Search Publications
Information gains from cosmological probes
Amara, A.; Refregier, A.; Grandis, S. +2 more
In light of the growing number of cosmological observations, it is important to develop versatile tools to quantify the constraining power and consistency of cosmological probes. Originally motivated from information theory, we use the relative entropy to compute the information gained by Bayesian updates in units of bits. This measure quantifies …
The binary populations of eight globular clusters in the outer halo of the Milky Way
Milone, A. P.; Marino, A. F.; Bedin, L. R. +6 more
We analyse colour-magnitude diagrams of eight globular clusters (GCs) in the outer Galactic halo. Images were taken with the Wide Field Channel of the Advanced Camera for Survey and the Ultraviolet and Visual Channel of the Wide Field Camera 3 on board of the Hubble Space Telescope. We have determined the fraction of binary stars along the main se…
Constraining multiplicative bias in CFHTLenS weak lensing shear data
Hill, J. Colin; Liu, Jia; Ortiz-Vazquez, Alvaro
Several recent cosmological analyses have found tension between constraints derived from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) data and those derived from other data sets, such as the Planck cosmic microwave background (CMB) temperature anisotropies. Similarly, a direct cross-correlation of the CFHTLenS data with Planck CMB …
Tether-cutting Reconnection between Two Solar Filaments Triggering Outflows and a Coronal Mass Ejection
Zhang, Jun; Li, Leping; Chen, Huadong +1 more
Triggering mechanisms of solar eruptions have long been a challenge. A few previous case studies have indicated that preceding gentle filament merging via magnetic reconnection may launch following intense eruption, according to the tether-cutting (TC) model. However, the detailed process of TC reconnection between filaments has not been exhibited…
Ion Dynamics at a Rippled Quasi-parallel Shock: 2D Hybrid Simulations
Wang, Shui; Hao, Yufei; Lu, Quanming +1 more
In this paper, two-dimensional hybrid simulations are performed to investigate ion dynamics at a rippled quasi-parallel shock. The results show that the ripples around the shock front are inherent structures of a quasi-parallel shock, and the re-formation of the shock is not synchronous along the surface of the shock front. By following the trajec…
The Distribution of Mass Surface Densities in a High-mass Protocluster
Kainulainen, Jouni; Tan, Jonathan C.; Lim, Wanggi +2 more
We study the probability distribution function (PDF) of mass surface densities, Σ, of infrared dark cloud (IRDC) G028.37+00.07 and its surrounding giant molecular cloud. This PDF constrains the physical processes, such as turbulence, magnetic fields, and self-gravity, that are expected to be controlling cloud structure and star formation activity.…
Galactic cold cores. VII. Filament formation and evolution: Methods and observational constraints
Bernard, J. -P.; Juvela, M.; Marshall, D. J. +15 more
Context. The association of filaments with protostellar objects has made these structures a priority target in star formation studies. However, little is known about the link between filament properties and their local environment.
Aims: The datasets from the Herschel Galactic Cold cores key programme allow for a statistical study of filament…
Acceleration of cometary dust near the nucleus: application to 67P/Churyumov-Gerasimenko
Hartogh, Paul; Skorov, Yuri; Reshetnyk, Volodymyr +2 more
We present a model of cometary dust capable of simulating the dynamics within the first few tens of km of the comet surface. Recent measurements by the Grain Impact Analyser and Dust Accumulator and Cometary Secondary Ion Mass Analyser instruments on Rosetta show that the nucleus emits fluffy dust particles with porosities above 50 per cent and si…
Solving 3D relativistic hydrodynamical problems with weighted essentially nonoscillatory discontinuous Galerkin methods
Dietrich, Tim; Bugner, Marcus; Bernuzzi, Sebastiano +2 more
Discontinuous Galerkin (DG) methods coupled to weighted essentially nonoscillatory (WENO) algorithms allow high order convergence for smooth problems and for the simulation of discontinuities and shocks. In this work, we investigate WENO-DG algorithms in the context of numerical general relativity, in particular for general relativistic hydrodynam…
Observations of Oppositely Directed Umbral Wavefronts Rotating in Sunspots Obtained from the New Solar Telescope of BBSO
Chen, J.; Banerjee, D.; Su, J. T. +7 more
We study the umbral waves as observed by chromospheric imaging observations of two sunspots with the New Solar Telescope at the Big Bear Solar Observatory. We find that the wavefronts (WFs) rotate clockwise and form a one-armed spiral structure in the first sunspot, whereas two- and three-armed structures arise in the second sunspot where the WFs …