage of the RR Lyrae stars, still lacks a widely accepted theoretical understanding. Recent attempts to theoretically explain the effect focus on two alternatives, the magnetic models and the resonances models, both involving the presence of nonradial pulsation components.

We present the ‘Blazhko project’, a large international collaboration focused on understanding the Blazhko effect. The aim of the ‘Blazhko project’ is to combine spectroscopic and photometric data from a sample of well-selected Blazhko and nonBlazhko stars, to reveal decisive information on the physical mechanism responsible for the modulation.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present first results for spectroscopic observations of galaxies in 4 clusters at $z=0.7-0.8$ and one cluster at $z=0.5$ observed by the ESO Distant Cluster Survey (EDisCS). Our spectroscopic catalogues contain 236 cluster members of our 5 clusters, and the number of members per cluster ranges from 30 to 67. Our cluster velocity dispersions are between $\sim$400 and over 1000 $\rm{km s}^{-1}$. Galaxy redshift distributions are found to be non-Gaussian and we find evidence for significant substructure in two clusters, one at $z \sim 0.79$ and another at $z \sim 0.54$; both clusters have velocity dispersions exceeding 1000 $\rm{km~s}^{-1}$. These systems have clearly not yet virialised at these epochs in qualitative agreement with CDM scenarios and their cluster velocity dispersions should not be used in the measurement of cluster mass. Our clusters have a wide range of different cluster velocity dispersions, richnesses and substructuring, and our spectroscopic data set is allowing a comprehensive insight into cluster galaxy evolution as a function of redshift and environment.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Latitude distribution of the solar convective zone rotation rate is studied by expanding it in a complete system of orthogonal modes (both symmetric and asymmetric relative to the equator). We find the solution to the problem of determination of the rotation rate of using helioseismic data available for the latitudes of $0^{\circ}$, $30^{\circ}$, $45^{\circ }$, and $60^{\circ}$ of one (for instance, the northern) hemisphere. The pole, $90^{\circ}$, will also be included into the above latitude list for the reason to be disclosed below. It is known that any rotation rate can always be represented by an expansion in a complete system of orthogonal vector spherical harmonics with a zero superscript (see, e.g., Varshalovich et al. 1988).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using the list of CMEs observed by SOHO/LASCO, we compile a daily CME counts from January 1996 to December 2003. Cross-correlations between the CME counts and other three solar activity indices, i.e., flare index, sunspot number, and photospheric magnetic flux, are examined in both real and Fourier spaces. We find that correlations are all significant in real space, but only photospheric magnetic flux has good correlation with CME counts in Fourier space. Typical periods of CME occurrence are presented and discussed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Stellar velocity dispersions in AGN are useful indicators of the black-hole mass (through the M[bull ]−σ[sstarf ] relation) and nuclear stellar populations (through the M/L ratio). We have collected near-infrared spectra of ∼40 Seyferts in the CaII triplet range in order to measure σ[sstarf ] and investigate the connection between stellar populations and AGN properties. In this poster we present a comparison between two methods to measure velocity dispersions: (1) direct fitting (DFM) and (2) cross-correlation (CCM). (1) In DFM the spectra in the CaII triplet range is modeled as a combination of a broadened and shifted stellar spectrum (observed through the same instrumental setup) and a featureless continuum. This method has the advantage of making it easy to mask out noisy regions and sky residuals. (2) CCM converts the width of the star-galaxy cross-correlation function onto a velocity dispersion. We find that these methods yield velocity dispersions consistent to within 20 km s−1 on-average. Our results are consistent to within 20 km s−1 with those objects available in the literature.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We propose a method for detecting gravitational magnification of distant sources, like quasars, due to absorber systems detected in their spectra. We first motivate the use of metal absorption lines rather than Lyman-$\alpha$ lines, then we show how to relate the observed moments of the source magnitude distribution to the mass distribution of absorbers. In order to illustrate the feasibility of the method, we use a simple model to estimate the amplitude of the effect expected for MgII absorption lines. Our model suggests that quasars behind strong MgII absorbers are in average brightened by $-0.05$ to $-0.2$ magnitude due to magnification. One must therefore revisit the claim that, in magnitude limited surveys, quasars with strong absorbers tend to be missed due to extinction effects. In addition to constraining the mass of absorber systems, applying our method will allow for the quantification of this bias.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The current version of the IAU Meteor Data Centre catalogue of photographic orbits comprising the orbital and geophysical data of 4581 meteors is applied for a more representative search of the mean orbits of bolide meteor streams among photographic meteors. We have made the search based on a computerized stream search procedure utilizing the Southworth-Hawkins D-criterion. The results are compared with the previous similar analysis made by Porubčan & Gavajdová (1994).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We discuss results of the mapping of both the stellar and gaseous kinematics of the nuclear region of 4 nearby Seyfert galaxies, on the basis of GMOS IFU observations in the spectral region of the CaII triplet (8500Å). We do not find in any of these galaxies central drops (within the central hundred parsecs or so) in the stellar velocity dispersions, as recently reported in the literature for a number of Seyferts. However, we do conclude that apparent drops are observed when there is contamination of the CaII triplet absorption lines by underlying line emission. When extended gas emission ([SIII]9068Å) is observed, the gas velocity field differs from the stellar velocity field. The latter is usually consistent with the classical “spider diagram” characteristic of disk galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We are considering below some complex problems which arise in theoretical description of the processes developing in convective zones of rotating stars. It is common knowledge that the solutions of the starting nonlinear equations of equilibrium or motion may have singularities at the rotation axis, whose elimination in the case of equations of an even more general nature including spins was treated in quantum mechanics by invoking a numerical procedure (see, e.g., Varshalovich et al. (1988)). If spin effects are disregarded, these equations, which describe general representations of conventional and Alfven velocities as expansions in orthogonal vector spherical harmonics can be cast in an analytical form Vandakurov (1999).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A class of large-scale magnetic compositions have been identified to be CME-prolific, which is characterized by a huge unipolar sunspot appearing in a large-scale extended bipolar region in synoptic magnetic charts. To understand the CMEs' origin and the nature of flux appearance, we scrutinize the long time-sequence of MDI magnetograms of high-resolution mode for super active region AR9236. Two types of magnetic features are clearly identified. They are moving magnetic features (MMFs) emanated radially from the penumbral boundary and emerging flux regions (EFRs) whose growing opposite polarities rotate out from the inner boundary of sunspot moat along helical paths in opposite directions. The interaction between the MMFs and EFRs often creates multi-fold magnetic neutral lines where the flare/CMEs initiated.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The existence of lensed quasars with splitting angles larger than $7''$ has been predicted on the basis of the cold dark matter model. We searched for these large-separation lensed quasars from the spectroscopically classified $\sim40,000$ quasars obtained by the Sloan Digital Sky Survey (SDSS), and succeeded in discovering the first lensed quasar by a cluster of galaxies, SDSS J1004+4112: It consists of four images, and the maximum separation is $14.62''$. Here we describe the discovery and the follow-up observations of this system, as well as the latest results of the large-separation lens search in the SDSS. We also present the new statistical model which fully incorporates non-sphericity of dark halos, and compare the theoretical predictions with the SDSS results.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

NOELS: How is convection suppressed in model computations?

CUNHA: We do this in two different ways. One is just to make the mixing parameter smaller and smaller. As it approaches zero we are, in e.ect, suppressing convection. The other way is simply to use the equation for radiative energy transport throughout the envelope. The results are very similar.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html