Special Colloquium
Prof. Fred K.Y. Lo	ORATED

NRAO Charlottesville, USA

Powerful water mega-masers can be found in accretion disks in the nuclei of some galaxies. Besides providing a measure of the mass at the nucleus, such mega-masers can be used to determine the angular diameter distance to the host galaxy, based on a simple model. We will explain the importance of determining the Hubble Constant to a high accuracy for constraining the equation of state of Dark Energy and describe the Mega-maser Cosmology Project that has the goal of determining the Hubble Constant to better than 3%. Time permitting, we will also present a status report of the NRAO and some key science projects of the NRAO facilities for addressing key astrophysical problems.

	Main Colloquium
Dr. Yiannis Contopoulos	ORATED

Academy of Athens

Measurements of the pulsar braking index in the case of 400 pulsars yield ”anomalous” values very different from the ”canonical” value 3. This implies that our understanding of the structure of the pulsar magnetosphere is not yet complete. Based on recent global MHD solutions without kinks or discontinuities on the light cylinder, I will present my thoughts on pulsar spindown, magnetospheric variability, dissipation, and pulsar wind acceleration. I will finally discuss the possibility for a neutron star magnetic cycle similar to the solar cycle.

	Special Colloquium
Prof. Andrea Ferrara	ORATED

SISSA, Trieste

TBA

	Main Colloquium
Dr. Jan Tauber	ORATED

ESA Noordwijk

Planck (http://astro.estec.esa.nl/Planck) is an astronomical satellite part of the Scientific Programme of the European Space Agency, due to be launched in the second half of 2008. It is designed to image the anisotropies of the Cosmic Microwave Background (CMB) over the whole sky, with unprecedented sensitivity (DT/T   2x 10-6) and angular resolution ( 5 arcminutes). Planck will provide a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure. The ability to measure to high accuracy the angular power spectrum of the CMB fluctuations will allow the determination of fundamental cosmological parameters such as the density parameter (o) and the Hubble constant Ho, with an uncertainty of order a few percent. In addition to the main cosmological goals of the mission, the Planck sky survey will be used to study in detail the very sources of emission which ``contaminate" the signal due to the CMB, and will result in a wealth of information on the properties of extragalactic sources, and on the dust and gas in our own galaxy. The ability of Planck to measure polarization across a wide frequency range (30-350 GHz), with high precision and accuracy, and over the whole sky, will provide unique insight into specific cosmological questions, but also into the properties of the interstellar medium. I will present an overview of the Planck mission, its scientific objectives, the key elements of its technical design, and its current status.

	Special Colloquium
Prof. Norbert Langer	ORATED

Utrecht University

TBA

	Main Colloquium
Dr. Annie Zavagno	ORATED

OAMP, Marseille

Many physical processes linked to HII regions can trigger star formation. In the first part of my talk, I will review these processes. Infrared observations shows that bright IR sources are observed on the borders of Galactic HII regions. Studies of these sources reveal that many are young stellar objects. This kind of star formation can be studied in the framework of the collect and collpase process (Elmegreen & Lada 1977), expected to form massive stars in a collapsing dense layer surrounding the ionized region. This layer results from the accumulation of neutral material between the ionization front and the shock front during the supersonic expansion of the ionized region. I will show some examples of Galactic HII regions for which this process is clearly at work. I will then present the perpective for such a study using current (Spitzer, ATLASGAL) and forthcoming facilities (Herschel).

	Main Colloquium
Dr. Dimitrios Gouliermis	ORATED

MPIA Heidelberg

The Magellanic Clouds (MCs) offer an outstanding variety of HII regions related to star forming stellar systems. Among these systems, stellar associations host large samples of low-mass stars (with M < 1 Msolar), currently in the act of formation. These pre-main sequence (PMS) stars provide a unique snapshot of the star formation process, as it is being recorded for the last 20 Myr, and they give important information on the low-mass Initial Mass Function (IMF) of their host environments. I will present the latest results from observations with the Hubble and Spitzer Space Telescopes of star-forming regions in the MCs, and discuss their importance for a comprehensive analysis of the most recent star formation and the IMF in the low-metallicity environments of these galaxies.

	Special Colloquium
Prof. Jacques Roland	ORATED

Institut d'Astrophysique, Paris, France

The source 1803+784 shows radio variability on time scales of a day. The characteristics of IDV sources can be explained, if the relativistic ejection of the plasma responsible for the radio emission is perturbed by, for instance, a warp in the central part of the accretion disk. Due to a chaotic behavior of the solution, a period perturbation can produce an apparently non-periodic and chaotic variation of the flux and a chaotic dependence of the frequency.

	Special Colloquium
Dr. Rainer Rolffs	ORATED

MPIfR

Hot Molecular Cores are an early stage of massive star formation. They are compact condensations of molecular gas, which is heated by embedded protostars. The evaporation of ice mantles from dust grains and the high temperatures lead to strong line emission from a variety of molecules. This thesis is a step towards revealing the structure of hot cores, i.e. their distribution of density, temperature and velocity. This aim can only be achieved by comparing models of the source structure to observations. The emission from a model source is calculated by the Monte Carlo radiative transfer program Ratran and processed in the same way as the emission from the real source. The observational data (from APEX and Effelsberg) are spectral lines from HCN in different excitations, including the vibrational state. A result is that spherically symmetric models need an infall velocity field, a density power law index of around -2 and an HCN abundance that rises with temperature. The dust radiative transfer code DUSTY was used to derive the temperature structure, suggesting a steeper gradient in the inner part, which fits the data. Additionally, SMA maps in the HCN(4-3) transitions toward two of the sources, G10.47 and W51e, were obtained. High angular resolution reveals that the structure is not well represented by spherical models, but consists of multiple sources, which themselves are probably not spherical. The SMA data illustrate the great potential in constraining more complicated, 2- or 3-dimensional models, which will be ultimately tested by ALMA.

	Main Colloquium
Dr. Frank Eisenhauer	ORATED

MPE Garching

High angular resolution adaptive optics imaging and spectroscopy have shown beyond any reasonable doubt that the Galactic Center harbors a supermassive black hole. We have been able to determine the three dimensional orbits of stars within the central light days, and the flaring activity from the black hole gives first insights to the physical processes close to the last stable orbit. The Galactic Center constitutes the ideal laboratory for studying physics in the vicinity of such objects. Here we give an update on the latest results, and outline the next steps towards even higher angular resolution with infrared interferometry and extremely large telescopes. These experiments — and most notably the planned GRAVITY experiment for the VLTI — give promise to directly probe the physics and space-time curvature just outside the event horizon.

	Special Colloquium
Vitaly Chetik	ORATED

MPIfR

Es wird ein neues Backend für den neuen 7-beam 32-GHz-Empfänger für das 100-m-Radioteleskop in Effelsberg vorgestellt. Die Notwendigkeit des neuen Backends entstand durch den Aufbau des neuen Empfängers als geschaltetem Pseudo-Korrelations-Empfänger. Hierzu werden in allen Frontend-Kanälen elektronische 180 Grad-Phasenschalter eingesetzt, die durch zyklisches Schalten jeweils die beiden Kanäle eines korrelierten Signalzuges gegeneinander vertauschen. Die Total-Power- Erfassung am Detektor erfolgt, statt mit den üblichen V/F-Convertern, mit 18 Bit AD-Wandlern bei einer maximalen Abtastrate von 666 kSample/s. Insgesamt stehen 32 differentielle analoge Eingänge zur Verfügung und decken den gesamten Bedarf eines Empfängers ab. Das neue Backend wird in unmittelbarer Nähe des Empfängers montiert und überträgt die bereits vorverarbeiteten Daten zum Backend-Raum über eine optische Übertragungsstrecke.

	Main Colloquium
Prof. Paola Caselli	ORATED

School of Physics and Astronomy, University of Leeds, UK

High degrees of the deuterium fractionation are observed in pre-stellar cores and during the earliest stages of the star formation process. Here I will review how observations of deuterated species have improved our knowledge of the physical and chemical processes in a wide range of star forming regions and how they can help in constraining important parameters such as the electron fraction and the kinematics. Results from a survey of ortho-H2D+ toward low-mass starless cores will be presented. Finally, I shall show that the coupling of observations with simple chemistry and radiative transfer codes suggests that the dust in pre-stellar core nuclei (the future stellar cradles) has a higher opacity, consistent with fluffy dust, and that the cosmic ray-ionization rate cannot be significantly larger than 1x10^{-17} s^{-1}.

	Special Colloquium
Prof. Gordon Stacey	ORATED

Cornell University, Ithaca, NY, USA

We present the highlights of our first observing runs with the redshift (z) and Early Universe Spectrometer (ZEUS). Using the CSO on December of 2006, and March of 2007, we detected 13CO(6-5) line emission from the starburst nucleus of NGC 253, CO(6-5) and/or CO(7-6) and/or [CI] 370 um line emission from 6 ULIRG galaxies, and redshifted [CII] line emission from a hyperluminous galaxy at z = 1.12. We will discuss the implications of our new data sets and our plans for the future.

	Special Colloquium
Dr. Matt Bradford	ORATED

JPL Astrophysics / Caltech Submillimeter Astronomy

We present first results with a new broadband mm-wave grating spectrometer Z-Spec. Z-Spec covers the full 1-mm atmospheric window at a resolving power of 250–300 instantaneously, providing a full line + continuum over this band. The instrument is now working well at the CSO, and we present some new spectra of nearby galaxies and ULIRGS. In addition to 12CO J=2-1 and the isotopes, Z-Spec measures the J=3-2 transitions of HCN, HCO+, and HNC. We discuss these preliminary results, and our plans further surveys, both in the local-universe and in the high-redshift submillimeter galaxies.

	Main Colloquium
Dr. Andrej Sobolev	ORATED

Astronomical Observatory, Ural State University, Ekaterinburg, Russia

S235 is the brightest HII region in a complex within a huge Giant Molecular Cloud. The complex contains several HII regions born by O-type stars and shows signs of the ongoing star formation. This is confirmed by the presence of methanol and water masers. Several embedded stellar clusters, revealed by the IR star counts and also seen in Spitzer data, are distributed around S235. This prompts that formation of the clusters is triggered by expansion of S235 HII region surrounding O9.5V star. 13CO(1-0) and CS(2-1) mapping reveals clumps at the different stages of star formation phenomena, from its onset to dispersion of the envelope around the cluster. Some other clusters, S235A and S233IR in particular, are situated rather far from expanding HII regions and mainly consist of low mass stars. Optical spectroscopy of the objects in the region S235A-B have shown that the main optical objects in the region are created by the low and intermediate type stars. Several T Tauri stars (S235B is the brightest) are found. So, the study of the S235 star forming complex shows that the powerful massive stars can trigger star formation while in some places the stars with the high, intermediate and low masses can appear almost simultaneously.

	Special Colloquium
Sang-Sung Lee	ORATED

MPIfR Bonn

We present results from a large global VLBI survey of compact radio sources at 86 GHz. The main goal of the survey is to increase the total number of objects accessible for future 3-mm VLBI imaging by factors of 3-5. The observations have yielded images for 109 sources, extending the database of the sources imaged at 86 GHz with VLBI observation by a factor of 5, and only 6 sources have not been detected. 12 objects have been detected but could not be imaged due to insufficient closure phase information. Radio galaxies are less compact than quasars and BL Lacs in sub-milliarcsecond scale. Flux densities and sizes of core and jet components of all imaged sources have been estimated using Gaussian model fitting. The cores of 70% of the imaged sources are resolved. The core brightness temperatures of the sources peak at sim 10^{11}K and only 1% have brightness temperatures higher than 10^{12}K. Cores of Intraday Variable (IDV) sources are smaller in angular size than non-IDV sources, and so yield higher brightness temperatures. Using the relation of the intrinsic and observed properties of relativistic jets, the intrinsic brightness temperature of T_{ m 0} = 6.5_{-0.8}^{+1.1} imes 109K is deduced for 85 sources selected from our 3mm-survey data. This value is less than the one found from the database at 15 GHz in the case of the median-low state by a factor of  5. Despite the difference in both samples, the decrease of the intrinsic brightness temperature may imply that the ultra compact cores in AGNs at 86 GHz are magnetic field dominated. Under the equipartition condition between the magnetic field energy and particle energy density, the absolute distance of the VLBI core can be predicted. From the database of VLBI survey at lower frequencies (2, 8, 15GHz) and our measurement, the brightness temperatures in source frame are investigated in the sub-parsec scale of the compact radio sources. From the very vicinity of the central engine, the brightness temperatures increase slowly and then rise with steeper slope. This implies that the jets are collimated and accelerated by the magnetically driven force, as predicted by the relativistic jet models for the magnetic acceleration.

	Main Colloquium
Dr. Ulrich Bastian	ORATED

ARI, University of Heidelberg

The space astrometry mission ”Gaia”, under development by ESA and to be launched in late 2011, will revolutionize our view of the Galaxy and strongly influence many other fields of astronomy. Gaia will measure positions, proper motions and parallaxes for one billion stars to about 20th magnitude at micro-arcsecond precision, as well as multi-colour photometry. In addition radial velocities, surface temperatures, metallicities etc will be derived for a very significant subset. I will describe the mission and briefly touch the science of Gaia and the heritage from its predecessor Hipparcos.

	Special Colloquium
Adam Sodor	ORATED

Konkoly Observatory, Budapest, Hungary

I report on our ongoing project, a systematic survey of fundamental mode Galactic field RR Lyrae variable stars with the 60-cm automated telescope of the Konkoly Observatory at Budapest, Hungary. Our accurate and uniquely extended multicolour measurements are focused on the periodic light curve variations of these variables, the so-called Blazhko modulation. We observed 14 fundamental mode RR Lyrae stars so far and much more than expected, 8 of them, have been found to show the Blazhko effect. Modulation seems to occur much more frequently among these stars than it was estimated in any previous survey, most probably due to the discovery of small-amplitude modulations. The larger occurrence rate of the light curve modulation of RRab stars makes it even more important to find the still lacking explanation of the hundred years long known Blazhko phenomenon. Besides reviewing our scientific results, I also present some details of the time-series analysis methods and tools we use during our studies of pulsating variable stars.

	Special Colloquium
Dr. Juan Uson	ORATED

National Radio Astronomy Observatory, Charlottesville VA, USA

Superthin galaxies are bulgeless, late-type spiral galaxies seen edge-on. HI synthesis observations probe the kinematic structure of their interstellar medium. I shall present the results of high-sensitivity VLA observations of UGC7321, IC2233, UGC3697 and UGC10043. Two of these galaxies are rather isolated while the other two are the dominant members of small groups. We have detected a pattern of “corrugations” in IC2233, the first such detection in neutral Hydrogen in an external galaxy. UGC 10043, not quite a superthin galaxy, has presented us with an unexpected, rich interaction with a previously unknown companion which is reminiscent of the M51 system (the Whirlpool galaxy) “seen from the side.” These results have required the development (in collaboration with Bill Cotton) of an algorithm to correct the VLA beam-squint. This in turn has presented us with the pieces of a VLA pipeline. I’ll discuss briefly this development and (time-permitting) will include a “live” demonstration of the squint-correcting algorithm. This takes   11 minutes and could be done after the talk for those that might be interested. The algorithm runs in the “Obit” package (a python and C port of AIPS done by Cotton which is available for downloading from (http://www.cv.nrao.edu/, ilde,,bcotton/Obit.html). A number of test memos describing new procedures are also available from this web page (EVLA memo numbers 113 through 118; more are forthcoming).

	Main Colloquium
Dr. Luka Popovic	ORATED

Astronomical Observatory, Belgrade, Serbia

This talk will be about the emission line regions (Broad Line Region - BLR and Narrow Line Region - NLR) in Active Galactic Nuclei (AGN) and their possible connection with the radio emission. We will discuss the BLR (including Fe K-alpha line) and NLR geometry and its possible connection with radio emission geometry of AGN. Moreover, we are going to present some recent investigation of Mrk 533, where we found line emissions from the active type 2 Seyfert nucleus in the center and also from the H II regions in a spiral structure and a circumnuclear region. The gas kinematics shows regular non-circular motions in the wide range of galactocentric distances from 500 pc up to 15 kpc. The maps of inward and outward radial motions of the ionized gas were constructed. We found that the NLR is composed of at least two (probably three) kinematically separated regions. We detect a stratification in the NLR of Mrk 533 with the outflow velocity ranging from 20-50 km/s to 600-700 km/s, respectively, on the radial distances of sim2.5 and sim1.5 kpc. The maximal outflow velocity comes from the nucleus and corresponds to the position of the observed radio structure, which is assumed to be created in an approaching jet. We suggest that these ionized gas outflows in this galaxy are triggered by the radio jet intrusion in an ambient medium.

	Special Colloquium
Steffen Zimmermann	ORATED

FH Darmstadt

In dieser Arbeit wurde eine neue Kallibrationseinheit für VLBI aufgebaut und untersucht, welche langfristig die vorhandene Schaltung ersetzen soll. Dazu wurden Konzepte untersucht, eines davon ausgewählt und aufgebaut. Die bei VLBI Messungen aufgezeichneten Daten müssen neben der Frequenz- und Zeitinformation auch Informationen über die Phasenlage zum Zeitpunkt der Messung enthalten. Dies wird dadurch erreicht, dass Signale in den Eingang der radioastronomischen Empfangssysteme eingespeist werden, welche diese Informationen beinhalten. Damit steht ein bekanntes Kalibrationssignal in den aufgezeichneten Messdaten zur Verfügung. Dieses Kalibrationssignal wird durch eine Pulsfolge erzeugt, welche an ein hochgenaues Zeitnormal angebunden ist. Es wird in den Eingang der radioastronomischen Empfangssysteme eingespeist, um den gesamten Empfangspfad mit abzubilden. Die Basis dieser Pulse ist ein aus dem Wasserstoffmaser abgeleitetes 5 MHz Signal, die Steilheit der Pulse muss so hoch sein, dass auch im Bereich bis 50 GHz noch Spektralanteile gemessen werden können. Dazu werden spezielle Bauelemente verwendet, die auf hohe Pulssteilheit gezüchtet wurden.

	Special Colloquium
Christian Peter Manko	ORATED

FH Rhein-Sieg

Im Radioteleskop Effelsberg werden für die Übertragung von ZF-Signalen bis 500 MHz Bandbreite Koaxialkabel verwendet. Dieses Übertragungsmedium ist damit an seiner Grenze angelangt. In modernen radioastronomischen Empfangsystemen soll das zu übertragende Analogsignal daher direkt im Empfänger digitalisiert und mittels Glasfaserkabel zur Weiterverarbeitung in den Backend-Raum übertragen werden. Um Bandbreiten von 500 MHz und mehr erfassen zu können werden analog/digital Wandler mit Taktraten > 1 GHz eingesetzt. Je nach Auflösung dieser Wandler können schnell Datenraten von einigen Gigabit pro Sekunde erreicht werden. Dieser hohe Datenstrom soll möglichst unverändert am Backend zur Verfügung stehen. Daraus ergeben sich einige essenzielle Schwierigkeiten. In dieser Arbeit wurde eine 10GbE Strecke aufgebaut und auf maximale Übertragungsrate optimiert. Der Aufbau der Hardware, die Testmethoden und Ergebnisse werden in dieser Arbeit dokumentiert und vorgestellt. Die Glasfaserstrecke wurde im Institut in Bonn aufgebaut und hier unter Laborbedingungen getestet werden.

	Special Colloquium
Nikhil Jethava	ORATED

MPIfR Bonn

A development of superconducting bolometers was started in collaboration between the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn and the Institute for Photonic Technologies (IPHT) in Jena, Germany. The voltage biased superconducting bolometer (VSB) offers various advantages over the traditional semiconducting bolometer; it is faster, more sensitive, has a higher dynamic range, offers complete micro-lithographic fabrication and can be multiplexed with Superconducting Quantum Interference Devices (SQUIDs). The superconducting thermistor, deposited on a low stress silicon nitride membrane, is a bilayer of gold-palladium and molybdenum and is designed for a transition temperature of 450 mK. The bolometers were designed for the 1 mm atmospheric window. The bolometers are divided into three different categories, High-G, Medium-G and Low-G, depending on their thermal conductance. The thermal conductance of Medium-G layout is appropriate for operation in a 300 K background, and for experimental purposes, the silicon nitride membranes of Medium-G layout were structured into 8-legs and 16-legs spider-like geometries. The incident radiation is absorbed either by a continuous titanium film or by capacitive crossed dipole absorbers made of gold-palladium. A bolometer model has been developed to understand the physics of the bolometers. Using the COSMOS finite element analysis (FEA) tool, the thermal conductance is obtained for the thermistors of different geometries. The ideal performance of the bolometer is derived from the VSB theory, and the results from the bolometer model are compared with experiments. FEA simulations showed that the deposition of a gold ring around the absorbing area would slightly increase the sensitivity of the bolometer. Therefore, a 16-legs Medium-G layout was fabricated, with a gold ring around the absorbing center patch of the silicon nitride membrane. For the Medium-G layout bolometer with gold ring, the measured optical noise equivalent power (NEP) is 1.7 ×10−16W/Hz and the time constant is in the range between 1.4 and 2 ms. The gold ring increases the heat capacity and this is a way to increase the time constant of the bolometer.

	Main Colloquium
Dr. Andrzej Marecki	ORATED

Torun Centre for Astronomy, N. Copernicus University, Torun

The activity of a galaxy is an episodic phenomenon: virtually every galaxy can become active under certain circumstances and, on the other hand, it appears that every active galaxy will eventually become a normal, i.e. inactive galaxy. Radio observations are ideally suited to study the history of galaxies as the appearance of extragalactic radio sources can be regarded not only as a signature of present but also as a record of past activity (or both) of their host galaxies. How long the active phase can be? Do we observe “post-active” galaxies? Can the activity be recurrent and if so, what are the observable signatures of restarted activity? I will try to answer these questions.

	Special Colloquium
Dr. Wolfgang Troeger	ORATED

Max-Planck-Innovation, Muenchen

TBA

	Main Colloquium
Dr. Bojan Nikolic	ORATED

Cavendish Laboratory, University of Cambridge, UK

I will present a technique for the accurate estimation of large-scale errors in an antenna surface using astronomical sources and detectors. The technique requires several out-of-focus images of a compact source and the signal-to-noise ratio needs to be good but not unreasonably high. The main advantages of this technique compared to alternatives are that it allows measurement over the full range of elevations; requires no extra equipment beyond that used for routine astronomical observing and can requires relatively little time. I will present: simulations illustrating the expected accuracy of the technique; the verification of the technique on the 100-m diameter Green Bank Telescope; and, the application of the measurements to improve the performance of the telescope.

	Main Colloquium
Dr. Konrad Tristram	ORATED

MPIA Heidelberg

Mid infrared interferometry with the MIDI instrument at the VLTI allows us for the first time to resolve the nuclear mid-infrared emission in nearby active galactic nuclei (AGN). We can thus probe the dusty torus, which surrounds the central engine of AGN and which is held responsible for the apparent difference between Seyfert 1 and Seyfert 2 galaxies. I will first present some basics on mid-infrared interferometry and describe how MIDI and the VLTI work. Then I will focus on the detailed study of the Circinus galaxy, the nearest Seyfert 2 galaxy. I will show that our observations reveal a well resolved dust structure, which is oriented perpendicular to the ionisation cone and outflow in this galaxy. Circinus is hence the second direct confirmation of the ”doughnut paradigm”, after NGC 1068. I will also report on the results on the radio galaxy Centaurus A, where most of the emission is unresolved by our interferometric measurements. This unresolved emission is interpreted as synchrotron radiation from the foot of the jet. Taking into account that further targets have been observed successfully, these findings show what an exciting observational tool MIR interferometry is for AGN research.

	Informal Colloquium
Kirill Sokolovsky	ORATED

Lomonosov Moscow University and Astro Space Centre Lebedev, Russia

TBA

	Special Colloquium
Dr. Hong Guang Wang	ORATED

Center for Astrophysics, Guangzhou University, China

Since the discovery of the first pulsar in 1967, nearly 2000 pulsars have been detected, mostly at radio frequencies wave, with a small fraction at high energies. The pulsar community has reached a common agreement that pulsed radio/high energy emission is generated by relativistic particles in some region of the pulsar magnetosphere within the light cylinder, shining like a light house as pulsars rotate. However, the exact radio/high energy emission region is still a matter of debate, accompanied by long-term controversies over pulsar empirical and theoretical models on, e.g. the structures of emission beam (cone-core and patch models), the origins of high energy emission (polar gap and outer gap models), and the origins of multi radio-frequency emission (radius-frequency-mapping (RFM) and non-RFM models). I will review the various efforts on constraining the emission regions, and present the progress in constraining the 3d structure of radio/high-energy emission regions with a new method, and how the work in this respect will improve our understanding on pulsar emission.

	Informal Colloquium
Dr. Xiaohui Sun	ORATED

MPIfR Bonn

We constrain simulated all-sky maps in total intensity and linear polarization, and rotation measure (RM) by observations. For the simulated maps as a function of frequency we integrate in 15 arcmin wide cones the emission along the line of sight calculated from Galactic 3D-models. We test a number of large scale magnetic field configurations and take the properties of the warm interstellar medium into account. From a comparison of simulated and observed maps we are able to constrain the regular large scale Galactic magnetic field in the disk and the halo of the Galaxy. The local regular field is 2 microG and the average random field is 3 microG. The known local excess of synchrotron emission originating either from enhanced CR electrons or random magnetic fields is able to account for the observed high-latitude synchrotron emission. The thermal electron model (NE2001) in conjunction with a proper filling factor accounts for the observed optically thin thermal emission and low frequency absorption by optically thick emission. A coupling factor between thermal electrons and the random mangetic field component is proposed, which increases small scale RM fluctuations and thus accounts for the observed depolarization at 1.4 GHz.

	Main Colloquium
Dr. Ben Metcalf	ORATED

MPA Garching

Low-frequency radio observations of neutral hydrogen during and before the epoch of cosmic reionisation will provide  1000 quasi-independent source planes, each of precisely known redshift, if a resolution of sim 1 arcminutes or better can be attained. These planes can be used to reconstruct the projected mass distribution of foreground material. In principle, mass maps with a formal signal-to-noise per pixel exceeding 10 could be made, even for pixels as small as an arc-second. Both resolution and signal-to-noise can exceed those of even the most optimistic idealized mass maps from galaxy lensing by more than an order of magnitude. Individual dark matter halos could be imaged with high signal-to-noise out to z sim 10. A wide-area survey of 21 cm lensing would also provide very sensitive constraints on cosmological parameters, in particular on dark energy. These are up to 20 times tighter than the constraints obtainable from comparably sized, very deep surveys of galaxy lensing, although the best constraints come from combining data of the two types. The prospects for doing these things with the next generation of low frequency telescopes will be discussed.

	Special Colloquium
Prof. Apostolos Mastichiadis	ORATED

University of Athens

TBA

	Special Colloquium
Dr. Delampady Narasimha	ORATED

Tata Institute of Fundamental Research, Mumbai, India

In 1924 Chowlson gave the formula for Einstein Ring. In 1985, Saslaw, Narasimha and Chitre predicted that a new type of phenomena called Gravity Ring will be observable with VLBI when extended sources with brightness contrast are lensed. I shall explain the formation of Einstein Ring, morphology of the ring and its diagnostic value. I shall demonstrate a few cases of rings and explain how rotation curve of a lens galaxy can be inferred from the neutral hydrogen and OH radio absorption spectrum of the lens.

	Main Colloquium
Dr. Melvin Hoare	ORATED

University of Leeds, UK

Surveys of the Galactic plane to systematically find young high mass stars at various stages of evolution will be discussed. The Red MSX Source (RMS) survey will be described which started with mid-IR bright point sources and followed them up with ground-based near-IR, mid-IR, millimetre and radio observations to identify and characterise massive young stellar objects. Initial identification is complete and the general properties of the sample will be presented. A new high resolution VLA radio continuum survey (The CORNISH Survey) will also be described which aims to deliver an unbiased sample of ultra-compact H II regions. Related multi-wavelength surveys of the plane will be mentioned with relevance to massive star formation.

	Main Colloquium
Dr. Andy Strong	ORATED

MPE Garching

The Galactic magnetic field is closely linked to cosmic-ray and gamma-ray astrophysics. Combining direct measurements of cosmic-ray electrons, indirect measurements via inverse Compton gamma-ray emission from these same electrons, and synchrotron data from radio surveys, it is possible to put good constraints on the magnitude of the field and also gain some information about its variation in the Galaxy. This provides an independent approach, free of some of the assumptions of other methods. The GALPROP project is designed to model in detail the observational consequences of cosmic-ray electron and nucleus production and propagation in the Galaxy. It has been adopted as the standard for the GLAST Gamma-Ray Observatory to be launched early next year. I will describe the current state of this modelling effort and present new comparisons with radio surveys and constraints on the field.

	Special Colloquium
Dipl.-Phys. Stefan Kraus	ORATED

MPIfR-IMPRS

Located in the Orion Trapezium Cluster, Theta 1 Ori C is one of the youngest and nearest high-mass stars (O5-O7) known. Besides its unique properties as an oblique magnetic rotator, the star happens to be a close binary system, which makes it an ideal laboratory to determine the fundamental parameters of young hot stars. In this talk, I will review the results from our long-term interferometric monitoring campaign, in which we traced the orbital motion of the system over the last 12 years, covering nearly a full orbital period. For our observations, we employed bispectrum speckle interferometry at visual wavelengths as well as VLTI/AMBER near-infrared interferometry which also allowed us to reconstruct a first VLTI aperture-synthesis image, showing the system with an angular resolution of about 2 milli-arcseconds. From the astrometric data, we derive constraints on the masses of the two young high-mass stars and on the distance to the center of the Orion Nebula. Finally, I will discuss our future plans to improve the derived mass and distance estimates and to spatially resolve the wind-confinement region around the primary star, in which magnetically channeled winds from the two stellar hemispheres are expected to collide and to form an equatorial cooling disk.

	Special Colloquium
Dr. Cristiano da Rocha	ORATED

Goettingen

TBA

	Main Colloquium
Matthias Kadler	ORATED

RAIUB & MPIfR

GLAST, the Gamma-Ray Large Area Space Telescope, will provide unique new insights into the physics of AGN jets. Scheduled for launch in December 2007, GLAST’s main instrument LAT will survey the gamma-ray sky in the 20 MeV to 300GeV energy range and will provide a factor of  30 or more advance in sensitivity compared to the very successful EGRET detector onboard CGRO in the 90’s. The by far largest class of identified EGRET sources is represented by blazars, the very same objects whose parsec-scale jets can be resolved by VLBI techniques and thus, naturally, many of the main scientific questions addressed by GLAST and VLBI are the same: how are relativistic jets formed; how are they collimated and accelerated; how can their broadband spectral emission be explained? In this talk, I will give an outline of the GLAST/LAT AGN Science group activities in preparation for the first year of GLAST/LAT science operations with a special emphasis on synergistic efforts with radio and VLBI AGN science.

	Main Colloquium
Prof. Matt Griffin	ORATED

Cardiff University

SPIRE, the Spectral and Photometric Imaging Receiver, is one of the three instruments to fly on ESA’s Herschel Space Observatory. It contains a three-band imaging photometer operating at 250, 350 and 500 microns, and an imaging Fourier transform spectrometer covering 200-670 microns. SPIRE will be used for many galactic and extragalactic science programmes. I will describe the instrument and its observing modes, and use examples from the SPIRE Consortium’s Guaranteed Time programme to illustrate its scientific capabilities.

	Special Colloquium
Dr. Yasuhiro Murata	ORATED

ISAS/JAXA and NAOJ, Japan

Following the success of the VSOP(VLBI Space Observatory Programme), the world’s first Space-VLBI mission dedicated for astronomy, the next generation Space-VLBI mission VSOP-2 has been recently approved to move to the development phase (Phase-B) by JAXA. Currently ASTRO-G (VSOP-2) project will be formally started from this June and the ASTRO-G satellite will be launched in 2012. ASTRO-G employs a 9.6-m off-axis paraboloid antenna with cryogenically cooled receivers operating at 22 and 43 GHz and an uncooled 8 GHz receiver. Each band has dual-polarization. The apogee height of 25,000 km will yield an angular resolution of 38 micro-arcseconds at 43 GHz. Phase-referencing capability with fast switching and precise orbit determination are being considered for increasing the number of objects and possible astrometric observations. With direct imaging capability at unprecedented angular resolution enabled by these unique technical capabilities of ASTRO-G, we aim to approach some of the fundamental problems in modern astronomy and astrophysics. In this presentation, the current status of technical development of ASTRO-G and science goals of the mission will be presented.

	Main Colloquium
Dr. Russ Taylor	ORATED

University of Calgary

Advances in techniques for wide-field interferometric imaging and in array receiver technology on large single-dish telescopes have opened up the possibility of imaging radio emission over large areas of sky at high angular resolution. Polarized radio emission in particular is a unique tool for investigations of cosmic magnetic fields. This talk will describe surveys of the polarized radio emission from the plane of the Milky Way Galaxy and the deep extragalactic sky using the aperture synthesis imaging array at the Dominion Radio Astronomical Observatory in Canada and the Arecibo Radio Telescope in Puerto Rico. These projects yield insights into the properties of the magneto-ionic medium of the Galaxy and the polarization of faint emission from distant galaxies, and help pathfind the scientific journey to the SKA key science goal to understand the origin and evolution of the magnetic Universe.

	Main Colloquium
Dr. John Kirk	ORATED

MPI fuer Kernphysik, Heidelberg

The theoretical problems posed by sources of synchrotron radiation that appear to have very high brightness temperatures have been puzzling radio astronomers for nearly forty years. The most extreme examples are intra-day variable radio sources. In several cases the cause of the variability is now known to be extrinsic. Nevertheless, observations imply a brightness temperature in excess of 100TK, well above the conventional inverse Compton limit of 1TK. Many explanations have been advanced to explain this apparent contradiction, ranging from proton synchrotron radiation to coherent emission mechanisms. I will briefly summarize these, before presenting a recently developed model based on conventional synchrotron theory applied to an electron distribution function suggested by the dynamics of relativistic shocks.

	Informal Colloquium
Dr. Jeroen M. Stil	ORATED

University of Calgary, Canada

We discovered several large structures in the magneto-ionic interstellar medium, that depolarise background extragalactic radio sources in the NRAO VLA Sky Survey (NVSS). Polarised radio emission of extragalactic sources can be depolarised by differential Faraday rotation across the solid angle of the source, or across the frequency band of the observations. We find no correlation between the amount of depolarisation and H-alpha intensity, which suggests that our objects reveal structure in the Galactic magnetic field. Correlation with published rotation measures shows that at least some of our objects depolarise background sources by differential Faraday rotation over the frequency range of the NVSS. This implies structure in foreground rotation measure with amplitude up to 200 rad/m2 on angular scales of approx. 10 degrees, up to 20 degrees from the Galactic plane. The largest feature is a magnetized bubble with angular diameter 32 x 17 degrees (220 pc x 120 pc) associated with the Gum nebula.

	Main Colloquium
Prof. Joseph Mohr	ORATED

University of Illinois

Galaxy cluster surveys are enormously powerful tools for determining the nature of dark energy and delivering a precise measurement of the expansion history of the universe. Promising new mm-wave survey instruments are coming online that have the sensitivity to carry out a census of galaxy clusters from the present back to the young universe. These new cluster catalogs will enable studies focused on galaxy evolution and black hole accretion over cosmic time. These catalogs contain a wealth of information about the large scale evolution of the universe over the same timescales; however, there are significant challenges in extracting this cosmological information from galaxy cluster surveys. These challenges include developing a precise understanding of the survey selection and estimating cluster masses over the full redshift range of the surveys. Recent developments in this field suggest a way forward to meet these challenges.

	Special Colloquium
Prof. Edwin E. Salpeter	ORATED

Cornell University, USA

TBA

	Main Colloquium
Prof. Heinz Andernach	ORATED

University of Guanajuato

From Abell et al’s 1989 catalogue of 5250 clusters we selected about 2600 of those with a morphological type (BM or RS) indicating the presence of one or a few dominant galaxies. Digitized Sky Survey images were used to identify the brightest cluster members (BCMs). In order to assess their cluster membership, complementary data were extracted from public databases (NED/LEDA) and data for their host clusters were taken from the Abell cluster redshift compilation (”ZACO”) maintained by the author. For a subsample of BCMs in 1137 clusters with very ”early” BM types (I and I-II) we classify their morphology and confirm the predominance of early-type galaxies, and almost half of them are potential cD galaxies. For over 300 of these clusters more than 10 galaxies with redshift were available in ZACO, and we derived the ”peculiar velocity” of the BCM relative to the cluster mean velocity, both in km/s and in units of the cluster velocity dispersion. This sample, about 13 times bigger than any one previously analysed, confirms previous results in that half of all BCMs have a peculiar velocity of  0.35 the cluster velocity dispersion. While the effect is independent of the number of galaxies used to determine the cluster redshift and velocity dispersion, the BCM peculiar velocity decreases weakly with cluster richness, and with BM type, but depends more strongly on the morphological type, with cD galaxies having lower peculiar velocities than ellipticals in general. Thus BCMs are not at rest in the potential well of their clusters, which is not only difficult to explain in the framework of bulk cluster evolution, and indicate that the dynamical and morphological evolution of the BCMs depend on local conditions rather than on global properties of the clusters.

	Main Colloquium
Tim Huege	ORATED

MPIfR Bonn

In the last few years, radio detection of cosmic ray air showers has experienced a true renaissance, becoming manifest in a flurry of new activities. One of the novel experiments is the LOPES project, the efforts of which are being accompanied by new studies of the underlying emission mechanism, in particular in the framework of “geosynchrotron radiation”. In this talk I will describe the concept, current status and recent results of the LOPES experiment and compare its findings with the predictions made by the geosynchrotron model for radio emission from extensive air showers, followed by a short outlook on the future of radio detection of cosmic rays in the Pierre Auger Observatory.

	Special Colloquium
Prof. Craig Sarazin	ORATED

University of Virginia, Charlottesville, USA

Clusters of galaxies are the largest relaxed systems in the Universe, and contain hundreds of galaxies a regions which are several Mpc across. The dominant form of baryonic matter is clusters is hot intracluster gas, which has more mass than the stars and galaxies by a factor of about 5. Two aspects of the interactions of radio and the X-ray gas will be discussed. First, I will describe calculations of the effect which cluster mergers have on the Sunyaev-Zeldovich (SZ) effect from clusters. The SZ effect is the scattering of photons from the Cosmic Microwave Background by hot electrons in the cluster. Although the details (images, the central peak, etc.) of the SZ effect are dramatically affected by mergers, the integrated SZ effect over the entire cluster is remarkably insensitive to mergers. I show that this occurs because the integrated SZ effect depends only on the total electron thermal energy content of the cluster. Second, I will discuss recent observations of the interaction of central radio sources with the X-ray gas in clusters. Previous Chandra observations had shown evidence for “radio bubbles” in the centers of clusters. Radio bubbles are regions of reduced X-ray emission coincident with radio lobes, and are often surrounded by bright shells of X-ray emission. “Ghost bubbles” have also been seen in some cases; these are holes in the X-ray emission, but without high frequency radio emission. Our recent low frequency radio observations show that the ghost bubbles generally contain very steep spectrum radio emission. Also, deeper Chandra images often show “tunnels” of reduced X-ray emission with coincident faint, low frequency radio emission connecting the bubbles. These observations provide interesting constraints on the history of radio activity in giant ellipticals, the total energetics of radio jets, and the energy input into the X-ray gas.

	Special Colloquium
Jian-Rong Gao	ORATED

SRON Groningen & Kavli Institute for Nanoscience, Delft

Superconducting phonon-cooled hot electron bolometer (HEB) mixers are the devices of choice for low noise heterodyne detectors operating at frequencies beyond 1.4 THz. Since the pioneering work of superconducting HEB mixers by the Russia group at Moscow, the performance of such detectors has improved dramatically, such as receiver noise temperature, IF gain bandwidth, operating frequency, and LO power requirement. NbN HEB mixers have been operated at ground telescopes, demonstrating true heterodyne detection and they are used for two high-frequency bands in The Heterodyne Instrument for the Far Infrared (HIFI) on board of the Herschel Space Telescope. In my talk I will highlight progress in HEB receivers mainly achieved through close collaboration between SRON and TU Delft. This includes the best receiver noise temperatures obtained in spiral and twin slot antenna coupled HEB mixers at 1.6 and 2.5 THz by introducing new contact-process and -structure; and demonstration of a 2.8 THz heterodyne receiver using a HEB as a mixer and a THz quantum cascade laser (QCL) as a local oscillator. This combination has led the best DSB receiver noise temperature of 1050 K at 2.8 THz, which corresponds to 7.7h/k (so-called the quantum noise). I will also briefly report our studies of THz QCLs, aiming for the application as local oscillator, which include the unexpected beam patterns of metal-metal waveguide QCLs with sub-wavelength cavity dimensions, the beam patterns of surface plasmon QCLs, and the phase-locking of a two-mode THz QCL.

	Informal Colloquium
Prof. Peter Maass	ORATED

Universität Bremen

Denoising and deconvolution problems are amongst the most basic tasks in signal and image processing. Classical algorithms apply some filtering or regularization techniques, which always incorporate a smoothing of the reconstructed object. This yields good results for distributed and smooth functions/objects but it results in less favourable reconstruction for sparse or stronlg localized objects. Recent developments in applied analysis, in particulaur regularization theory for inverse problems with sparsity constraint, have lead to some new types of algorithms which incorporate shrinkage operations or - mathematically speaking - variational approaches in non-standard function spcaes. This also allows to combine sparse reconstruction methods with indirect measurements, e.g. tomographic or sensor data. The talk will start with discussing an image processing task in 2D mass spectroscopy followed by a short overview of the relevant mathematical theory and the resulting algorithms. The talk finish with some examples from different applications.

	Main Colloquium
Dr. Katherine Blundell	ORATED

University of Oxford, UK

I will describe what can be learned from a single observation of the microquasar SS433 such as symmetric speed variations in its precessing jets and also the distance of SS433 from Earth. I will also show how archival optical spectroscopic data alone show clear deviations from the standard kinematic model, for example with faster jet ejection speeds associated with a smaller precession-cone angle. Additionally, I will show how the archival optical data reveal jet speed oscillations as a function of orbital phase.

	Main Colloquium
Prof. Dr. Thijs de Graauw	ORATED

SRON Groningen and Leiden University

In this talk I will present the Heterodyne Instrument for the Far-Infrared (HIFI) to be launched onboard of ESA’s Herschel Space Observatory, by 2008, with the latest results of the integrated Instrument-Level tests. I will also summarize the HIFI Guaranteed Time key programs that are being prepared by the HIFI consortium. Note: The HIFI instrument is designed to be electronically tunable over a wide and continuous frequency range in the Far Infrared, with velocity resolutions better than 0.1 Km/sec and a high sensitivity. This will allow detailed investigations of a wide variety of astronomical sources, ranging from solar system objects, star formation regions to nuclei of galaxies. The instrument comprises 7 frequency bands, 5 are covering 480-1150 GHz with SIS mixers and two bands cover the 1410-1910 GHz range, with Hot Electron Bolometer Mixers (HEB). The Local Oscillator (LO) subsystem consists of a Ka-band synthesizer followed by 14 chains of frequency multipliers, 2 chains for each frequency band. A pair of Auto-Correlators and a pair of Acousto-Optic spectrometers process the two IF signals from the dual-polarization front-ends to provide instantaneous frequency coverage of 4 GHz, with a set of resolutions (140 KHz to 1 MHz) better than 0.1 Km/s.

	Main Colloquium
Dr. Bernd Vollmer	ORATED

CDS, Observatoire de Strasbourg

The CDS (Strasbourg astronomical data center) services and their current status are presented. The SIMBAD astronomical database provides basic data, cross-identifications and bibliography for astronomical objects outside the solar system. VIZIER provides access to the most complete library of published astronomical catalogues and data tables available on line, organized in a self-documented database. ALADIN is an interactive software sky atlas allowing the user to visualize digitized images of any part of the sky, to superimpose entries from astronomical catalogs or personal user data files. The great advantage of the CDS services is their interoperability, i.e. the three services communicate with each other. This interoperability gives the CDS services a great flexibility, which will allow them to respond efficiently to the requirements of the Virtual Observatory. After the presentation of the services I will give a live demonstration of their capabilities.

	Special Colloquium
Jens Zuther	ORATED

Universität Köln

The new VLT instrument SINFONI gives us a view onto the circum-nuclear properties of AGN at unprecedented detail, even beyond our local Universe. The showcase of the composite galaxy Mrk 609 demonstrates impressively the necessity of adaptive optics assisted integral-field spectroscopy in order to distinguish between Seyfert and starburst characteristics on nuclear scales.

	Special Colloquium
Peter Erni	ORATED

Uni-Bonn

I will give a short introduction to the Inter-Galactic Medium (IGM) and show the importance of studying and understanding the gaseous content of the early Universe. After a short overview of the observation technique of quasar absorption line spectroscopy, I will present three main projects that are each a line of sight toward a high-redshift quasar: (1) Along the line of sight toward the quasar Q0913+072 we detect one of the most metal deficient damped Lyman alpha (DLA) absorption line system ever observed and can link the observed abundance pattern to a metal enrichment by population III stars. (2) The line of sight toward the quasar 004345.8-294733 allows us to confirm/infirm the existence of a so-called Dark Clump. Finally, (3) the line of sight toward the quasar Q0420 -388 shows a very interesting case of two interacting sub-DLA systems at high redshift.

	Main Colloquium
Prof. Dr. Luciano Rezzolla	ORATED

MPI for Gravitational Physics, Albert Einstein Institute, Golm

Recent years have seen a major progress in numerical relativity and the solution of the simplest and yet among the most challenging problems in classical general relativity: that of the evolution of two black holes interacting only gravitationally. I will review the results obtained so far and also the impact these have in gravitational-wave detection, in astrophysics and in cosmology. Finally, I will comment on how to go from a ”knowledge” of the properties of this process to an ”understanding” of the physics of black hole spacetimes.

	Special Colloquium
Prof. Jacques Roland	ORATED

Institut d'Astrophysique, Paris, France

We present a new method to fit VLBI observations of the jet of an AGN (the variations of both coordinates of a VLBI component as a function of time) assuming that the nucleus of the radio source contains a binary black hole system (BBH system). The presence of a BBH system produces two perturbations of the VLBI jet, which are due to the precession of the accretion disk and the motion of the black holes around the gravity center of the BBH system. With a geometrical model of the ejection and - as we use only the VLBI ccordinates - the problem reduces to an astrometrical problem. We deduce the inclination angle of the source and the bulk Lorentz factor of the ejected component. We find that no unique mass for the BBH system providing a best fit exists and discuss the family of solutions producing the same fit.

	Special Colloquium
Thomas Berenz	ORATED

MPIfR Bonn

Im Rahmen des europäischen Forschungsprojekts ”Square Kilometer Array Design Study” wurde für den Europäischen Demonstrator EMBRACE eine koaxiale Übertragungstrecke zur Anbindung der einzelnen Empfangsstationen an eine zentrale Empfängereinheit untersucht. Auf dieser Strecke werden die Hochfrequenz-Signale im Bereich 400MHz bis 1600MHz, Steuersignale im Ethernet Format und die Versorgungsspannung für die Empfangsstationen übertragen. Dazu sollen aus Kostengründen handelsübliche 75 Ohm Koaxialkabel verwendet werden, die erforderlichen Aufschalteinrichtungen wurden in planarer Schaltungstechnik realisiert. Die Arbeit wurde im Rahmen einer Diplomarbeit an der Fachhochschule Koblenz unter der Betreuung von Herrn Prof. Bross realisiert.

	Special Colloquium
Kirsty Rhook	ORATED

University of Cambridge

Supermassive black holes formed as early as one billion years after the big bang, and are ubiquitous in galaxy bulges today. The evolution of supermassive black holes almost certainly played an important role in reionising the universe and shaping the galaxy and quasar populations, yet the origin and growth mechanism of these objects is still unknown. I explore the extent to which up-coming telescopes will probe supermassive black hole growth via accretion and merging, focusing on the detection of HII regions around supermassive black holes at z>6 with LOFAR and the detection of binary black hole coalescence with LISA.

	Special Colloquium
Dr. Carlo Burigana	ORATED

INAF/IASF, Sezione di Bologna

The fundamental concepts of the concordance cosmological model have been largely supported by the recent 3-yr WMAP data that showed with unprecedented evidence the relevance of CMB anisotropies for our understanding of the Universe properties. However, many questions are still open, concerning the geometry, the dark matter and dark energy nature, the properties of primordial fluctuations, the details of cosmological reionization and so on, while the astrophysical information contained in microwave maps appear more and more intriguing. Forthcoming and future experiments, like Planck and, for example, BPOL, will put new light in these fields.

	Special Colloquium
Hyunjoo Kim	ORATED

MPIfR Bonn

Generation of LO power at THz frequencies with conventional techniques is difficult and expensive. I demonstrate steps towards a THz source using the photonic local oscillator technique for submm astronomy. An LT-GaAs photomixer illuminated by two laser signals generates a beat frequency through photoconductive mixing, equal to the difference of two laser frequencies which can be tuned from a few hundred GHz to around a few THz. To generate two frequencies for a photonic LO, I have investigated the use of a Ti:Sapphire ring cavity laser. To generate dual-mode operation in the multi-mode laser, two intracavity solid Fabry-Perot etalons were installed. The spectral width of the beat frequency <10 kHz. The output power from the LT-GaAs photomixer was found to increase linearly with the applied bias voltage. Unexpectedly large fluctuations in the output power were measured, due to dual-mode intensity variations from the Ti:Sapphire ring cavity laser. The reasons are thermal variations of the resonator cavity, mechanical variations, dust particles, air fluctuations, and mode competition. To reduce these power fluctuations, a power stabilization system using volume holographic gratings (VHGs) was developed, which greatly reduced the power fluctuations. Using FLASH and the APEX-2A receivers at the APEX telescope, many molecular transitions toward IK Tau were observed. Thirty four transitions of 12 molecular species, including maser lines, were detected. To determine the spatial distribution of the 12CO(3-2) emission, mapping observations were performed. Assuming local thermodynamic equilibrium (LTE), the rotational temperatures of molecules and the molecular abundances were obtained. By comparing the abundance of the individual molecules to those reported in the literature, we found an improvement over previously available observed abundances. To constrain the physical conditions in the circumstellar envelope, emission from the SO2 and CO molecules were modeled using a Monte Carlo method. From the model fits we could estimate the molecular column density and the kinetic temperature of the envelope.

	Special Colloquium
Laura La Porta	ORATED

MPIfR Bonn

The CMB anisotropies provide us with a unique probe of the early phases of our Universe, including inflationary epoch. The detection of CMB anisotropies relies on precise relies on precise removal of foreground contamination and a substantial improvement over the present state of the art is required to settle some cosmological issues that arose from WMAP and could be addressed by Planck (to be launched in 2008). The Galactic synchrotron emission is the major contaminant over a wide range of frequencies (up to about 70 GHz) and angular scales (larger than about 1 degree), both in total intensity and polarization. I will present the angular power spectrum (APS) analysis of (partially) new radio surveys at 408 MHz and 1420 MHz, that constitute nowadays the best available data for studying this foreground. The work provides a wealth of inputs for the removal of such foreground and has been developed following three main branches: the detailed characterization of the synchrotron emission APS, the evaluation of Faraday depolarization effects, and the estimate of the level of contamination to CMB anisotropy measurements. Finally, I will give a glimpse of new Effelsberg observations at 8.4 GHz aimed at investigating the total intensity-polarization correlation for the foreground.

	Main Colloquium
Dr. Dieter Lutz	ORATED

MPE Garching

ESA’s Herschel Space Observatory, to be launched in 2008, will provide unprecedented sensitivity and spatial resolution for imaging and spectroscopy in the far infrared part of the electromagnetic spectrum. I will describe concept and capabilities of the PACS instrument providing imaging in three bands centered on 75, 110, and 170 micron as well as spectroscopy over the 57-210 micron range. Examples will be given of the scientific potential in a number of fields from star formation research to surveys of galaxy evolution.

	Special Colloquium
Dr. Emmanouil Angelakis	ORATED

MPIfR

The point radio sources comprise one amongst the major contaminants of the Cosmic Microwave Background radiation. Consequently, they possess a significant potential for causing severe distortion of the information imprinted in its anisotropies. They demand therefore some sort of treatment that usually boils down to removing contaminated pixels in any CMB experiment. As a support to the Cosmic Background Imager (CBI) we have carried out intensive observations of a sample of nearly 6000 NVSS sources that happen to be in the targeted fields at two frequencies (4.85 and 10.45 GHz) with the 100-m telescope at Effelsberg. The objective has been the estimation of the flux density that each one of them could contribute at the central frequency of the CBI (31 GHz) on the basis of their three-point radio spectral index and their 1.4-GHz flux density as extracted from the NVSS catalogue. However, the compilation of such an extended data base of multi-frequency measurements gives handle for a series of further studies. First, we exploit the sample in order to compute the source counts at different frequencies. That provides the opportunity for comparison with direct surveys at those wavelengths and more importantly with the theoretical predictions. Practically, this can assist the computation of the confusion limits that set a physical limit to the reachable sensitivity of radio instruments. Further, the computed spectral indices have been used to trace candidates for GHz-Peacked Spectrum sources and their extreme sub-class of High Frequency Peakers that are believed to be the early evolutionary stages of radio activity. Additionally, although the observations have been designed to be time-efficient we manage to carry some polarization studies. Finally, the weakness of the anisotropies in terms of brightness temperature has forced the goal of reaching levels of only a few mJy. That became possible only with the deep understanding of the system and the development of new case-dependent methods and tools of analysis. The most important points of those matters will be presented and discussed as coherently as possible.

	Special Colloquium
Jan Forbrich	ORATED

MPIfR Bonn

Already in very early stages of star formation, high-energy processes are occuring. These can be observed in X-rays or in nonthermal, e.g. gyrosynchrotron, radio emission. In order to learn more about these processes, I studied the multi-wavelength variability of very young protostars in the Coronet cluster, partly in coordinated simultaneous observations. Additionally, the Coronet cluster and its X-ray properties were characterized based on one of the deepest X-ray datasets ever obtained of a star-forming region. With the aim of resolving peristellar magnetic structure around protostars, sensitive VLBI observations were obtained of a few selected sources. In separate projects, also radio variability of Young Stellar Objects was studied, namely for a deeply embedded source in the Orion-KL star-forming region and for the V773 Tau multiple system. Finally, I attempted to study the role of magnetic fields in even earlier evolutionary stages of star formation by millimeter polarimetry of molecular clouds in search of the so-called Goldreich-Kylafis effect.

	Main Colloquium
Prof. Bernhard Brandl	ORATED

Sterrewacht Leiden

Spitzer is one of NASA’s four Great Observatories covering the infrared portion of the electromagnetic spectrum with to date unsurpassed sensitivity. As such it is perfectly suited to the study of local and distant starbursts. In my talk I will discuss the global properties of starburst in the infrared, based on spectroscopy of a large sample of starburst galaxies. The importance of spatial resolution for these studies will be illustrated with recent Spitzer data on three well-known objects: 30 Doradus, M82 and the Antennae.

	Special Colloquium
Dr. Genevieve Parmentier	ORATED

Astronomisches Rechen-Institut, Heidelberg

Evidence favouring a Gaussian initial globular cluster mass function similar to that observed today has accumulated over recent years. I investigate how the shape of the initial cluster mass function is affected by expulsion from the protocluster of the leftover star forming gas due to supernova activity. Owing to the weakening of its gravitational potential, the protocluster retains a fraction only of its newly formed stars. The mass fraction of bound stars extends from zero to unity depending on the star formation efficiency achieved by the protoglobular cloud. Such wide variations may affect the mapping of the protoglobular cloud mass function to the resulting initial globular cluster mass function. I show that a bell-shaped cluster mass function with the observed width and the right turnover may be the imprint of the gas removal phase, provided that the protoglobular clouds have a characteristic mass of about 10^6 Msol.

	Special Colloquium
Dr. Peter Schilke	ORATED

MPIfR

The Atacama Large Millimeter Array is a new millimeter/submillimeter interferometer in the Chilean Andes. It will work in the millimeter/submillimeter range and, due to its size (50 12m antennas) and superior site (altitude 5000 m in the Atacama desert) be a quantum jump in capabilities with respect to existing arrays. It will make a significant impact in almost all areas in astronomy, particularly in studies of galaxy and star formation. ALMA grew out of long-standing planning of such arrays in North America (MMA Project), Europe (LSA Project) and Japan (LMA Project) through merging, and is a true world array. Its construction has been started this year, and it is scheduled to be completed by 2012. Since the project has now settled down to a well defined state, it is about time to give a status update. In this talk, I will describe the science ALMA will do, put in the context of other instruments existing or planned. Then, I’ll give an update on the actual implementation, capabilities and the current schedule of the project.

	Main Colloquium
Prof. Dr. Felix Aharonian	ORATED

DIAS/Dublin and MPIK/Heidelberg

I will highlight the recent exciting results obtained in the very high energy gamma-ray regime with the HESS array of atmospheric Cherenkov telescopes and discuss their astrophysical and cosmological implications. I also will briefly discuss the major motivations and objectives of the next generation ground-based gamma-ray detectors.

	Special Colloquium
Dr. Georges Meynet	ORATED

Observatoire de Geneve

We discuss how the inclusion of the effects of rotation in massive star models improves the agreement with the observations: surface enrichments, massive star populations at different metallicities are much better fitted when rotation is accounted for. Rotation has also a deep impact on stellar nucleosynthesis, especially at low metallicity. In particuliar, rotating massive stars appear to be important sources of primary nitrogen and may lose through stellar winds, even at very low metallicity, an important fraction of their initial mass. This may have interesting consequences for explaining the extremely metal poor carbon-rich stars, the very rich helium stars found in globular clusters, as well as the Na-O, Mg-Al anticorrelations observed in these clusters. We shall also present new results concerning the progenitors of the soft long Gamma Ray Bursts.

	Informal Colloquium
Dr. Padelis Papadopoulos	ORATED

MPIfR

I will report on recent results on high-J CO and HCN observations of the ULIRG/QSO Mrk 231 and implications for the dense molecular gas cooling budget and the detections of such lines from starbursts at high redshifts.

	Main Colloquium
Dr. Padelis Papadopoulos	ORATED

MPIfR

I will report on recent numerical models of galaxies that follow the stellar and gaseous content of galaxies using a hybrid N-body/hydrodynamic code and incorporate the formation and evolution of the molecular hydrogen phase for the first time. This gas is the “true” fuel of star formation in galaxies and in turn H2 formation turns out to be a powerful and hitherto neglected regulator of star formation. Finally such numerical models pave the way for their comparisons to the copious datasets for the H2 distribution in galaxies that will become routine in the next decade.

	Informal Colloquium
Dr. Richard Dodson	ORATED

Observatorio Astronomico Nacional, Yebes, Spain

The HALCA satellite, which provided the Space baseline for the VLBI Space Observing Project (VSOP), was launched in Feb 1997 and the last operational command was sent in November 2005; waving adios with the downlink antenna. The last Survey observations were made in October 2003. The analysis of the Survey data has only just been completed. I will present a review of the total results, and discuss future aspects in view of the planned VSOP-2 mission. As a specific example the results of a pentachromic analysis of the Survey source VS01A (a.k.a. M87) are presented, which allowed the solution for the magnetic field structure in the VLBI jet and inner core region.

	Special Colloquium
Prof. William Forman	ORATED

Center for Astrophysics, Boston

We discuss the interaction of supermassive black holes with cluster and early type galaxy environments. Hot gas, the dominant baryonic component in clusters but also found in early type galaxy coroane, provides a record of activity of AGN/supermassive black holes within hot gas rich systems. For clusters, the hot gas shows evidence of shocks and buoyant bubbles of relativistic plasma, both produced by supermassive black hole outbursts. In addition, filamentary structures seen in the X-ray gas distribution show a complex relation between the AGN produced plasma and the thermal gas. We focus on the Chandra observation of M87 and other clusters that show evidence for outbursts with energies up to 10^{62}ergs. Observations from a survey of 160 “normal” early type galaxies also will be presented. Chandra images of these galaxies show the presence of nuclear emission, jets, cavities and buoyant bubbles in their hot coronae, similar to those found in clusters. For those galaxies with luminous gaseous coronae, 30% show cavities from which we compute outburst energies of 10^{55} to 10^{59}ergs and outburst ages of 1-100 million years. We detect weak active nuclei (luminosities from 10^{38} to 10^{41}erg/sec) in 80% of the galaxy sample. We compare the effects of outbursts on hot coronae and the growth of the black holes in systems from galaxies to rich clusters.

	Special Colloquium
Prof. Craig Sarazin	ORATED

University of Virginia, Charlottesville, USA

Observations with the Chandra X-ray Observatory of a large sample of elliptical galaxies in the Virgo cluster will be discussed, as well as repeated long observations of the nearby X-ray faint elliptical NGC4697. The Chandra observations resolve the X-ray content of nearby early-type galaxies into low-mass X-ray binaries (LMXBs) and diffuse interstellar gas. The sim50–200 bright LMXBs present in each early-type galaxy are complementary to the sample of Milky Way LMXBs. The X-ray luminosity functions of LMXBs in early-type galaxies generally have a knee or break at about 2cdot 10^{38}erg/s, which is approximately the Eddington luminosity for a 1.4M_odot neutron star. This suggests that the LMXBs with higher luminosities generally contain accreting black holes. Multi-epoch observations of NGC4697, one of the nearest, massive early-type galaxies whose X-ray emission is LMXB-dominated, reveal sources with extreme flaring on minutes to hour timescales and sources variable on days to years timescales. The luminous flares may be associated with micro-blazars: X-ray binaries with accreting black holes with jets which are pointed in our direction. Comparisons of the positions of the LMXBs and globular clusters (GCs) from Hubble Space Telescope observations have shown that a high fraction of the LMXBs are associated with GCs. The fraction of LMXBs associated with GCs increases along the Hubble sequence from spiral bulges to S0s to Es to cDs. On the other hand, the fraction of globular clusters which contain X-ray sources appears to be roughly constant (sim4% at L_{mathrm{X}} sim 10^{38}erg/s; sim10% at L_{mathrm{X}} sim 10^{37}erg/s) from galaxy to galaxy. X-ray sources are associated preferentially with optically luminous and massive GCs, with redder, more metal-rich GCs, and with more compact GCs. I show that the probability that a GC has a LMXB depends on the stellar encounter rate in the GC and on its metallicity. The dependence on the stellar encounter rate provides the the most direct evidence to date that the formation of LMXBs in GCs is due to the stellar interactions.