Until recently, there has been no available method  for quantizing the superstring in which all d=10 super-Poincare invariance is manifest. This has hampered efforts to understand perturbative  finiteness of superstring amplitudes and to study the superstring in Ramond-Ramond backgrounds. 
Over the last three years, a new formalism has been developed for quantizing the superstring using pure spinors in which all super-Poincare invariance is manifest. After reviewing the problems with other formalisms for the superstring, this new pure spinor formalism will be described and various applications will be discussed.

The effort to detect gravitational waves has increased steadily in recent years. More than 20 major projects in gravitational wave detection are underway around the world. They span the spectrum from below 10^-6 Hz to above 10⁴ Hz. Detectors can be divided into two categories: those that use resonant masses and those that use electromagnetic beams. For electromagnetic beams the approaches vary according to the frequency band. In the microhertz band the timing of pulsar signals offers the possibility of detecting the coalescence of massive black holes during galactic mergers. In the millihertz band nemerous galactic binary star sources plus extragalactic mergers should be detectable using space laser interferometry. Smaller scale space laser techniques could also be used in the band around 1Hz. In the audiofrequency band terrestrial laser interferometers should detect signals associated with stellar mass compact objects, particularly neutron star births and coalescences. Resonant mass detectors in the form of bars and spheres offer high sensitivity in the 1-10kHz range. 
This talk will present an overview of the field emphasising the present experimental efforts and the future projects which will make gravitational wave astronomy a reality.

After a brief introduction on frame-dragging and gravitomagnetism in general relativity, we describe the experimental efforts to measure frame-dragging and to detect the Lense-Thirring effect using satellite laser ranging. We finally describe the "Spin-Time-Delay", i.e. the time delay in the travel time of photons due to the spin of a body both inside a rotating shell and outside a rotating body, and the prospects to observe it.

I will desribe some of the recent developments in string compactifications using duality twists and fluxes that can be used to stabilize the string moduli.

Bolometric detectors feature outstanding sensitivity to the CMB and to the faint proto-structures present in the last scattering surface at redshift 1000. Using Bolometers, BOOMERanG has provided the first image where the CMB structure at sub-horizon scales has been resolved. Such image compares well to the recent images of the CMB at longer wavelengths from the WMAP satellite.
The current trend in CMB research with bolometers is towards the measurement of CMB polarization, the detection of the SZ effect in clusters, and the study of primeval galaxies. I'll review the current status of these efforts, including preliminary results from the recent polarization flight of BOOMERanG, and finally outline the HFI instrument on Planck, and its potential for cosmology.

Studies of the early phases of structure formation, including the first  stars, protogalaxies, and the first massive black holes, are now on the  forefront of astrophysical cosmology. As the first sources form, their  UV light reionizes the universe, ending the "dark ages" which follow the  cosmic recombination, and ending with a "cosmic renaissance" at the epoch  of ~ 0.5 to 1 Gigayears after the Big Bang. Objects powered by black  holes may provide especially useful probes of this fundamental cosmological  era. Formation of the first luminous quasars (i.e., their central massive  black holes) and their host galaxies and larger structures now seem to be  profoundly connected. Such luminous quasars can be used to probe the  early structure and evolution of the intergalactic medium at the end of  the reionization era. At a smaller mass scale, there are growing reasons  to believe that the first generation of stars were very massive. Their  explosions could have lead to the formation of stellar-mass black holes,  and thence to high-redshift gamma-ray bursts. Studies of such primordial  gamma-ray bursts can provide a unique probe in the early stages of galaxy formation, chemical enrichment, and the physics of the first stars.

The emission of additional massless degrees of freedom which are present in many braneworld scenarios leads to a modification of Einstein's quadrupole formula. After a general introduction, I present the the induced change from the 'gravi-scalar' for the binary pulsar PSR~1913+16 where it amounts to about 20%, by far excluded by present experimental data.

Overview of recent deep sky surveys is given: Las Campanas Redshift Survey, 2 degree Field Survey, Sloan Digital Sky Survey, Distant Supernova Project. Luminosity density field has been determined for 6 slices of the LCRS and 2 equatorial slices of SDSS using a cell size 1 Mpc/h, and Gaussian smoothing with dispersions 0.8 and 10 Mpc/h. High-resolution fields have been used to construct catalogues of density peaks - density field clusters of galaxies, taking into account selection effects due to limited interval of apparent magnitudes in observing galaxy redshifts. The low-resolution density fields have been used to find superclusters of galaxies, and to characterize the large-scale environment of clusters. The analysis shows that there exists a pronounced relationship between the luminosity and morphological type of galaxies and clusters of galaxies and the environmental density. In high-density regions galaxies and clusters are more luminous by a factor up to 10; in in low-density regions late type galaxies dominate, in high-density regions early type galaxies dominate, but late type galaxies are also present. Morphological structure (the shape of superclusters and filaments of galaxies) in superclusters and galaxy systems in large low-density regions (supervoids) is similar, only in superclusters clusters and cluster filaments are richer and their morphological type more late. Similar dependence on the density of the environment is observed in numerical models of structure evolution. Comparison of results of deep galaxy surveys with results from distant supernovae project and CMB data shows that we live in a critical density universe dominated by the cosmological constant (dark energy).

We review the current status of Ultra High-Energy Cosmic Rays (UHERC), discussing the recent controversy on the existence or absence of a GZK  cut-off. After briefly reviewing possible candidate sources for UHECR, astrophysical and from new particle physics, we give a presentation of the Auger Observatory now under construction in Argentina, finishing up with future projects, beyond Auger.

The LIGO interferometers are currently alternating between taking of science data and further commissioning to bring the noise down to the design level. The current sensitivity and bandwidth of these interferometers is the best achieved in a working detector. The state of the detectors and commissioning progress will be discussed. Analysis of the data from the first science run is nearly complete and plans are being developed for more detailed studies coming out of the second science run. Preliminary results with this groundbreaking data will be presented. Plans for the future advanced LIGO interferometers and the gravitational astronomy that these detectors will allow will also be described.

A supersymmetric solution is one admitting Killing spinors, so that it is invariant under a super-isometry group. Recent progress in this area is reviewed, including recently found classes of solutions such as plane wave solutions and high-dimsensional analogues of the Godel solution.
The plane wave solutions arise from Penrose limits, and have played a special role in understanding the holographic duality between quantum gravity and gauge theory. Mathematical aspects including generalised holonomy, G-structures and callibtrations are discussed.

The Gravity Probe B satellite is now being moved to the Vandenburg Air Force Base in preparation for the launch on a Delta II rocket, which is planned for November 13 of this year. With the satellite in its 640km polar orbit, the precession rates of four cryogenic, electrostatically-supported gyroscopes will be measured and compared to the geodetic and frame-dragging precession predicted by the general theory of relativity. The experiment has been designed to reduce not only the classical systematic errors but also the classical effects themselves to a level smaller than the overall experimental error. This experimental design has placed demanding requirements on the satellite, the gyroscopes, and the instrumentation used to measure the precession of the gyroscopes relative to the guide star, IM Pegasai (HR 8703). Measurement of the properties of the components and tests of the integrated system have demonstrated that the flight hardware meets or, in many cases, exceeds these requirements. Based on these results, the expected statistical and systematic experimental errors will be smaller originally anticipated.

The evolution equations of the Lemaitre-Tolman model are reformulated in such a way that both the initial and final state become input data. The initial state may be defined either by a density distribution or by a velocity distribution of matter at t_1. The final state may be defined by any of these distributions at t_2 > t_1. For each possible pair of distributions we proved that a unique Lemaitre-Tolman model exists that evolves one into the other. Then we gave several numerical examples in which we assumed t_1 = recombination epoch and t_2 = today. The initial distribution was within the constraints imposed by observations of the CMB radiation (10^{-5} for the relative density amplitude, 10^{-4} for the relative velocity amplitude), while the final distribution modelled a modern structure such as (1) a galaxy cluster, (2) a void, or (3) a galaxy with a central black hole. We were sucessful in cases (1) and (3) (although, strictly speaking, at those angular scales there are no observational data on the CMB anisotropies). With voids, the final structure turned out to be highly sensitive to the profile, not just to the amplitude of the initial inhomogeneity, and so far we have not identified the optimal profile. Because of spherical symmetry, we cannot take rotation into account, and so our models are not fully realistic. However, the method should carry over to more general exact cosmological models once they are found.

Since a Japanese 300-m length interferometric gravitational wave detector TAMA300 became operational in 1999, eight observation runs have been performed. In the sixth and eighth runs, called Data Taking 6 (DT6) and Data Taking 8 (DT8) respectively, the observation data for more than 1000 hours were obtained. The results of DT6 data analyses as well as the operational status and the preliminary results for DT8 will be presented.

In the past, they were recognized as the most destructive force in nature. Now, following a cascade of astonishing discoveries, supermassive black holes have undergone a dramatic shift in paradigm---these objects may have been critical to the formation of structure in the early universe, spawning bursts of star formation and planets. As many as 200 million of them may now be lurking through the vast expanses of the observable cosmos. The most accessible among them appears to be lurking at the Center of Our Galaxy. In this talk, we will examine the evidence that has brought us to this point, and we will see why the astrophysical community is now looking with great anticipation to the imminent breakthroughs that will permit us to see the shadow of a black hole within this decade.

I will review the observation of relativistic jets in astrophysical black  holes with particular emphasis on microquasars. These are stellar-mass  black holes in our own Galaxy that mimic, on a smaller scale, many of  the phenomena seen in quasars. Their discovery has open the way for  a new understanding of the connection between accretion of matter onto  black holes and the origin of relativistic jets. I will review the  open questions and future perspectives in this new field of research.

We study various aspects of the cohabitation between these two sciences. In the British tradition, theoretical physics is Mathematics. The history of their growth is one of mutual fertilization, with either discipline exploiting the other’s results. Relativity provides our first example. Einstein’s Special Theory of Relativity was done without any suspicion of a geometical foundation, until Minkowski read the pattern. This would have had no continuation if It were’nt for its resolution ofthe timely problem created by the attempt at a SR+ Newtonian Mechanics compromise; with Grossmann’s role of catalist, General Relativity became a Geometrical theory with ongoing fruitful injections from the work of Gauss and Riemann in Maths. Our second example is the sequence provided by the Yang-Mills Fibre Bundle and its applications. My third example is extracted from personal experience n my 40 years collaboration with S. Sternberg (he is ‘our’ Marcel Grossmann though I am unfortunately no Einstein)

We deal with the problem of "focalization".
Roughly speaking we are interested in describing how the solutions of a second order differential equation passing through a point P will meet again i.e. focus afterwards at another point Q, with the elapsing of the same time.
This is formalized first in the case of a second order Ordinary Differential Equation defined in Euclidean space and then extended to the case of geodesics of a complete Riemann manifold.
The resulting concept of Focal Decomposition then relates naturally to the semiclassical quantization via the Feynmann path integral method, to the Brillouin zones of a crystal and to the arithmetic theory of quadratic forms.

In light of the recent breakthrough of GRB030329/SN2003dh, I will re-examine the case of GRB980425/SN1998bw and present new XMM-Newton observations in conjunction with previous BeppoSAX observations of the field. Implications for GRB/SN connection and X-ray supernova emission will be outlined.

In the past few years, there has been an increasing interest on bouncing cosmological models. In this talk, I first describe the conditions for the occurrence of bounces in the far past of the Standard Cosmological Model. I enumerate the matter models and theories containing General Relativity in which these conditions can be fulfilled. Then, I describe the evolution of cosmological perturbations in such bouncing models. I discuss how a scale invariant spectrum of perturbations can be obtained in this framework, and whether it is possible to verify observationally if our Universe has ever experienced a bounce. Finally, I make a critical comparison between bouncing and usual inflationary models.

Search of coincident signals obtained with the gravitational wave detectors EXPLORER and NAUTILUS during the years 1998 and 2001 has been performed. Results are presented, showing indication of coincidence excess at times when the detectors are favourably oriented with respect to the Galactic Disk.

Following the three paradigms for the interpretation of GRBs published in Astrophysical Journal Letters (Vol. 555: L107, L113, L117), we illustrate the space-time parametrization, the luminosities in fixed energy bands, the spectra and the time variability of GRB991216 chosen as a prototype. This result is obtained fixing the only three free parameters of the EMBH model for GRB. We then apply the same model to GRB980425 and SN1998bw, obtaining the detailed description of the GRB source as well as the induced supernova event giving rise to SN1998bw. It is proposed that a neutron star, born from the induced supernova event, is observed in this unprecedented astrophysical "tryptic". We then summarize the application of the EMBH model to GRB030329/SN2003dh and to GRB970228 and the associated Supernova. Some inferences on the GRB-Supernova phenomenon are presented. It is shown that the GRB is either triggering the induced supernova event or that the GRB and the Supernova are triggered by the same relativistic process. In no way the GRB can be considered originating from the Supernova.

Paranal observatory, the home of the VLT and  VLTI facilities, will be described. The facility which  operates four 8.2-m telescopes and their instrumentation  as well as near future enhancements will be discussed. The  operational models which include service observing and  the oportunities for non-observational astronomers to  exploit the facility will also be addressed.  The next generation of giant optical telescope currently in  the planning and study phase at the European Southern observatory  is the 100-m OWL. The current status of this project will be  discussed.

A new mechanism for relaxation of the cosmological constant through the production of membranes is presented. The membranes are produced by a thermal effect analogous to the process through which a particle can classically go over the top of a potential barrier due to a thermal excitation. After materialization the membranes collapse to form black holes. Thus the net effect is to transform the uniformly distributed vacuum energy into localized "matter" in the form of black holes. In the leading semiclassical approximation the process is governed by an unstable solution of the classical equations of motion whose Euclidean continuation - "thermalon" - is different from the previously studied instanton responsible for decay of the cosmological constant through tunneling.

I will present the main spectral and timing features of X-ray radiation that can be seen in black hole systems only. I will demonstrate that the photon-electron interaction along with general relativistic effects lead to the formation of a characteristic spectrum. Photon bending of the upscattered photons near a black hole horizon results in a powerful pair outflow that can be responsible for the jet formation near black holes.

I will describe different approaches in which string theory attempts to reproduce the structure of the Standard Model of Particle Physics, with an emphasis on recent constructions of brane world models (where the gauge sector is localized on a subspace of spacetime, while gravity propagates over all of spacetime) using D-branes.

Einstein's legacy is incomplete. His theory of General relativity raises -- but cannot answer -- three profound questions: What powered the Big Bang? What happens to space, time, and matter at the edge of a black hole? and, What is the mysterious dark energy pulling the Universe apart? The Beyond Einstein program within NASA's Office of Space Science aims to answer these questions, employing a series of missions linked by powerful new technologies and complementary approaches towards shared science goals. The Beyond Einstein program has three linked elements which advance science and technology towards two visions: to detect directly gravitational wave signals from the earliest possible moments of the Big Bang, and to image the event horizon of a black hole. The central element is a pair of Einstein Great Observatories, Constellation-X and LISA. Constellation-X is a powerful new X-ray observatory dedicated to X-ray spectroscopy. LISA is the first spaced based gravitational wave detector. These powerful facilities will blaze new paths to the questions about black holes, the Big Bang, and dark energy. The second element is a series of competitively selected Einstein probes, each focused on one of the science questions and includes a mission dedicated resolving the Dark Energy mystery. The third element is a program of technology development, theoretical studies, and education. The Beyond Einstein program is a new element in the proposed NASA budget for 2004. This talk will give an overview of the program and the missions contained within it.

I review modifications of the Hilbert action and of the canonical action obtained through careful treatment of the variations and of the quantities to be varied in obtaining the Einstein equations. One obtains from the canonical action equations of motion that define a Hamiltonian vector field that acts throughout the entire phase space, not just on the constraint hypersurface, as had been the case before these developments. The quasilocal energy is then obtained from the complete Hamiltonian with its boundary term. The exact equations of motion also imply, directly, causal conservation of the constraints through a first-order symmetric hyperbolic form of the third Bianchi identity. I describe in detail the final and complete form of the conformal method of solving the initial-value equations, both in Lagrangian and in Hamiltonian perspectives. (*) Several hyperbolic forms of the evolution equations are described. I consider various boundaries and boundary conditions. Important open problems for the vital area of numerical relativity include physically realistic, constraint-preserving boundary conditions and stricter bounds on the growth of the errors inherent in numerical work. The considerable progress made thus far has required mathematical work of a very high order. So will future progress.
(*) Harald Pfeiffer & James W. York, Phys. Rev. D 67: 044022 (2003)

Over the last couple of years the role of open string tachyons on the instability of D-branes has been well understood using the tools of string field theory and conformal field theory. After reviewing the key developments in this area we turn to the less understood time-dependent decay process of D-branes. We discuss the formation of tachyon matter and its possible interpretation as a non-relativistic gas of closed strings.