Collège de France

About: Collège de France is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Receptor. The organization has 6541 authors who have published 11983 publications receiving 648742 citations. The organization is also known as: College de France.

Parameter estimation for compact binary coalescence signals with the first generation gravitational-wave detector network

Abstract: Compact binary systems with neutron stars or black holes are one of the most promising sources for ground-based gravitational-wave detectors. Gravitational radiation encodes rich information about source physics; thus parameter estimation and model selection are crucial analysis steps for any detection candidate events. Detailed models of the anticipated waveforms enable inference on several parameters, such as component masses, spins, sky location and distance, that are essential for new astrophysical studies of these sources. However, accurate measurements of these parameters and discrimination of models describing the underlying physics are complicated by artifacts in the data, uncertainties in the waveform models and in the calibration of the detectors. Here we report such measurements on a selection of simulated signals added either in hardware or software to the data collected by the two LIGO instruments and the Virgo detector during their most recent joint science run, including a "blind injection'' where the signal was not initially revealed to the collaboration. We exemplify the ability to extract information about the source physics on signals that cover the neutron-star and black-hole binary parameter space over the component mass range 1M(circle dot)-25M(circle dot) and the full range of spin parameters. The cases reported in this study provide a snapshot of the status of parameter estimation in preparation for the operation of advanced detectors.

Existence and role of the precursor film in the spreading of polymer liquids.

Abstract: We present investigations of the spreading behavior of nonvolatile liquids (high-molecular-weight polydimethylsiloxane) on smooth horizontal surfaces, and establish the following: (1) the existence of a thin precursor film extending progressively ahead of the macroscopic front of the drops, and that we directly visualize by polarized reflection microscopy; (2) the universality of the spreading kinetics, followed by means of simultaneous size and contact-angle measurements, which appears insensitive to the spreading parameter $S$. Both points give strong experimental support to recent theoretical developments.