Sökresultat

We present an experimental study of velocity fluctuations in quasistatic flow of a 2D granular material deformed in a shear apparatus named 1γ2ε [1]. Radjaï and Roux [2] revealed systematic similarities between velocity fluctuations observed in discrete element simulations of quasistatic flow of granular material and turbulent flows in fluids. The character of these velocity fluctuations - named g

One of the common tools for studying the deformation behavior of the microstructure in polycrystalline materials is crystal plasticity models. These are used to describe texture evolution and hardening due to crystallographic slip. A drawback when using crystal plasticity models is that the calculation of the slip requires solving a set of stiff differential equations for each grain in the microst

Context. The Milky Way nuclear star cluster (MWNSC) is located in the Galactic centre, together with the Milky Way nuclear stellar disc (MWNSD), and they dominate the gravitational potential within the inner 300 pc. However, the formation and evolution of the two systems and their possible connections are still under debate. Aims. We reanalysed the low-resolution KMOS spectra in the MWNSC with the

We introduce MEGATRON, a new galaxy formation model for cosmological radiation hydrodynamics simulations of high-redshift galaxies. The model accounts for the non-equilibrium chemistry and heating/cooling processes of ≥ 80 atoms, ions, and molecules, coupled to on-the-fly radiation transfer. We apply the model in a cosmological setting to the formation of a 109 M⊙halo at z = 6, and run 25 realizat

Determining the prevalence of atmospheres on terrestrial planets is a core objective in exoplanetary science. While M dwarf systems offer a promising opportunity, conclusive observations of terrestrial atmospheres have remained elusive, with many yielding flat transmission spectra. We observe four transits of the hot terrestrial planet TOI-1685 b using James Webb Space Telescope (JWST)’s Near Infr

Cetaceans are negatively affected by anthropogenic activities, including acoustic and physical disturbance from boat traffic. Behavioural responses to such disturbances are context-dependent, and site-specific insights are needed for effective local management plans. In this study, the impact of speed and proximity of recreational boats on the swimming speed and surfacing interval of one of the mo

Context. The Near-InfraRed Planet Searcher (NIRPS) is a high-resolution, high-stability near-infrared (NIR) spectrograph equipped with an adaptive optics (AO) system. Installed on the ESO 3.6-m telescope at La Silla Observatory, Chile, it was developed to enable radial velocity (RV) measurements of low-mass exoplanets around M dwarfs and to characterise exoplanet atmospheres in the NIR. Aims. This

We obtained 420 high-resolution spectra of Proxima, over 159 nights, using the Near Infra Red Planet Searcher (NIRPS). We derived 149 nightly binned radial velocity measurements with a standard deviation of 1.69 m s−1 and a median uncertainty of 55 cm s−1, and performed a joint analysis combining radial velocities, spectroscopic activity indicators, and ground-based photometry, to model the planet

Context. Near-infrared high-resolution échelle spectrographs unlock access to fundamental properties of exoplanets, from their atmospheric escape and composition to their orbital architecture, which can all be studied simultaneously from transit observations. Aims. We present the first results of the newly commissioned ESO near-infrared spectrograph, Near-InfraRed Planet Searcher (NIRPS), from thr

Hirshfeld atom refinement (HAR) provides a more realistic interpretation of crystallographic data than the standard independent atom model (IAM) by using aspherical atomic form factors derived from quantum mechanical (QM) calculations. With this aspherical description, it is possible to obtain improved atomic positions, atomic displacement parameters and correct bond lengths even for hydrogen atom