We study the global effects of the clouds-SN shock wave interactions on the mixing of the gas in Starburst galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The renew non-hydrostatic model of electron density, temperature and velocity distribution with height in coronal hole (CH) is build. The presented model is based on the measurements of magnetic field in CH with RATAN-600 observations and on the assumption about equality of magnetic and kinetic energy of upward plasma flows in CH at heights of generation of radio emission in wavelength range 20–30 cm. To construct this model the observational spectrum of brightness temperatures of CH in wavelength range 2–30 cm is used. The first results of modeling are presented.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The direct comparison of observations to numerical hydro-N-body simulations, although simple in principle, is not always trivial because of possible artificial effects produced by the instrument response and by instrumental and sky background. To overcome this problem we build the software package X-MAS (X-ray MAp Simulator) devoted to simulate X-ray observations of galaxy clusters obtained from hydro-N-body simulations.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using data from the new EBASIM spectrograph at the 2.1-m telescope of the Complejo Astronómico El Leoncito (CASLEO), two rather sharp-lined B stars 5 Aqr (=HD 198667, B9 III) and 30 Peg (=HD 211924, B5 IV) are being studied. The measurements are compared with those from the coudé spectrograph of the 1.22-m telescope of the Dominion Astrophysical Observatory (DAO). The equivalent width scales of the EBASIM and the DAO data are similar. As we found that the line profiles of 30 Peg are variable, we are trying to determine whether this star is a slowly pulsating B star. 5 Aqr has abundances close to those of the Sun.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The time-averaged images of the solar granulation exhibit a slower decrease in contrast with the averaging time than do time-averaged images of numerically simulated granulation and time-averaged random fields with some parameters typical of granulation. This confirms the hints for long-lived structures in the granulation pattern.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a semi-analytic model able to trace the thermalisation history of the ISM in a Starburst region and determine the SN heating efficiency evolution.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyse statistically the infall of mass onto clusters in $\Lambda$-CDM numerical simulations. Also, we consider numerical simulations which include galaxy formation through semi-analytical models to compare the expected infall of mass and galaxies. We find the most probable values at $V \sim 300-400$ km/s and a significant tail of large infall velocities ($V > 1000$ km/s). The flow onto cluster is more pronounced for high local density regions. Mass and galaxies behave similarly although with a slightly lower amplitude.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using a 2.5-D, time-dependent ideal MHD model in spherical coordinates, we carry out a numerical study of the equilibrium properties of coronal magnetic flux ropes in a quadrupolar background magnetic field. For such a flux rope system, a catastrophic occurs: the flux rope is detached from the photosphere and jumps to a finite altitude with a vertical current sheet below. There is a transversal current sheet formed above the rope, and the whole system stays in quasi-equilibrium. We argue that the additional Lorentz force provided by the transversal current sheet on the flux rope plays an important role in keeping the system in quasi-equilibrium in the corona.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyze long slit spectroscopy of NGC 1052, the third brightest member of a group of eleven galaxies. This elliptical is a typical LINER with a stellar rotating disk. We have found a strong negative radial gradient of the abundance ratio Mg/Fe, which suggests an enhancement of α-elements particulary towards the nuclear region, and higher metallicity and age at the galactic nucleus too. We have measured the Lick line-strength indices along the major axis of the galaxy. This information, together with single-aged stellar population models of Thomas et al. (2003), was used to determine the star formation history of NGC 1052.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the first center-to-limb G-band images synthesized from high resolution simulations of solar magneto-convection. Towards the limb the simulations show “hilly” granulation with dark bands on the far side, bright granulation walls and striated faculae, similar to observations. At disk center G-band bright points are flanked by dark lanes. The increased brightness in magnetic elements is due to their lower density compared with the surrounding intergranular medium. One thus sees deeper layers where the temperature is higher. At a given geometric height, the magnetic elements are cooler than the surrounding medium. In the G-band, the contrast is further increased by the destruction of CH in the low density magnetic elements. The optical depth unity surface is very corrugated. Bright granules have their continuum optical depth unity 80 km above the mean surface, the magnetic elements 200-300 km below. The horizontal temperature gradient is especially large next to flux concentrations. When viewed at an angle, the deep magnetic elements optical surface is hidden by the granules and the bright points are no longer visible, except where the “magnetic valleys” are aligned with the line of sight. Towards the limb, the low density in the strong magnetic elements causes unit line-of-sight optical depth to occur deeper in the granule walls behind than for rays not going through magnetic elements and variations in the field strength produce a striated appearance in the bright granule walls.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Based on the dynamics of charged particles in plasma with the two-fluid description, the equation for magnetic field generation and maintenance is derived. The nature of magnetic field in cosmic plasma and the generation can be understood from the equation. The ions and electrons are considered as two independent fluids with the collision connected. Due to the different viscosity between ions and electrons, there will be a velocity difference in ions and electrons. This causes a current in the plasma and generates magnetic field. IN the plasma system, the differential velocities and the viscous forces of the electrons are the source of magnetic field.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The stellar winds of A supergiants can have a significant influence on their emergent spectra. Here we present the hydrogen line profiles of a model based on the stellar parameters of HD 12953. The radiative transfer equation is solved in two dimensions in axial symmetry. We do not include the velocity field by the Sobolev approximation, but in detail using the Lorentz transformation. This allows us to correctly include the stellar wind, since the velocity gradients in A supergiants are too small for the Sobolev approximation to be valid.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this paper, we revisit the constraints obtained by several authors (Reichart et al. 1999; Eke et al. 1998; Henry 2000) on the estimated values of $\Omega_{\rm m}$, $n$ and $\sigma_8$ in the light of recent theoretical developments: 1) new theoretical mass functions (Sheth & Tormen 1999, Sheth, Mo & Tormen 2001, Del Popolo 2002b); 2) a more accurate mass-temperature relation, also determined for arbitrary $\Omega_{\rm m}$ and $\Omega_{\rm \Lambda}$ (Del Popolo 2002a).

Firstly, using the quoted improvements, we re-derive an expression for the X-ray Luminosity Function (XLF), similarly to Reichart et al. (1999), and then we get some constraints to $\Omega_{\rm m}$ and $n$, by using the ROSAT BCS and EMSS samples and maximum-likelihood analysis. Then we re-derive the X-ray Temperature Function (XTF), similarly to Henry (2000), re-obtaining the constraints on $\Omega_{\rm m}$, $n$, $\sigma_8$. Both in the case of the XLF and XTF, the changes in the mass function and M-T relation produces an increase in $\Omega_{\rm m}$ of $\simeq 20\%$ and similar results in $\sigma_8$ and $n$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We studied the line-of-sight (LOS) velocity field at the photospheric and chromospheric levels in the $H_{\alpha}$-loops in the course of the development of the bright flare. The spectra and filtergrams were acquired with the solar telescope ATsU-26 at the Terskol Peak Observatory. Time variations of the LOS velocities at loop tops and bases were compared to the $H_{\alpha}$ and hard X-ray fluctuations. The intensity variations and $H_{\alpha}$-filtergrams are evidence that elementary X-ray spikes are associated with consecutive disturbances of $H_{\alpha}$-loops in the arcade. The $H_{\alpha}$ intensities and velocities at the loop bases are much higher than at the tops. Different mechanisms can be efficient at the early stages of elementary X-ray spikes and at their maxima: ascent of photospheric matter at loop bases was recorded only when the $H_{\alpha}$ and hard X-ray intensities were minimum, and the intensity maxima were accompanied by descending motions of the photospheric plasma.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We carried out a spectroscopic survey of a sample of 59 Seyfert nuclei (observed both in the northern and in the southern hemisphere) around the stellar absorption lines of Calcium II at 8498.02, 8542.09 and 8662.14 Å (CaT). Our main goal is to determine their stellar velocity dispersions. These measurements, along with photometric information, will allow us to obtain the M/L ratio, useful to determine the nature of the ∼33% of “ambiguous” Seyfert 2.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The outskirts of clusters are dynamically complex regions populated by galaxies falling into the cluster potential for the first time as well as some which have already visited the cluster core. Addressing the properties of galaxies in these transition regions requires the integration of cluster dynamics, an understanding of environmental influences on galaxies at both high and low densities and hierarchical scenarios of cluster formation and growth. In this review I describe some recent observational results on galaxies in the outskirts of clusters, and the evolution of galaxies in clusters as a function of local density and radius.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Very high-quality, high-resolution optical CCD and photographic spectra of Vega reveal interstellar components in many spectra lines. The presence of these interstellar features suggests that detailed studies of such bright stars carried out with superb new data now available must take careful account of such contaminants in both abundance determinations and line profile fitting. Analyses of the interstellar features themselves can contribute to the general knowledge of the local ISM, an area previously largely limited to UV observations obtained by space facilties.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

SCHWENN: About the spiral pattern in the U.Michigan animation: We saw such unwinding spirals. Question: what are they?To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigate the relation between the asymptotic circular velocity, $V_{\rm circ}$, and the central stellar velocity dispersion, $\sigma_{\rm c}$, in galaxies. We consider a new sample of high surface brightness spiral galaxies (HSB), low surface brightness spiral galaxies (LSB), and elliptical galaxies with HI-based $V_{\rm circ}$ measurements. We find that: 1) elliptical galaxies with HI measurements fit well within the relation; 2) a linear law can reproduce the data as well as a power law (used in previous works) even for galaxies with $\sigma_{\rm c} \lt 70$ km/s; 3) LSB galaxies, considered for the first time with this respect, seem to behave differently, showing either larger $V_{\rm circ}$ values or smaller $\sigma_{\rm c}$ values.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have started an analysis of the sharp-lined superficially normal A3IVp star 95 Leo. We are using $2.4 \AA \mathrm {mm}^{-1}$ spectrograms covering $\lambda\lambda 3830-4934$ obtained with the 1.22-m telescope of the Dominion Astrophysical Observatory using CCD detectors. Their mean signal-to-noise ratios are $\ge\,200$. The spectrograms are rectified and measured with the interactive computer graphics program REDUCE of Graham Hill and his associates. In measuring the spectrum with the VLINE routine, we use the fixed parameter feature to deconvolute metallic line blends and to measure weak lines. Effective temperature and surface gravity estimates based on spectrophotometry and H$\gamma$ profile fitting were given in the literature as 8300 K and 3.65, respectively.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html