We have mapped, for the first time, the full velocity extent of the water maser emission in NGC 3079. Based on the analysis of the spectral-line maps, we propose a nearly edge-on, massive, thick, and flared disk for the geometric model of the inner parsec. The disk orbits a mass of $\sim2\times 10^6 M_{\odot}$ enclosed within 0.4 pc, most likely a supermassive black hole. The disk is most likely self-gravitating, clumpy, and supportive of star formation. The presence in our VLBI continuum images of an aging synchrotron component, which is not collinear with the previously imaged jet, might be suggestive of changes in jet orientation. The jet may coexist on pc-scales with a wide-angle outflow, that is related to the kpc-scale superbubble and that is inferred from the observation of dense molecular material at high latitudes above the disk.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the results of observations made over three weeks using the UCT CCD Photometer on the 0.75-m telescope at the South African Astronomical Observatory. Candidate long period roAp stars were identified from their positions on the H-R diagram and observed for a typical period of 4 hr to test for the existence of pulsations, with particular emphasis on pulsations with periods in excess of 15 min. Although 13 stars were successfully observed, none exhibited significant pulsations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Soft X-ray observations by Yohkoh SXT have revealed that transient brightenings of small coronal loops frequently occur in active regions. Their estimated energy is $10^{24} \sim 10^{28}$ ergs and non-thermal behaviors may be observed in the large member of the brightenings. They are considered as soft X-ray signatures of microflares observed in hard X-rays. Lower coronal temperature plasma (1-2MK) produced by Yohkoh transient brightenings is simultaneously observed in EUV wavelengths by TRACE and SoHO EIT/CDS. Moreover, EUV observations have shown a lot of tinier transient brightenings without accompanying SXT transient brightenings. Coordinated observations with photospheric observations show that the location of Yohkoh transient brightenings is well localized in active regions, i.e., in emerging flux regions, around well-developed sunspots, and in the coronal bundles connecting the leading plage to the following plage regions. In some Yohkoh events, small-scale emergence of magnetic flux is well associated with their occurrence, suggesting that emerging flux plays a key role in triggering transient energy release in the corona. This paper reviews multi-wavelength observations coordinated with Yohkoh SXT observations for investigating the nature of SXT transient brightenings (SXR microflares) and their associated emerging flux. Finally, Solar-B space observatory is briefly introduced as a next powerful tool for multi-wavelength investigations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present results of the analysis of spectroscopic time-series observations of the roAp star HD 24712 obtained at the phase of magnetic maximum. As in previous investigations of roAp stars we found that only lines of the rare-earth elements (REE) show RV pulsational variations. These pulsations in HD 24712 are characterised by gradual phase shifts between RV curves of different REE. The same pulsations of HD 24712 were observed in 2001, giving strong evidence for the stability of the pulsational mechanism in this star. NLTE calculations of Nd line depth formation in stratified atmosphere of HD 24712 allowed us to study the pulsational phase distribution with optical depth, providing strong evidence for a running wave, propagating outward with nearly constant RV amplitude.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigate the interplay between active nuclei and their surrounding ISM by interferometric radio continuum and mm line observations at high angular resolution and high sensitivity of a sample of active galaxies (e.g. NGC3718), carried out with MERLIN, EVN and the IRAM Plateau de Bure interferometer. They are part of an ongoing international study-NUGA (NUclei of GAlaxies)-about the nature, i.e. basically the fueling mechanisms, of nearby active galaxies. The mm line observations provide information about the distribution and kinematics of the molecular gas in these galaxies, which are regarded to be an important part of the matter feeding the central engine. We find a variety of molecular gas structures in our sample ranging from spirals, bars, warped disks, rings to asymmetric disks. The MERLIN/EVN measurements at 18 cm, as well as 6 cm, allow us to investigate the nature of the central engine itself. Also, the radio observations unveil extended structures on all observed angular scales (from VLA to MERLIN and EVN), like jets, diffuse components, as well as compact features. Moreover, the spectra are flat to steep, depending on the respective source components. The combination of the mm line and radio continuum results allow us to discuss possible interactions between the observed jets and the surrounding interstellar medium.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Magnetic coupling relates the energy sources below the photosphere to the structure and dynamics of the chromosphere and corona of the Sun. Multi-wavelength investigations of the solar activity provides the information needed to understand the acting physical mechanisms. Descriptions of magnetic coupling often start with force-free mathematical extrapolations of the photospheric magnetic field. Observations have revealed, however, perpendicular electric current sheets, reconnection and other locally non-force-free structures in chromosphere and corona. Obviously, the solar magnetic coupling includes dynamic forcing due to photospheric plasma motion. We developed a model which though it starts with force-free extrapolated observed photospheric magnetic field additionally takes into account the energy input due to the chromospheric neutral gas and plasma motion. We demonstrate the abilities of our model by applying it to SoHO multi-wavelength observations of an EUV bright point (BP).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The recent discovery of hidden non-axysimmetric and disk-like structures in bright Virgo dwarf elliptical and lenticular galaxies indicates that they may have late-type progenitors. Using high resolution N-body simulations we follow the evolution of disk galaxies within a $\Lambda\textrm{CDM}$ cluster simulated with $10^7$ particles where the hierarchical growth and galaxy harassment are modelled self-consistently. Most of the galaxies undergo significant morphological transformation, even at the outskirts of the cluster, and move through the Hubble sequence from disks to spheroidals. The time evolution of the simulated galaxies is compared with unsharp-masked images from the VLT and we compare the kinematics of our models with the latest high resolution spectroscopic studies from the Keck telescope. We will also discuss the properties of diffuse intra-cluster light formed by tidal debris stripped away from the infalling disks by gravitational interactions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The solar results from CORONAS-F satellite have been reviewed. The observations with the DIFOS multi-channel photometer in a broad spectral range from 350 to 1500 nm have allowed to determine the dependence of the relative amplitudes of p-modes of the global solar oscillations on the wavelength. The EUV observations in SPIRIT experiment have enabled the study of various manifestations of solar activity and high-temperature events on the Sun. The data from the flare instruments-gamma spectrometer HELICON, flare spectrometer IRIS, amplitude-time spectrometer AVS-F, and X-ray spectrometer RPS-1 have been used to analyze the hard emission from solar flares and to carry out the diagnostics of the solar flare plasma. The Solar Cosmic Ray Complex has investigated the solar flare effects in the Earth's environment. The UV emission variations during solar flares in the vicinity of the 120-nm wavelengh have been recorded and the relative variation amplitude has been determined.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A rapidly oscillating Ap star pulsates in high-order p-modes under the influence of a strong magnetic field. The strong field distorts spatially the angluar and the radial pulsation amplitude (eigenfunction). To study the effect of the magnetic field on the radiative excitation and the damping of p-modes, we performed a fully nonadiabatic analysis including the effect of a dipole magnetic field. A magnetic field always tends to stabilize low order p-modes. In the presence of a magnetic field stronger than $\sim 1{\rm kG}$, all $\delta$ Scuti type pulsations are stabilized. For high-order p-modes, on the other hand, the magnetic field enhances $\kappa$-mechanism excitation in some range of the field strength, depending on the pulsation frequency.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Modern kinematic diagnostics from high-S/N spectroscopy provide useful tests on the collisionless merger hypothesis for the formation of elliptical galaxies. Bender, Saglia & Gerhard (1994) show that the skewness of the line-of-sight velocity distributions (LOSVD) has opposite sign to the rotation velocity and follows a distinct pattern. Previous N-body experiments (Bendo & Barnes 2000, Naab & Burkert 2001) disagree as to whether the relation is reproduced by the models.

We present first results from an ongoing effort to explain the skewness properties of the LOSVD's of ellipticals. We use large N-body simulations of disk-disk galaxy mergers ($10^6$ particles), with mass ratios 1:1 and 3:1. Our 1:1 models fail to reproduce the H3 vs. $V/\sigma$ relation, in agreement with Naab & Burkert (2001). 3:1 mergers yield trends similar to the observations for large values of $V/\sigma$, but with overall lower H3 values in the models than in real galaxies. And we fail to reproduce high H3 values for low $V/\sigma$. So far, it is unclear whether the disagreement is related to the lack of rotation in the bulge components of our initial model galaxies, or to a more general shortcoming of dissipationless mergers to reproduce the properties of real ellipticals.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The intrinsic emission of obscured active galactic nuclei (AGN) cannot be measured directly, but the obscured examples uniquely allow determination of the physical conditions near the central engine on 10–100 pc scales. The reprocessed radiation that emerges at X-ray and infrared energies, in particular, reveals the distribution of the obscuring medium. In general, X-ray spectroscopy shows the total column density along the line of sight, and in extremely obscured (Compton thick) cases, the fluorescent iron Kα emission line is sensitive to viewing angle and covering fraction. Observed near- and mid-infrared spectra require an inhomogeneous distribution of material around the AGN, and they specifically depend on parameters such as the optical depth per obscuring cloud and the number of clouds along the line of sight. The total spatial extent of the obscuring region determines the shape of the far-infrared spectrum.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Moreton waves are flare-associated waves observed to propagate across the solar disk in H$\alpha$, especially in the wing of H$\alpha$. The Flare Monitoring Telescope at Hida Observatory of Kyoto University observed 12 events associated with flare waves (i.e., Moreton waves and/or filament oscillations) in H$\alpha$ from 1997 to 2002. We review our studies of Moreton waves based on these observations;

1. relation between EIT wave and Moreton wave (Eto et al. 2002),

2. simultaneous observation with X-ray wave (Narukage et al. 2002),

3. three dimensional structure of flare-associated wave (Narukage et al. 2004),

4. relation between Moreton waves and filament eruptions.

Ab-initio modeling of galaxy formation is becoming ever more detailed and is including ever more physical processes in a bid to describe the process of galaxy formation more realistically. We will describe some recent advances and applications of the semi-analytic model of galaxy formation, GALFORM. In particular, we will describe a preliminary study of the effects of environment on galaxy morphology in a $z=0.4$ cluster.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Spectroscopic mode identification techiques, which monitor intensity variations across an absorption line, provide the possibility of determining the quantum numbers l and m, the inclination and the intrinsic pulsation amplitude of a star. Of course, the uncertainties of the mode identification are dependent on the quality of the observations and the identification method applied. We have focused on the Pixel-by-pixel method/Direct line profile fitting (Mantegazza 2000) and the Moment method (Balona 1987, Briquet & Aerts 2003) for pinpointing mode parameters and tested the impact of various observational effects and stellar properties on the identification.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present results from an imaging and spectroscopic study of the dust properties of Seyfert galaxies in the 1-10 μm range. The data are compared to state of the art models of torus emission to constrain geometrical and physical properties of the obscuring medium.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

VLA observations of selected FR-II jets (3C208, 3C352, 3C434, 3C9 and 3C14) between 5 and 15 GHz are used to derive astrophysical properties in the jets of these radio sources. We interpret the results as giving support for unifying schemes of radio galaxies and quasars. We have also determined the Faraday rotation for jets and counter-jet sides. Rotation measures are used to constrain the internal density and mach numbers of the jets, obtaining values similar to those of quasar jets but higher than those of radio galaxies. The radio brightness can be explained by doppler boosting of the synchrotron radiation, giving evidence for orientation effects as an origin for the Laing-Garrington effect.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigate environmental effects on evolution of bright cluster galaxies in a $\Lambda$-dominated cold dark matter universe using a combination of dissipationless $N$-body simulations and a semi-analytic galaxy formation model. We incorporate effects of ram-pressure stripping (RPS) and minor merger-induced small starburst (minor burst) into our model. By considering minor burst, the observed morphology-radius relation is successfully reproduced. When we do not consider minor burst, the RPS hardly increases the intermediate B/T population. In addition, the RPS and minor burst are not important for colours or star formation rates of galaxies in the cluster core if star formation time-scale is properly chosen, because the star formation is sufficiently suppressed by consumption of the cold gas. We also find that SF in bulge-dominated galaxies is mainly terminated by starburst induced by major mergers in all environments.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Period04, a reworked and extended version of Period98 (Sperl 1998) and PERIOD/PERDET (Breger 1990), is a new software package especially dedicated to the statistical analysis of large astronomical data sets containing gaps. It offers tools to extract the individual frequencies from the multiperiodic content of time series and provides a flexible interface to perform multiple-frequency fits. A review of the functions of Period04 is given.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The quantitative relation between the brightness of the coronal green line 530.5 nm Fe XIV and the magnetic field strength is considered over the 1977-2001 period. It is found that the correlation coefficients between these two parameters calculated separately inside and outside the sunspot formation zone $\pm 30^{\circ}$ have cyclic variation and occur in anti-phase. This suggests different mechanisms of formation of the corona in the fields of small, medium, and large scales. These results can be used for quantitative verification of the corona heating models.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Standard models of galaxy formation make specific predictions for how galaxy properties depend on environment. These predictions follow from the assumption that galaxy properties are entirely determined by the formation histories of the halos which host them, and that the distribution of dark halo masses is skewed towards large masses in dense regions. We describe two tests of this assumption which can be made with currently available data.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html