The Galactic center supermassive black hole is surrounded by orbiting clouds of gas. These clumps of gas may collide with each other, losing angular momentum and plunging towards the center. Observations of X-ray reflection from molecular clouds surrounding the Galactic center show evidence for enhanced activity of Sagittarius A* during the past few hundred years. These observations enable us to place constraints on the nature of past accretion events responsible for this enhanced activity. We model the source intrinsic luminosity of Sgr A* using multiple accretion events occurring at various moments in time, characterized by a range of angular momentum We also applied our scheme to the case of G2 cloud in the Galactic center.

The Tautenburg Exoplanet Search Telescope (TEST) is a robotic telescope system. The telescope uses a folded Schmidt Camera with a 300mm main mirror. The focal length is 940mm and it gives a 2.2° × 2.2° field of view. Dome, mount, and CCD cameras are controlled by a software bundle made by Software Bisque. The automation of the telescope includes selection of the night observing program from a given framework, taking darks and skyflats, field identification, guiding, data taking, and archiving. For the search for transiting exoplanets and variable stars an automated psf photometry based on IRAF and a lightcurve analysis based on ESO-Midas are conducted. The images and the results are managed using a PostgreSQL database.

Several examples of observational evidence of possible variations of geometrical and physical characteristics of the Broad Line Regions (BLR) of AGN on the time-scale of years are listed. Cases of accretion disk size variations and variable input of jets in BLR formation are presented.

The star HD 51844 was observed in the CoRoT LRa02 as a target in the seismology field, which turned out to be an SB2 system. The 117-day light curve revealed δ Scuti pulsations in the range of 6 to 15 d−1 where four frequencies have amplitudes larger than 1.4 mmag, and a rich frequency spectrum with amplitudes lower than 0.6 mmag. Additionally, the light curve exhibits a 3-mmag brightening event recurring every 33.5 days with a duration of about 5 days. The radial velocities from spectroscopy confirmed that the star is an eccentric binary system with nearly identical masses and physical parameters. The brightening event in the light curve coincides with the maximum radial-velocity separation showing that the brightening is in fact caused by tidal distortion and/or reflected light. One component displays large line-profile variations, while the other does not show significant variation. The frequency analysis revealed a quintuplet structure of the four highest-amplitude frequencies, which is due to the orbital motion of the pulsating star.

This conference is concerned with the very high resolution imaging of cosmic sources in many parts of the electromagnetic spectrum. Various techniques are now available and the equipment is often automated and highly sophisticated but the term ‘very high angular resolution’ is comparative. Many of the problems existed over forty years ago when the best resolving power was about half a degree and the two major radio ‘stars’ appeared to be point sources. Very high resolution imaging in those days was the struggle to reach one minute of arc and Hanbury Brown had set his sights on considerably better than one second of arc with the concept of the intensity interferometer. The dream was to achieve a resolving power comparable to that of optical telescopes.

Several meteorite types, distinct from the large chondrite groups (H, L, LL, E and carbonaceous), are known to also have chondritic compositions. These meteorites preserve information on conditions at additional formation locations in the early solar nebula. Silicate inclusions from group IAB iron meteorites are one such type. Evidence for their chondritic nature is given and their formation discussed.

We present new observations in the radio continuum of 31 planetary nebulae at 5 and 8 GHz with the Australian Telescope Compact Array. The observations are used to invesigate properties of the interstellar extinction toward Galactic Bulge.

VO-KOREL is a web service exploiting the technology of the Virtual Observatory for providing astronomers with the intuitive graphical front-end and distributed computing back-end running the most recent version of the Fourier disentangling code KOREL.

The system integrates the ideas of the e-shop basket, conserving the privacy of every user by transfer encryption and access authentication, with features of laboratory notebook, allowing the easy housekeeping of both input parameters and final results, as well as it explores a newly emerging technology of cloud computing.

While the web-based front-end allows the user to submit data and parameter files, edit parameters, manage a job list, resubmit or cancel running jobs and mainly watching the text and graphical results of a disentangling process, the main part of the back-end is a simple job queue submission system executing in parallel multiple instances of the FORTRAN code KOREL. This may be easily extended for GRID-based deployment on massively parallel computing clusters.

The short introduction into underlying technologies is given, briefly mentioning advantages as well as bottlenecks of the design used.

The optical position of the short period eclipsing binary XY UMa, which shows large scale star spot activities, coincides within 2 minutes of arc with a radio source, listed in the 4C-, 4CP-, OK-catalogues, and the position obtained with the Effelsberg radio telescope. A fainter star, centered on the radio source position, is according its U-, B-, V-values a K main sequence star. The radio source is non-thermal, and has a spectral index α ~-0.85. If the radio source is identical with the binary, it would imply important consequences about the extragalactic nature of high latitude 4C-sources, the radio background and the high radio luminosity of the binary.

The Extreme Ultraviolet Explorer data archive has been used to study flare energy distributions and infer the role of flares in coronal heating. We have constructed flare number distributions as a function of observed EUV and X-ray emitted thermal energy. We find cumulative flare distributions of the form N(> E) ∝ E−α+1 with α ≍ 1.5–2.6. We present results in the context of spectral type classification.

In this study, we aim to investigate the relation between nuclear activity and the environment for luminous (L[O III] >7.63 × 1041 erg s–1) Active Galactic Nuclei (AGN) - that, at these luminosities are classified as quasi-stellar objects (QSOs) - using a sample of 436 type 2 QSOs. Recent studies suggest that there is an excess of interacting hosts in luminous AGN, indicating that interactions trigger the nuclear activity. In order to examine this, it is necessary to select a control sample of non-active galaxies, matched to the active ones by the properties of the host galaxies, such as distance and stellar mass. We present here the results of the search for such a control sample.

We report on an unprecedented source of Planetary Nebulae (PN) discovered from AAO/UKST Hα survey images of the Southern Galactic Plane. A pristine region of PN discovery space is being sampled due to the excellent depth, coverage, resolution and uniformity of the Hα survey. Large numbers of new PN are being found (~1000 so far). They are typically more evolved, obscurred and of lower surface brightness than in most other surveys. The doubling of known PN should have a significant impact on many aspects of PN research.

A progress report on theoretical work on the formation of a continuum in low-density stellar envelopes. Preliminary results are given on a comparison between the recombination case and the case for a semi-empirical approach including the effect of collisions from the ground state.

Using the IUE satellite we obtained high resolution UV spectrograms (1200 < λ < 3200 Å) of the S Dor type variable R 71 in the LMC. The IUE observations were supplemented by coordinated groundbased high dispersion spectroscopy and by photometric observations. From these observations we derive for the minimum state of R 71 the following stellar parameters: L = 2.0 × 105 L⊙, R ≈ 81 R⊙, Teff ≈ 13 600 K. For the expanding envelope we find a surprisingly low temperature of only about 6000 K and an apparently decelerated velocity field with a maximum outflow velocity of ~ 127 km s−1. The minimum state mass loss rate is in the order of 3 × 10−7 M⊙ y−1. Our results support the suggestion that the visual light variations of the S Dor type variables are produced by strong density variations of the expanding envelopes of these objects. A detailed study is forthcoming in Astronomy & Astrophysics.

Wandering in the wilderness (1) of search space and (2) among the stars.

My summary will certainly leave out much fine work but will stress a few of the points that impressed me.

First, I note remarkable progress since 1967 when I last worried about the interplanetary complex, particularly the new observations from space and of very small particles. I am delighted to see the ground based Zodiacal Light observers, like Weinberg and Dumont, converging on their observations both of polarization and of intensity. The larger particles are clearly the major contributors particularly away from the Sun. This forces the theoreticians and the laboratory people to find out how these larger particles produce the observed polarization including the negative polarization. Theoreticians always can prove the answer when it is known.

We investigate the magnetic sensitivity of molecular lines observed in sunspot umbrae and briefly discuss their major differences compared to atomic lines.

The study of the nongravitational effects on comets began slightly more than a century and a half ago. As is well known, Encke (1819) demonstrated that comet 1819 I had a revolution period of not more than a few years and that the same comet had also been observed in 1786, 1795 and 1805. The observations clearly required that the revolution period be about 3.3 years, and Encke went on to remark that, after approximate allowance had been made for the perturbations by the planets, the average revolution period seemed to be 1207.9 days between 1795 and 1805, but only 1207.3 days between 1805 and 1819. As a result of a more refined computation of the planetary perturbations, the following year he (Encke 1820) was able to confirm these figures and find in addition that the average period between 1786 and 1795 was as much as 1208.1 days.

We have imaged more than thirty early-type galaxies in the K-band to investigate their stellar populations. Our surface brightness fluctuations (SBF) measurements for the nearest 14 galaxies produce a mean fluctuations magnitude in the K-band of The scatter in the Virgo cluster is small at 0.18 mag, which implies that infrared SBF is potentially a good distance indicator (Pahre & Mould 1994). Inspection of the simple stellar population tracks of Worthey (1994) suggests that a plot of the fluctuation color against broadband color (V – I) might be useful in discriminating between age and metallicity effects in elliptical galaxies. We have measured (r – K) color gradients for the entire sample utilizing three methods, two of them independent of sky-subtraction errors, as found in Sparks & Jørgensen (1993). Our color gradients are consistent with a mean metallicity gradient of 0.14 mag dex−1, which is somewhat smaller than that implied by optical color and line gradients alone, suggesting that age gradients may also be important. Finally, we have constructed an infrared Fundamental Plane (FP) which is consistent with its optical counterpart; continued work will determine if there is a significant change in the tilt of the FP between the optical and infrared.