In the present study a time series analysis of three of the most well-known Sun activity data series is made: 1) the Hoyt-Schatten (Group Sunspot Number $\mbox{\textit{Rg}}$)(Hoyt & Schatten 1988); 2) the Schove and 3) the Greenland (Dye-3 ice probe) ‘cosmogenic’ $^{10}Be$ concentration series (Schove 1983, Beer et al. 1998). The series “1” is based on instrumental observations for the last $\sim$400 years. The series “2” is a reconstruction of all Schwabe-Wolf cycle magnitudes after AD 296 by use of historical reports mainly for auroras and naked-eye visible sunspots. The series “3” is an indicator for the processes in outer solar corona and interplanetary space for the epoch AD 1423–1985. Two independent methods for time series analysis are used: 1) the $T$-$R$ periodogramm analysis (Komitov, 1986); 2) the method of Kaftan (2002).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Solar radio fine structures (FSs) may be as an important diagnostics stool to draw the evolution map of the flare loop in the initial phase of solar flares. Also, it may be an important signature of the initial phase of CMEs. Here we analyzed a series of solar radio bursts with drift pulsation structures (DPS) and FSs during the former part of the 23rd solar activity cycle. Found they were associated with CMEs, and got some important statistic conclusions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The cluster soft excess emission indicates the presence of large amounts of warm gas ($T\sim10^6$ K) in the neighborhood of galaxy clusters. Among the clusters that display this phenomenon is the Coma cluster, the nearest rich galaxy cluster. The excess emission is more prominent at the cluster's outskirts than at its center. Detailed studies of its large-scale emission–up to $\sim 2.6$ Mpc from the cluster's center–reveal that these warm baryons are as massive as, or possibly more massive than, the well-known hot intra-cluster medium ($T\sim10^8$ K). A possible interpretation of the excess emission from the Coma cluster is radiation from low-density filaments located in the neighborhood of the cluster. In this case, the filaments would extend for much larger distances, or feature higher density, than predicted by current cosmological simulations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

This presentation has the following goals: (i) to explain, within a historical context, some of the difficulties in disentangling our Galaxy's three-dimensional structure; (ii) to summarise in broad terms what we presently know of this structure, concentrating on those features inferred from accurate distance measurements; (iii) to illustrate selected aspects in a visually stimulating manner; and (iv) to give a foretaste of the exciting results that lie ahead with future space astrometric experiments. The public lecture given in Preston, UK on 9 June 2004 employed 3-d visualisation techniques using polarised light to illustrate the talk.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The shape and size of a galaxy-mass dark matter halo can only be measured using a luminous tracer, such as stars, gas or photons. In the last case, gravitational lensing of extended background sources provides many paths for photons to sample the gravitational potential of the lensing galaxy. Multiple independent light paths provide tighter constraints on the mass profile of the lens galaxy than is possible from single path sampled by the lensed images of unresolved sources.

Using software specifically developed to model resolved images, we analyse the optical and radio Einstein ring systems 0047-2808 and MG1549+3047. For 0047-2808, elliptical pseudo-isothermal models (e.g. SIE, PIEP) are able to reproduce the lensed image well, with a surface mass power-law $\Sigma \propto r^{-\gamma}$, best fitted by $\gamma = 1.07 \pm 0.03$, which is slightly steeper than isothermal. Using a stars-plus-halo model, we find the projected halo is rounder than the visible galaxy (axis ratio $0.82 \pm 0.01$) and aligned closely with the stars (offset $8^{\circ} \pm 1$). Preliminary results for MG1549+3047 also rule out the constant M/L model. A stars + PIEP model suggests a very round (axis ratio $\ge 0.98$) halo.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the results from a new 120 ks XMM-Newton observation of Sérsic 159-03. A previous XMM-Newton observation of this cluster shows the presence of a soft X-ray excess in the outer parts of the cluster, which is possibly connected to the interaction between the cluster and the gas from the surrounding filaments. We exploit the long exposure time to constrain the excess emission and discuss the relation to the warm-hot intergalactic medium. Furthermore, we show a high-resolution RGS spectrum of the core of the cluster and radial profiles from EPIC, which allow us to constrain the internal temperature structure and elemental abundances.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The measurements of the Doppler effect of the photosphere showed the presence of the persistent periodicity 159.9655(5) min. It is interpreted as by-product of the fast-rotating central solar core.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

NOELS: What are the uncertainties in the di.usion velocities? What can we do if we would like to multiply or divide it by something? How can we play with that? What would be your best guess?To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a new sample of 30 nearby (z < 0.2) BL Lacs, selected to study the nuclear as well as the large scale properties of low power radio sources. New VLA and VLBA radio data have been obtained to discuss the morphology, physical properties, and overall properties of the sample. We show that the distributions of total radio power and intrinsic core radio power for BL Lacs are consistent with their being drawn from the same population as FR I radio galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A distinct coronal inflow has been discovered after $\sim90\,{\rm min}$ of prominence eruption associated coronal mass ejection (CME) on 05-Mar-2000 by EIT (Extreme ultraviolet Imaging Telescope) aboard SoHO (Solar and Heliospheric Observatory). Evolution of the prominence seen by EIT was tracked into the LASCO/C2 and C3 field-of-view (FOV; $4{-}10 R_{\odot}$) where it developed as the core of a typical three-part CME. The speed of the inflow, which was only seen in EIT FOV, was 70-80 km/s at a height between 1.5-1.2 $R_{\odot}$ coinciding with the deceleration phase of the core of the CME in LASCO/C2. In contrast to dark inflow structures observed earlier and interpreted as plasma void moving down, the inflow reported here was bright. The inflow showed a constant deceleration and followed a curved path suggesting the apex of a contracting magnetic loop sliding down along other field linesTo search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We evaluate asteroid orbital uncertainties from the discovery night onwards using 6D orbit computation tools based on statistical techniques. In particular, we outline a new nonlinear Monte Carlo technique of phase-space sampling that helps us in assessing the nonlinear phase transition from extended orbital-element distributions to well-constrained ones as the observational arc and number of observations grows. We apply the statistical techniques for near-Earth asteroid 2004 AS$_1$ to examine the time evolution of the orbital uncertainties and to assess the asteroid impact risk immediately after discovery. We start with the technique of statistical ranging for exiguous data, continue with the phase-space sampling technique for moderate data, and conclude with the standard least-squares fit for extensive data.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

During the 25 years that the author has been involved in astrometry, the quality of ground-based parallaxes has increased by about a factor of 10 (from 3 mas to 0.3 mas), but the quantity has increased by only a few hundred. When asked, the average astronomer will cite the $H^2$ space missions (Hubble and Hipparcos) as the great advances in astrometry even thought the ground-based work has played a critical role in the understanding classes of stars such as the L- and T-dwarfs. The next decade promises stunning advances in both the quality and quantity of parallax measurements, and both ground- and space-based projects will play significant roles. The Gaia space mission and the various ground-based telescopes with large etendue (DMT, LSST, Pan-STARRS, etc.) will improve the quality or quantity (or both) by factors of a thousand or more. The situation will be discussed, and the author will express his hope that he might live long enough to see the fruits of these labors.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

This paper describes some useful results that can be obtained through long-term infrared photometric monitoring of Seyfert galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We describe our experiences with on-orbit calibration of, and scientific observations with, the Fine Guidance Sensors (FGS), white-light interferometers aboard Hubble Space Telescope. Our original goal, 1 milliarcsecond precision parallaxes, has been exceeded on average by a factor of three, despite a mechanically noisy on-orbit environment, the necessary self-calibration of the FGS, and significant temporal changes in our instruments. To obtain accurate absolute parallaxes from these small fields of view ($3^\prime \times 15^\prime$) observations requires a significant amount of ancillary reference star information. These data also permit an independent estimate of interstellar absorption, critical in determining target absolute magnitudes, M$_V$, often the key result of a parallax program. With these techniques we and our collaborators have obtained absolute parallaxes for 21 astrophysically interesting objects. We briefly discuss a recent determination of the parallax of the Pleiades. HST routinely produces parallaxes with half the error of the best Hipparcos results, a precision that continues down to target $V = 15$. The FGS will remain a competitive astrometric tool for the generation of high-precision parallaxes until the advent of longer-baseline space-based interferometers (SIM), or the failure of some key HST component.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The discovery of diffuse synchrotron radio emission and, more recently, of the hard X-ray (HXR) tails have triggered a growing interest about non-thermal phenomena in galaxy clusters. After a brief review of the most important evidences for non-thermal emission, I will focus on the origin of the emitting particles and of the hadronic component. In particular I will describe the particle-injection and -acceleration mechanisms at work in the intra-cluster medium (ICM) and, at the same time, discuss the possibility to test current modellings of these phenomena with future radio, HXR, and gamma ray observatories.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The results of complex investigations of solar and interplanetary large-scale magnetic fields (LSMS) are set out. A rotation of sector structures of several types of LSMF was studied analysing evolution of their primary (main) rotation periods. It is confirmed the changing of Sun's rotation regime in the middle of century XX.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Galaxy-galaxy lensing (GGL) measures the 2-point cross-correlation between galaxies and mass in the universe. In this work we seek to generalise this effect by considering the third-order correlations between galaxies and mass: galaxy-galaxy-galaxy lensing. We introduce the higher-order cross-correlation functions and discuss their physical interpretation in terms of the halo model. We then demonstrate that measuring the lensing shear of background galaxies about foreground galaxy pairs, which we term galaxy-galaxy-galaxy lensing, provides a measure of the third-order cross functions. We note that current surveys in which detections of the cosmic shear 3-point correlation function have been reported should also be able to detect galaxy-galaxy-galaxy lensing. Indeed, we suggest that this effect may already have been detected in recent studies of GGL.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Bastille Day Event on July 14 2000, a major solar flare and a global coronal mass ejection (CME), is not a phenomenon of a single active region. Activation and eruption of a huge trans-equatorial filament is seen to precede the simultaneous filament eruption and flare in the source active region, AR9077, and the full halo-CME in the high corona. Evidence of reconfiguration of large-scale structures, manifested by SOHO EIT and Yohkoh SXT observations, is clearly seen. The large-scale magnetic composition related to the trans-equatorial filament and its sheared magnetic arcades appears to be the essential part of the CME parent magnetic structure. Estimations show that the filament-arcade system has enough magnetic helicityto account for the helicity carried by the related CMEs.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In the framework of the analytical theory of close encounters, and under suitable assumptions, we compute the size of the region in orbital elements space containing collisions solutions. In the linearized approximation in the semimajor axis/eccentricity plane the collision region is the interior of an ellipse. Examples are given from past cases of Near Earth Asteroids having the possibility of impacting our planet.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The current status of our knowledge of magnetic fields in A-type stars is reviewed with special emphasis on the progress achieved for “classical” Ap stars over the last four years. For those stars, the distribution of the strength of the field, its three-dimensional structure, and its relation with rotation and evolution are discussed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html