We present XMM-Newton observations of the galaxy cluster Abell 514. This cluster shows a very complex X-ray morphology. Radio observations show that there are six radio sources located inside the cluster. This makes it possible to determine the magnetic field strength using the Faraday rotation method. This cluster is an example for the hierarchical growth of structure and a very interesting object for studying the correlation between magnetic field strength and X-ray properties.

By using 2D simulations, we examine the generation of dense cores and substructures by magnetosonic waves. We find that the excitation of slow-mode waves by fast-mode waves produces these high-density structures.

We discuss a long-term solution for the insolation quantities of the Earth.

We present the preliminary detection of a stellar halo in the nearby, edge-on galaxy, NGC 4244. Using data from the Hubble Space Telescope's Advanced Camera for Surveys (HST/ACS), we have examined number counts of red giant branch (RGB) stars along the minor axis of the galaxy out to 10 kpc, with a limiting surface brightness of μR ∼ 31 mag/arcsec2. At distances more than 2.5 kpc above the disk, a second stellar component is clearly visible. This component is well fit by either an exponential or a power law. The best-fit exponential scale height is similar to the scale length of the galaxy disk, suggesting that we are indeed detecting a halo component. Furthermore, the color of the RGB stars above 2.5 kpc are significantly bluer than those in the disk, suggesting a more metal-poor population. Outside the local group, this finding represents one of the first detections of a resolved stellar halo in a spiral galaxy.

We discuss aspects of using the P03 precession model.

We examine the galaxy luminosity functions (LFs) in the Hydra I cluster (Abell 1060) at z = 0.0126, for which very faint galaxies (down to M ~ −10) have not been surveyed yet. We conclude that the total LF has a slightly steep slope (α ~ −1.6) at −20 < M < −10 in the B- and RC-bands. The numbers of galaxies at the faint end (M ≳ −14) differ in between the cluster center and the outskirts slightly. We divide the Hydra member galaxies into red/blue galaxies and find that the shape of LFs in the faint magnitude range is determined by red dwarf galaxies.

We analyse the star-forming (SF) properties of the two brightest galaxies in the IC 65 group of galaxies and that of the four newly detected dwarf galaxies in the area of the group. The dIrr galaxies around the IC 65 contain a number of HII regions which show a range of stellar ages, and provide an evidence of propagating SF. The two brightest group galaxies show SF rates of ∼ 1 − 2 M⊙ yr−1, and can fuel the current SF level for about the next 3 – 7 Gyr.

In order to detect variable stars in the well known star forming region, the Orion Nebula Cluster, a series of 22 exposures taken from November 1996 to October 1998, using the ESO 100/152cm Schmidt telescope, covering a field of 5° × 5° was analyzed. The films (Kodak Tech-Pan 4415 emulsions, effective spectral range from ~630 nm to 690 nm) were digitized by the SuperCOSMOS machine, the measurements calibrated to the R magnitude of the USNO B1.0 catalogue and differential photometry was performed throughout the whole field. In the process, a set of 260 stars that remained constant in the 22 films and were well distributed over the field was selected and used as comparison stars for the differential photometry of all the other stars in the field. Diverse statistical studies were performed in order to characterize the type and degree of variability of the objects. The 22 films, all exposed for 30 minutes each, were stacked together at our request by the SuperCOSMOS team, producing perhaps the deepest wide field image of M42 ever taken.

This database (>150 000 objects, mostly stars and ~2% galaxies) is going to be used as a starting point for the Variable Young Stellar Object Survey (VYSOS) project, which consists of 2 fully automated robotic telescopes of 41cm each, one installed on Mauna Loa (Hawaii, USA) and the other at Cerro Armazones (Chile), both using the Pan STARRS set of photometric filters. We discovered thousands of new variable stars within the 5° × 5° region studied. We have variability statistics for all objects and are classifying the variable stars according to the variability type and amplitude. We intend to make this database available via the WEB.

Our goal is to study relatively quiescent dense gas cores, isolated from disruptive stars, to understand the initial conditions of massive star formation. Determining their mass, size, dynamical status, and core mass distribution is a starting point to understand the mechanisms for formation, collapse, and the origin of their IMF. We obtained CSO 350 μm, images of quiescent regions in Orion and detected 51 resolved or nearly resolved molecular cores with masses ranging from 0.1 M to 46 M (Li et al. 2006). The mean mass is 9.8 M, which is one order of magnitude higher than that of the resolved cores in low mass star forming regions, such as Taurus. Our sample includes largely thermally unstable cores, which implies that the cores are supported neither by thermal pressure nor by turbulence, and are probably supercritical. They are likely precursors of protostars.

The combination of stellar population synthesis models and photoionization models allows a better understanding of the spectral features of HII regions and HII galaxies. In this work we show that sampling effects in the initial mass function (IMF) are very important in the low cluster mass case. To this aim, we compute photoionization models ionized by realistic clusters made up of various combinations of individual stars and clusters made up with a synthesis model. We discuss the differences in the position on diagnostic diagrams and their implications.

We discuss aspects of long-periodic precession parametrization.

We investigate the morphologies and velocity fields of spiral galaxies in distant clusters (z ~ 0.5) focussing on signatures from interactions. Structural parameters and peculiarities are determined with HST/ACS images. To derive the internal kinematics and rotation curves we have performed 3D–spectroscopy allowing the construction of the full velocity field for each galaxy. Combining both approaches, transformation mechanisms are revealed that affect not only the stellar populations but also the mass distribution. The observations are supported by N-body/SPH simulations of different interaction processes.

This paper reviews the star formation history of the Universe, from the first stars to the current day, with emphasis on the critical analysis of the techniques that have been used to determine it, especially considering the role of dust. We consider the first population of stars, the Population III stars, were formed at redshifts ranging as high as z ~ 60, the formation of the Globular Clusters, the main epoch of galaxy formation. In the sub-mm galaxies and high-redshift radio galaxies the collapse of massive galaxies was surprisingly rapid, and that the growth of super-massive black holes at their centers provides the energy input to eject the galactic interstellar medium while at the same time precipitating a final burst of star formation and the ejection of their ISM so that the subsequent evolution of these galaxies is passive.

We present a new method for measuring the recent star formation history (SFH) of galaxies from their 4000Å break and Balmer absorption line strength. By making use of the whole 3750-4150Å spectral region, the method achieves a higher signal-to-noise ratio than traditional indices. The new technique is ideally suited to finding evidence for weak or old starbursts in good quality spectra, or studying post-starburst galaxies at high redshift. On application to massive, bulge dominated galaxies in the SDSS, we find clear correlations between the recent star formation history of bulges and the properties of the AGN.

We discuss models for high-precision spacecraft and planetary and lunar ephemerides.

We have used the FLAMES multi-integral field unit system of the European Southern Observatory (VLT) centered on the cluster MS0451.6-0305 at z = 0.5386 to obtain the spatially resolved kinematics of the cluster members. The spectral data are supported by HST/ACS images that provide immediate morphological information of the cluster galaxies. The relevant structural parameters such as inclination, size, and orientation derived from optical high angular resolution images are compared with those derived from the kinematics. Our final goals are: 1. to derive the Tully-Fisher relation for cluster galaxies with regular kinematics. 2. to obtain the dynamical masses from resolved kinematics and stellar masses from optical images to be compared with local measurements.

Chemodynamical disc galaxy simulations calibrated with stellar populations synthesis models allow to build mock multi-wavelength images from numerical simulations. The morphological evolution of the mass and colour distributions can thus be simultaneously followed. We present the evolution of the stellar disc and bar structural parameters and summarize a number of important results we got in the recent past.

We discuss relativistic aspects of Earth's roration

The importance of the star-gas cycle for the evolution of galaxies is discussed. We describe three different ways of stellar mass loss: a) the gas return from low and intermediate mass stars, b) the stellar winds from OB associations; c) the superwinds from superstar clusters.

The study of dusty discs is an important topic in astrophysics, as they seem to be abundant around different objects and are related to different phenomena. In this poster we present 3D radiative transfer simulations of T Tauri type discs with an inhomogeneous dust distribution to investigate the effect of a clumpy medium on the dust temperature distribution. Our initial results indicate that the structure of the dust temperature distribution is rather insensitive to the structure of the ISM, but nevertheless we find a clear and systematic dependence on the parameters describing the structure of the clumpiness of the dust medium.