First results from the AGN-Heidelberg program aimed at spatially resolving the central pc region of the closest Active Galactic Nuclei are presented. The core region of prototype active nuclei are clearly unveiled at IR waves and at distances from the nucleus – few pc- where circumnuclear starforming regions appear not to be present. Within that perspective, classical active nuclei as Circinus and NGC 1097, reveal with unprecedented detail clear channels of material being driven to the core whereas others as Centaurus A and NGC 5506, show a “clean” core environment. At the very center, a central compact region of ∼2 pc scale is resolved in Circinus but not in the other cases challenging thus the universal presence of the putative obscuring torus.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The December 1639 transit of Venus was only seen and recorded in Much Hoole and Salford, Lancashire, England. It was visible, however, from all over Italy, France, Spain and Portugal. But no one was looking. This paper suggests reasons why.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We consider the Solar Cycle - the variation in any solar, heliospheric or cosmic ray parameter, related to the well-known 22-year dynamo-like process on the Sun - and discuss how it is influenced by the inner (the transformation of the solar activity in the basement of the heliosphere) and the external (the interaction between the solar and interstellar winds) factors. The corresponding approaches to the description of the long-term variations (the Solar Cycle, secular and longer ones) in the galactic cosmic ray intensity are outlined.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The structure of the universe is believed to have formed by clustering hierarchically from small to large scales. Much of this evolution occurs very slowly but at a few special times more rapid, violent activity may occur as major subunits collide at high velocities. The Abell 2125 complex ($z=0.247$) appears to be undergoing such an event as shown by modeling of the optical velocity field and by the detection with the VLA of an unusually large number of associated radio active galaxies. We present an 80 ksec Chandra imaging of Abell 2125, together with extensive complementary multi-wavelength data. We show direct evidence for galaxy transformation and destruction during the cluster formation. The Chandra data unambiguously separate the X-ray contributions from discrete sources and large-scale diffuse gas in the Abell 2125 complex, which consists of various merging clusters/groups of galaxies and low-surface brightness emission. This enables us to study processes affecting galaxy evolution during this special time from scales of Mpc down to a few kpc. The overall level of activity plus the special time for the cluster-cluster merger suggests that an important phase of galaxy evolution can take place during such events.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using an homogeneous sample of $v\sin i$ values for A-type main sequence stars (Royer et al. 2002), the equatorial velocity ($v$) distributions are determined as function of spectral class, from B9 to F2. The chemically peculiar and binary stars are discarded. These distributions of “normal” stars are discussed in terms of stellar formation and evolution, in particular the remaining bimodality observed for the earliest spectral types of the sample. We show that late B and early A-type main-sequence stars have genuine bimodal distributions of true equatorial rotational velocities probably due to the phenomena of angular momentum loss and of redistribution the star underwent before reaching the main sequence. A striking lack of slow rotators is noticed among intermediate and late A-type stars. The bimodal-like shape of their true equatorial rotational velocity distributions could be due to evolutionary effects.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

From observations of the Sun as a star made at Kitt Peak it is known that MnI 539.5 nm line exhibits unusually big (for a photospheric line) variations during a solar activity cycle. Doyle et al. 2001 suggested that it is because of optical pumping. This work aims particularly to check this hypothesis with help of observations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The orbital evolution of planetary systems similar to our Solar one represents one of the most important problems of Celestial Mechanics. In the present work we use Jacobian coordinates, introduce two systems of osculating elements, construct the Hamiltonian expansions in Poisson series for all the elements for the planetary three-body problem (including the problem Sun–Jupiter–Saturn). Further we construct the averaged Hamiltonian by the Hori–Deprit method with accuracy up to second order with respect to the small parameter, the generating function, the change of variables formulae, and the right-hand sides of the averaged equations. The averaged equations for the Sun–Jupiter–Saturn system are integrated numerically over a time span of 10 Gyr. The Liapunov Time turns out to be 14 Myr (Jupiter) and 10 Myr (Saturn).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present Chandra observations of the nuclear region of nearby inactive galaxies. The sample is selected based on the absence or weakness of optical emission lines in the nucleus. X-ray nuclei are detected in four out of six galaxies. This result, along with previous observations, suggests that more than half of galaxies, for which no evidence for nuclear activity is known, possess an ultra-low-luminosity “active” nucleus. X-ray emission from hot gas is detected in at least four galaxies. We estimate the Bondi accretion rate from the gas density, temperature, and central black hole mass and suggest that the accretion luminosity is not simply determined by the Bondi rate.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Cluster mergings are expected to have an influence on the radio emission of the galaxy population. We present the results of a deep radio survey in the A3558 complex in the central region of the Shapley Concentration, in order to further explore our hypothesis of a dependence of the radio luminosity function on the age of the merging.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

During the second half of the nineteenth century Brazilian astronomers participated in the observations of transit of Venus. In 1874 a Brazilian astronomer, Francisco Antônio de Almeida was sent by the Imperial Observatory to Nagasaki to use the “photographic revolver” invented by Jules Janssen. In 1882 three missions were sent by the Imperial Observatory (Brazil) to observe the transit in St Thomas (Antilles), Punta Arenas (Chile) and Olinda (Brazil). The value of the solar parallax obtained by the Brazilian Commission, led by Luís Cruls, was 8.$\rlap ^{\prime\prime}$808, representing at that time one of the most precise values.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We consider the CMB bispectrum signal induced by structure formation through the correlation between the Integrated Sachs-Wolfe and the weak lensing effect. We investigate how the bispectrum knowledge can improve our knowledge of the most important cosmological parameters, focusing on the dark energy ones. The bispectrum signal arises at intermediate redshifts, being null at present and infinity, and is characterized by a large scale regime (dominated by linear dynamics of cosmological perturbation) and a small scale one (dominated by density perturbations in a non-linear regime); on the other hand, the effect induced by dark energy on the power spectrum is mostly geometrical and imprinted at redshift close to the present. Because of this, the knowledge of power spectrum and bispectrum yield two complementary informations at very different cosmological epochs, particularly suitable to extract informations about the onset of the cosmic acceleration and dark energy properties that provide it. In order to quantify how much the bispectrum can help the power spectrum in constraining the dark energy parameters, we choose a fiducial model on a three-dimensional space including the following dark energy parameters: dark energy density $\Omega_V$; dark energy equation of state today $w_0$ and dark energy equation of state in the past $w_\infty$ ($w_\infty - w_0$ is related to the first derivative of equation of state). Then we simulate a likelihood analysis showing how contour levels become narrower when bispectrum is included. Preliminary results suggest a consistent improvement on the estimation of dark energy abundance and on dynamical properties of the equation of state. This indicates that the knowledge of the bispectrum in future high resolution and high sensitivity CMB observations could yield a substantial improvement with respect to the traditional analysis based on the power spectrum only.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The time and location of magnetic reconnection are indicated by radio (Nobeyama Radio Heliograph and Polarimeters, Hiraiso and Chinese radio spectrographs) and multi-wavelength (SOHO and TRACE satellites) data in a selected flare-CME event on April 21, 2002. Two hour radio burst started at high frequencies (maximum around 10 GHz). After that, a radio ejection at 17 GHz from one foot point was coincident with the expanded flare and post-flare loops. The reversal of polarization sense at the radio loop-top is associated with the strong coherent emissions around 2 GHz, which should be located above the loop-top at 17/34 GHz. The radio ejection and coherent emissions are also associated with a pair of moving type $I\!V$ bursts at 0.2-2 GHz from high to low frequencies and 2.6-3.8 GHz from low to high frequencies, respectively. High time resolution (8 ms) data show three components of the frequency drifts at 2.6-3.8 GHz: very slow (5 MHz/s) of moving type $I\!V$, slow (50 MHz/s) of zebra strips, and fast (several GHz/s) of type $I\!I\!I$, which may represent respectively the speeds of flare loop or current sheet, outflows, and energetic electrons from the reconnection site.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The Astronomical Unit is one of the most basic units of astronomy: the scale of the solar system. Yet its long and colorful history is sprinkled liberally with incorrect descriptions and mis-quoted definitions – today as much as ever. Over the last half century, the accuracy of the au determinations has improved dramatically: optical (triangulation) methods have given way to modern electronic observations, high-speed computers, and dedicated efforts to improve planetary ephemerides. Typical uncertainties in the value of the au have decreased from many tens of thousands of kilometers to the present level of only a few meters. With the solar system providing a very clean, undisturbed dynamical model, the ephemerides have been used for a variety of exotic physical tests: alternative theories of gravitation, $d({\rm G})/dt$, $d({\rm au})/dt$, etc. In the beginning of this modern era, the author happened to be a witness to a couple of rather key events; more lately, a participant. A couple of these personal experiences are related.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We show that Massive Black Holes of AGNs follow the same approximately linear relation with the luminosity of the host spheroid (bulge) found in normal (quiescent) galaxies, with the black hole mass being 0.002 that of the bulge. We also demonstrate that Narrow line AGNs seem to have a significantly lower Mbh/Lbulge ratio, which implies a new strong correlation between Mbh/Lbulge and the width of the broad emission lines of AGNs (Wandel 2002). Combining existing data, new observations and extrapolation schemes based on the Faber-Jackson relation, the relation between the BH mass and the stellar velocity dispersion in the host bulge of AGNs is constructed. It too agrees with the relation found in quiescent galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The new SOHO/MDI data (1996-2003) reveal an interesting result that the total polar magnetic fluxes do not vary significantly during the polar magnetic field reversals in both hemispheres, while the positive and negative parts of the total fluxes do change.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The solar radio bursts and accompanying fine structures recorded by spectrometers at Huairou, Beijing during 1999-2003 are presented. The spectrometers are with high temporal (5-10 ms) and spectral (4-20 MHz) resolutions. We found 91 radio burst events that occurred within half hour of the onset of the CME events which cause solar energetic particle events. The associations of radio fine structures with CME events are discussed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We are witnessing tremendous progress in the nascent multidisciplinary field of astrobiology, encompassing the origin and evolution of life in the cosmic context. One of the key concepts recently introduced in this field is the Galactic Habitable Zone (GHZ): an interval of galactocentric distances convenient for formation of stars possessing habitable planets. The boundaries of the GHZ are still poorly understood, however. Here we present a comparative analysis of various proposals for the mechanisms determining the GHZ boundaries, as well as different numerical values obtained. When joined with the models of Galactic stellar distribution, this gives us a better handle on the number of potential life-bearing sites.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the preliminary results of 235 MHz, 327 MHz and 610 MHz observations of the galaxy cluster A3562 in the core of the Shapley Concentration (SC). The purpose of these observations, carried out with the Giant Metrewave Radio Telescope (GMRT, Pune, India) was to study the radio halo located at the centre of A3562 and determine the shape of its radio spectrum at low frequencies, in order to understand the origin of this source. In the framework of the re–acceleration model, the preliminary analysis of the halo spectrum suggests that we are observing a young source (few $10^8$ yrs) at the beginning of the re–acceleration phase.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

PISKUNOV: I would like to start this discussion with evolutionary aspects. There are a few recent developments both observational and theoretical. So, some might disagree and others might agree that there are many things happening concerning the pre-Main sequence evolution of early A type and Ap stars and that is what makes them different. Would anybody like to comment?To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the theory of weak gravitational lensing in cosmologies with generalized gravity, described in the Lagrangian by a generic function depending on the Ricci scalar and a non-minimally coupled scalar field.

We work out the generalized Poisson equations relating the dynamics of the fluctuating components to the two gauge invariant scalar gravitational potentials, fixing the new contributions from the modified background expansion and fluctuations.

We show how the lensing observables are affected by the cosmic expansion as well as by the presence of the anisotropic stress, which is non-null at the linear level both in scalar-tensor gravity and in theories where the gravitational Lagrangian term features a non-minimal dependence on the Ricci scalar. We derive the generalized expressions for the convergence power spectrum, and illustrate phenomenologically the new effects in Extended Quintessence scenarios, where the scalar field coupled to gravity plays the role of the dark energy.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html