Astrophysics
Dark energy might have an influence on the formation of non--linear structures during the cosmic history. For example, in models in which dark energy couples to dark matter, it will be non--homogeneous and will influence the collapse of a…
Until the advent of XMM-Newton, the cluster soft excess (CSE) was the subject of some controversy due to both data analysis issues and uncertainties with the soft excess emission mechanism. XMM-Newton observations have finally laid to rest…
The project of a micro-TPC matrix of cells of 3He for direct detection of non-baryonic dark matter is presented. The privileged properties of 3He for this detection are highlighted. The double detection: ionization-projection of tracks is…
This paper presents a brief review of the evidence for dark matter in the Universe on the scales of galaxies. In the interests of critically and objectively testing the dark matter paradigm on these scales, this evidence is weighed against…
The WARP programme for dark matter search with a double phase argon detector is presented. In such a detector both excitation and ionization produced by an impinging particle are evaluated by the contemporary measurement of primary…
The dark matter problem will be solved only when all of the dark matter is accounted for. Although wimps may be discovered in direct detection experiments soon, we will not know what fraction of the dark matter halo they compose until we…
We present first competitive results on WIMP dark matter using the phonon-light-detection technique. A particularly strong limit for WIMPs with coherent scattering results from selecting a region of the phonon-light plane corresponding to…
This article reviews the life and death of a scientific theory.
We have carried out the dark matter search with a 116g direction-sensitive stilbene crystal in Kamioka Observatory. With the crystal fixed to the earth, we searched the modulation of thelight output. No modulation signal was found due to…
Microlensed double-image quasars have sent a consistent message that the baryonic dark matter consists of a population of free-roaming planet mass objects, as summarized previously. These were previously predicted to have formed at the time…
We review observational evidence and open issues related to the process of magnetospheric accretion in T Tauri stars. Emphasis is put on recent numerical simulations and observational results which suggest that the interaction between the…
Observations of young stellar objects, such as classical T Tauri stars (CTTSs), show evidence of accretion disks (ADs), outflows and jets. It is shown that Alfven waves (AWs) are important in all of these phenomena. AWs can be created by…
The scientific goal of the SACY (Search for Associations Containing Young-stars) was to identify possible associations of stars younger than the Pleiades Association among optical counterparts of the ROSAT X-ray bright sources.…
We use our Monte Carlo radiative transfer code to study non-embedded prestellar cores and cores that are embedded at the centre of a molecular cloud. Our study indicates that the temperature inside embedded cores is lower than in isolated…
We present Halpha spectropolarimetry of a large sample of pre-main sequence (PMS) stars of low and intermediate mass, and argue that the technique is a powerful tool in studying the circumstellar geometry around these objects. For the…
The sigma Orionis cluster is a young association evolving under the disruptive influence of its massive O-star namesake. We are analysing this cluster as part of a program to characterise the influence of O-stars on the early stages of…
I discuss results from the recent spectroscopic survey for solar-type pre-MS stars in the Lower Centaurus-Crux (LCC) and Upper Centaurus-Lupus (UCL) OB subgroups by Mamajek, Meyer, & Liebert (2002, AJ, 124, 1670). LCC and UCL are subgroups…
Using the Chandra ACIS-I instruments, we have carried out the deepest X-ray observation on a typical Galactic plane region at l 28.5 deg, where no discrete X-ray sources have been known previously. We have detected, as well as strong…
Among a number of gamma-ray bursts whose host galaxies are known, GRB971214 stands out for its high redshift(z=3.25) and the Lya emission line having a P-Cygni type profile. which is interpreted to be a direct consequence of the expanding…
Continuum and emission-line variability of active galactic nuclei provides a powerful probe of microarcsecond scale structures in the central regions of these sources. In this contribution, we review basic concepts and methodologies used in…