The discovery of a population of massive, compact and quiescent early-type galaxies has changed the view on plausible formation scenarios for the present day population of elliptical galaxies. Traditionally assumed formation histories dominated by 'single events' like early collapse or major mergers appear to be incomplete and have to be embedded in the context of hierarchical cosmological models with continuous gas accretion and the merging of small stellar systems (minor mergers). Once these processes are consistently taken into account the hierarchical models favor a two-phase assembly process and are in much better shape to capture the observed trends. We review some aspects of recent progress in the field.

We use the adaptive mesh refinement code RAMSES to model the formation of protoplanetary disks in realistic star formation environments. The resolution scales over up to 29 powers of two (~ 9 orders of magnitude) covering a range from outer scales of 40 pc to inner scales of 0.015 AU. The accretion rate from a 1.5 solar mass envelope peaks near 10−4 M⊙ about 6 kyr after sink particle formation and then decays approximately exponentially, reaching 10−6 M⊙ in 100 kyr. The models suggest universal scalings of physical properties with radius during the main accretion phase, with kinetic and / or magnetic energy in approximate balance with gravitational energy. Efficient accretion is made possible by the braking action of the magnetic field, which nevertheless allows a near-Keplerian disk to grow to a 100 AU size. The magnetic field strength ranges from more than 10 G at 0.1 AU to less than 1 mG at 100 AU, and drives a time dependent bipolar outflow, with a collimated jet and a broader disk wind.

We discuss a number of topics relevant to disk-magnetosphere interaction and how numerical simulations illuminate them. The topics include: (1) disk-magnetosphere interaction and the problem of disk-locking; (2) the wind problem; (3) structure of the magnetospheric flow, hot spots at the star's surface, and the inner disk region; (4) modeling of spectra from 3D funnel streams; (5) accretion to a star with a complex magnetic field; (6) accretion through 3D instabilities; (7) magnetospheric gap and survival of protoplanets. Results of both 2D and 3D simulations are discussed.

The ALFA mission is designed to map the entire sky at frequencies between approximately 0.3 and 30 MHz with angular resolution limited by interstellar and interplanetary scattering. Most of this region of the spectrum is inaccessible from the ground because of absorption and refraction by the Earth’s ionosphere. A wide range of astrophysical questions concerning solar system, galactic, and extragalactic objects could be answered with high resolution images at low frequencies, where absorption effects and coherent emission processes become important and the synchrotron lifetimes of electrons are comparable to the age of the universe.

Most of the baryons in the universe remain undetected. They are thought to be floating in intergalactic space, and their thermal state is highly uncertain. The only places where we have reasonably complete observations of the overall baryon population are in clusters of galaxies, where the baryons reveal themselves through their X-ray emission. There we find that only about 10% of the baryons have turned into stars, probably because feedback processes intervene to prevent more baryons from condensing. These galaxy formation processes seem to have left an imprint on the thermal state of the intracluster medium, but in order to interpret that imprint, one needs to pay close attention to how entropy develops in the intergalactic gas. Many of the global properties of clusters turn out to be determined primarily by the entropy threshold for cooling within a Hubble time. However, XMM-Newton observation are revealing a sort of altered similarity among the entropy profiles of clusters seeming to indicate that galactic winds may have smoothed the local intergalactic medium before it accreted onto clusters.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Our research has focused on the measurement of the electronic spectra of unstable molecules which are presumed to be of relevance to astrophysical observations. Among these are the carbon chains and their ions. Thus we have been using and developing a number of spectroscopic methods to determine their spectra in the gas phase, including absorption via cavity ring-down and REMPI methods. The species are produced in supersonic jets coupled with discharge and laser ablation sources. With the successful laboratory detection of the electronic spectra of a number of key species, such as bare carbon chains Cnn=4,5, comparisons with astrophysical data could be made which lead to interesting implications for the future search for the species which could be responsible for the diffuse interstellar bands. Among the recent relevant observations in the laboratory have been the electronic spectra of carbon rings, Cnn=14,18,22, the development of a method to study transitions in mass-selected ions collisionally relaxed to 20 K and held in a 22-pole radiofrequency trap, and the study of metal containing carbon chains.

Radio interferometric observations of extragalactic radio sources have been made with antennas at the Haystack Observatory in Massachusetts and the Owens Valley Radio Observatory in California during fourteen separate experiments distributed between September 1976 and May 1978. The components of the baseline vector and the coordinates of the sources were estimated from the data from each experiment separately. The root-weighted-mean-square scatter about the weighted mean (“repeatability”) of the estimates of the length of the 3900 km baseline was approximately 7 cm, and of the source coordinates, approximately or less, except for the declinations of low-declination sources. With the source coordinates all held fixed at the best available, a posteriori, values, and the analyses repeated for each experiment, the repeatability obtained for the estimate of baseline length was 4 cm. From analyses of the data from several experiments simultaneously, estimates were obtained of changes in the x component of pole position and in the Earth's rotation (UT1). Comparison with the corresponding results obtained by the Bureau International de l'Heure (BIH) discloses systematic differences. In particular, the trends in the radio interferometric determinations of the changes in pole position agree more closely with those from the International Polar Motion Service (IPMS) and from the Doppler observations of satellites than with those from the BIH.

From the analysis of VLBI observational data compiled by USNO (U.S. Naval Observatory) from MJD 44089.994 to 51618.250 (McCarthy, 2000), we showed that a strong peak around –400 sidereal days in the spectrum of its differences from the IERS96 nutation theory could be explained by adding a model Free Core Nutation (FCN) term in the form of a single damped oscillation. Then we developed a new analytical theory of the nonrigid-Earth nutation including the derived FCN model. We adopted RDAN98 (Roosbeek and Dehant, 1998) as the rigid Earth nutation theory. It was convolved with a transfer function using numerical convolution in the time domain (Shirai and Fukushima, 2000). The form of the transfer function was the same as that of Herring (1995). However, its free parameters such as the complex amplitude and frequency of the FCN were readjusted by fitting to the above VLBI data. Even after truncating the forced nutation series so as to contain only 180 terms, the WRMS (Weighted Root Mean Square) of the complex residuals for the new nutation series is 0.312 mas, which is significantly smaller than 0.325 mas, that of the IERS96 nutation theory. As for the FCN term, we estimated its oscillatory period as –430.8±0.6 sidereal days, and its Q-value as 16200 ± 1600. Also we estimated the correction of the precession constants as −0.29297±0.00047”/cy in longitude and −0.02430±0.00019”/cy in obliquity, respectively.

We present Zeeman-Doppler images of the active K2 star II Peg for the years 2004 and 2007. The surface magnetic field was reconstructed with our new ZDI code iMap which provides a full polarized radiative transfer driven inversion to simultaneously reconstruct the surface temperature and magnetic vector field distribution. II Peg shows a remarkable large scale magnetic field structure for both years. The magnetic field is predominantly located at high latitudes and is arranged in active longitudes. A dramatic evolution in the magnetic field structure is visible for the two years, where a dominant and largely unipolar field in 2004 has changed into two distinct and large scale bipolar structures in 2007.

It has been a long standing problem in astrochemistry to explain how molecules can form in a highly dilute environment such as the interstellar medium. In the last decennium more and more evidence has been found that the observed mix of small and complex, stable and highly transient species in space is the cumulative result of gas phase and solid state reactions as well as gas-grain interactions. Solid state reactions on icy dust grains are specifically found to play an important role in the formation of the more complex “organic” compounds. In order to investigate the underlying physical and chemical processes detailed laboratory based experiments are needed that simulate surface reactions triggered by processes as different as thermal heating, photon (UV) irradiation and particle (atom, cosmic ray, electron) bombardment of interstellar ice analogues. Here, some of the latest research performed in the Sackler Laboratory for Astrophysics in Leiden, the Netherlands is reviewed. The focus is on hydrogenation, i.e., H-atom addition reactions and vacuum ultraviolet irradiation of interstellar ice analogues at astronomically relevant temperatures. It is shown that solid state processes are crucial in the chemical evolution of the interstellar medium, providing pathways towards molecular complexity in space.

Camera networks for the study of bright fireballs now have a history approaching two decades• It was hoped that the networks would produce a statistically significant group of recovered meteorites with accurate orbits. Due to the great difficulty in locating the meteorites from a photographed event, there are still only three meteorites with orbits determined from suitable photographs; Pribram, Lost City and Innisfree (Ceplecha I96I, McCrosky et al. 1971, Halliday et al. 1978, respectively). Networks do, however, provide an alternative approach to the problem. Instead of determining approximate orbits from visual observations of recovered meteorite falls, it is now preferable to use reliable orbits from the camera networks for fireballs which are believed to have dropped meteorites that could not be located, or, that are believed to have been physically identical to meteorites, although no appreciable mass survived the atmospheric flight. This paper will review current knowledge based on this approach to the problem.

We present infrared photometry of LMC stars taken from a region of 2.5° in right ascension from the DeNIS (Deep Near Infrared Southern Sky Survey) survey.

A damped random walk is a stochastic process, defined by an exponential covariance matrix that behaves as a random walk for short time scales and asymptotically achieves a finite variability amplitude at long time scales. Over the last few years, it has been demonstrated, mostly but not exclusively using SDSS data, that a damped random walk model provides a satisfactory statistical description of observed quasar variability in the optical wavelength range, for rest-frame timescales from 5 days to 2000 days. The best-fit characteristic timescale and asymptotic variability amplitude scale with the luminosity, black hole mass, and rest wavelength, and appear independent of redshift. In addition to providing insights into the physics of quasar variability, the best-fit model parameters can be used to efficiently separate quasars from stars in imaging surveys with adequate long-term multi-epoch data, such as expected from LSST.

A brief description of the QuantEYE instrument proposed as a focal plane instrument for OWL is given. This instrument is dedicated to the very high speed observation of many active phenomena with a photon counting capability of up to 1GHz. The system samples the beam in 10$\times$10 subpupils, each focused on a fast photon counting detector.

I have developed a new opacity-sampling version of my model atmosphere program called ATLAS12. It recognizes more than 1000 atomic and molecular species, each in up to 10 isotopic forms. It can treat all ions of the elements up through Zn and the first 5 ions of heavier elements up through Es. The elemental and isotopic abundances are treated as variables with depth. At present ATLAS12 reads atomic line data from Kurucz CD-ROM 1 and diatomic molecular data from Kurucz CD-ROM 15. For each line the wavelength, identification, lower energy level, gf, radiative, Stark, and van der Waals damping constants are packed into 16 bytes. At each wavelength point in a frequency integration the Voigt profiles of all the significant nearby lines are computed and summed. The H, He, and auto-ionizing lines are treated with the appropriate profile functions.

The fluxes predicted by ATLAS12 are not accurate in intermediate or narrow bandpass intervals because the sample size is too small. A special stripped version of the spectrum synthesis program SYNTHE is used to generate the surface flux for the converged model using the line data on CD-ROMs 1 and 15. That high resolution spectrum can be used directly or can be instrumentally broadened to compare to low resolution observations.

ATLAS12 can be used to produce improved models for Am and Ap stars. It should be very useful for investigating diffusion effects in atmospheres. It can be used to model exciting stars for H II regions with abundances consistent with those of the H II region. These programs and line files will be distributed on CD-ROMs.

This paper explains the structure and organization of the International Commission on Illumination (CIE), shows how it works, and describes its objectives and achievements. It gives details on the technical work done in the CIE Divisions and Technical Committees, and mentions some examples of the work in progress, emphasising those in connection with the subject of this conference. Quality lighting is the key to reducing light pollution. CIE is aware of the problem and takes it very seriously. CIE Divisions are working on problems such as glare, quality lighting, light trespass, light pollution and energy efficiency. In this endeavour CIE is also co-sponsoring this conference.

In a Joint Discussion devoted to the ages and kinematics of the local stars, inclusion of a paper on the local gas may seem anomalous. There is, however, strong justification for considering such a topic. Newly formed stars retain many properties of the gas from which they originated. To understand the spatial and kinematic properties of local young stars, we must understand the spatial distribution and the kinematics of the local gas from which they were formed.

A cloud within the interstellar gas can collapse gravitationally if its mass, density, and temperature satisfy the Jeans Criterion. Collapse is favored by low temperature and high density.

Various investigators have pointed out that in the Lin Spiral Density Wave Theory a shock must occur on the inner edge of a spiral arm. Such a shock compresses the gas and hence promotes cloud formation with subsequent gravitational collapse to form stars. Shu and several collaborators have shown that such a shock is very effective in triggering cloud formation in a two-phase interstellar medium of the type discussed by Field et al. (1969), and it is widely believed that this is the principal step in the process of forming stars.

Theoretical as well as observational aspects of the s-process nucleosynthesis are reviewed. The classical site-independent s-process model as well as the s-process in massive stars are shortly described. A special attention is paid to the nucleosynthesis taking place in AGB stars and the extra-mixing invoked to explain the production of neutrons in the C-rich layers during the interpulse. We also discuss the nucleosynthesis found in hot AGB stars for which the s-process during the interpulse phase is inhibited, but the one resulting from the large temperatures in the thermal pulse is boosted. We comment on the uncertainties affecting our understanding of the physical mechanisms responsible for a successful s-process. Finally, various types of spectroscopic observations of s-process elements are discussed.

The anticorrelation of C and Si previously inferred from high-resolution spectroscopy of sharp-lined A stars classified as normal or mild Am is also found among the metal-deficient, more rapidly rotating λ Boo stars. The entire sample of program stars covers the range [C/Si] = − 1.14 (Sirius, mild Am star) to + 1.35 (HR 7400, λ Boo-type). Iron varies parallel with silicon. With respect to surface chemistry the λ Boo stars do not form a distinct group but rather represent the lower end in a continuous sequence of ‘metal’ abundance extending over more than 1.5 dex.

We argue that differential accretion of gas and dust in late stages of star formation or during the main-sequence phase is responsible for most of the abundance variations of the lighter elements up to the iron group. Enhanced or impeded accretion of dust leads to a metal-rich or metal-poor surface composition, respectively. The heavy trace elements Sr and Ba show additional anomalies indicating that other processes like gravitational and radiative separation are also involved.

The condensation of gas-phase molecules onto grain surfaces in cold molecular clouds is widely expected, and the presence of the resultant icy mantles well established, but quantitative study of the gas-phase depletions has not proved easy. This paper reviews the methods for determining depletions and the associated problems. Further observations are critical to testing our expectations for depletions and for the chemical evolution of forming stellar systems.