Search Publications
An operational software tool for the analysis of coronagraph images: Determining CME parameters for input into the WSA-Enlil heliospheric model
de Koning, C. A.; Pizzo, V.; Millward, G. +1 more
Coronal mass ejections (CMEs)—massive explosions of dense plasma that originate in the lower solar atmosphere and propagate outward into the solar wind—are the leading cause of significant space weather effects within Earth's environment. Computational models of the heliosphere such as WSA-Enlil offer the possibility of predicting whether a given …
Improving the Precision of Time-delay Cosmography with Observations of Galaxies along the Line of Sight
Treu, Tommaso; Bradač, Maruša; Marshall, Philip J. +8 more
In order to use strong gravitational lens time delays to measure precise and accurate cosmological parameters the effects of mass along the line of sight must be taken into account. We present a method to achieve this by constraining the probability distribution function of the effective line-of-sight convergence κext. The method is bas…
Vlasov Simulations of Multi-ion Plasma Turbulence in the Solar Wind
Veltri, P.; Perrone, D.; Servidio, S. +2 more
Hybrid Vlasov-Maxwell simulations are employed to investigate the role of kinetic effects in a two-dimensional turbulent multi-ion plasma, composed of protons, alpha particles, and fluid electrons. In the typical conditions of the solar-wind environment, and in situations of decaying turbulence, the numerical results show that the velocity distrib…
On the Origin of Mass Segregation in NGC 3603
Grebel, Eva K.; Drissen, Laurent; Moffat, Anthony F. J. +5 more
We present deep Hubble Space Telescope/Wide Field and Planetary Camera 2 photometry of the young HD 97950 star cluster in the giant H II region NGC 3603. The data were obtained in 1997 and 2007 permitting us to derive membership based on proper motions of the stars. Our data are consistent with an age of 1 Myr for the HD 97950 cluster. A possible …
Molecular gas in the centre of nearby galaxies from VLT/SINFONI integral field spectroscopy - I. Morphology and mass inventory
Saglia, R. P.; Nowak, N.; Thomas, J. +7 more
We present the first results of an analysis of the properties of the molecular gas in the nuclear regions (r ≲ 300 pc) of a sample of six nearby galaxies, based on new high-spatial-resolution observations obtained in the K-band with the near-infrared integral field spectrograph SINFONI at the Very Large Telescope. We derive 2D distributions of the…
A new diffusion matrix for whistler mode chorus waves
Meredith, Nigel P.; Horne, Richard B.; Glauert, Sarah A. +5 more
Global models of the Van Allen radiation belts usually include resonant wave-particle interactions as a diffusion process, but there is a large uncertainty over the diffusion rates. Here we present a new diffusion matrix for whistler mode chorus waves that can be used in such models. Data from seven satellites are used to construct 3536 power spec…
Discovery of a New Kind of Explosive X-Ray Transient near M86
Maccarone, T.; Fender, R.; Miller-Jones, J. C. A. +6 more
We present the discovery of a new type of explosive X-ray flash in Chandra images of the old elliptical galaxy M86. This unique event is characterized by the peak luminosity of 6 × 1042 erg s-1 for the distance of M86, the presence of precursor events, the timescale between the precursors and the main event (~4000 s), the abs…
Reflectance spectra diversity of silica-rich materials: Sensitivity to environment and implications for detections on Mars
Bell, J. F.; Rice, M. S.; Horgan, B. H. +7 more
Hydrated silica-rich materials have recently been discovered on the surface of Mars by the Mars Exploration Rover (MER) Spirit, the Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), and the Mars Express Observatoire pour la Minéralogie, l’Eau, les Glaces, et l’Activité (OMEGA) in several locations. Hav…
One Moon, Many Measurements 3: Spectral reflectance
Yokota, Y.; Mall, U.; Besse, S. +9 more
Remote-sensing datasets obtained by each instrument aboard Selenological and Engineering Explorer (SELENE) and Chandrayaan-1 have not been compared directly, and the characteristics of each instrument’s data, which may reflect the observation conditions of each instrument and/or residual error in instrument calibration, are unknown. This paper des…
Ca II H+K fluxes from S-indices of large samples: a reliable and consistent conversion based on PHOENIX model atmospheres
Schmitt, J. H. M. M.; Schröder, K. -P.; Mittag, M.
Context. Historic stellar activity data based on chromospheric line emission using O.C. Wilson's S-index reach back to the 1960ies and represent a very valuable data resource both in terms of quantity and time-coverage. However, these data are not flux-calibrated and are therefore difficult to compare with modern spectroscopy and to relate to quan…