14,817 research outputs found
R. Verrier, Etudes sur Arnaud de Villeneuve
No full textR. Verrier, Etudes sur Arnaud de Villeneuve. In: Revue d'histoire des sciences et de leurs applications, tome 3, n°2, 1950. pp. 193-194
Galaxy-cluster gas-density distributions of the representative XMM-Newton cluster structure survey (REXCESS)
No full textWe present a study of the structural and scaling properties of the gas distributions in the intracluster medium (ICM) of 31 nearby (z < 0.2) clusters observed with XMM-Newton, which together comprise the Representative XMM-Newton Cluster Structure Survey (REXCESS). In contrast to previous studies, this sample is unbiased with respect to X-ray surface brightness and cluster dynamical state, and it fully samples the cluster X-ray luminosity function. The clusters cover a temperature range of 2.0-8.5 keV and possess a variety of morphologies. The sampling strategy allows us to compare clusters with a wide range of central cooling times on an equal footing. We applied a recently developed technique for the deprojection and PSF-deconvolution of X-ray surface brightness profiles to obtain non-parametric gas-density profiles out to distances ranging between 0.8 R500 and 1.5 R500. We scaled the gas density distributions to allow for the systems' differing masses and redshifts. The central gas densities differ greatly from system to system, with no clear correlation with system temperature. At intermediate radii (~ 0.3 R500), the scaled density profiles show much less scatter, with a clear dependence on system temperature. We find that the density at this radius scales proportionally to the square root of temperature, consistent with the presence of an entropy excess as suggested in previous literature. However, at larger scaled radii this dependence becomes weaker: clusters with kT > 3 keV scale self-similarly, with no temperature dependence of gas-density normalisation. The REXCESS sample allows us to investigate the correlations between cluster properties and dynamical state. We find no evidence of correlations between cluster dynamical state and either the gas density slope in the inner regions or temperature, but do find some evidence of a correlation between dynamical state and outer gas density slope. We also find a weak correlation between dynamical state and both central gas normalisation and inner cooling times, but this is only significant at the 10% level. We conclude that, for the X-ray cluster population as a whole, both the central gas properties and the angle-averaged, large-scale gas properties are linked to the cluster dynamical state. We also investigate the central cooling times of the clusters. While the cooling times span a wide range, we find no evidence of a significant bimodality in the distributions of central density, density gradient, or cooling time. Finally, we present the gas mass-temperature relation for the REXCESS sample, finding that , which is consistent with the expectation of self-similar scaling modified by the presence of an entropy excess in the inner regions of the cluster and consistent with earlier work on relaxed cluster samples. We measure a logarithmic intrinsic scatter in this relation of ~, which should be a good measure of the intrinsic scatter in the -T relation for the cluster population as a whole
R. Verrier, Etudes sur Arnaud de Villeneuve
No full textR. Verrier, Etudes sur Arnaud de Villeneuve. In: Revue d'histoire des sciences et de leurs applications, tome 3, n°2, 1950. pp. 193-194
The universal galaxy cluster pressure profile from a representative sample of nearby systems (REXCESS) and the Y_SZ - M_500 relation
No full textWe investigate the regularity of cluster pressure profiles with REXCESS, a representative sample of 33 local (z < 0.2) clusters drawn from the REFLEX catalogue and observed with XMM-Newton. The sample spans a mass range of 1014 < M500 < 1015 , where M500 is the mass corresponding to a density contrast of 500. We derive an average profile from observations scaled by mass and redshift according to the standard self-similar model, and find that the dispersion about the mean is remarkably low, at less than 30 per cent beyond 0.2 R500, but increases towards the center. Deviations about the mean are related to both the mass and the thermo-dynamical state of the cluster. Morphologically disturbed systems have systematically shallower profiles while cooling core systems are more concentrated. The scaled profiles exhibit a residual mass dependence with a slope of ~0.12, consistent with that expected from the empirically-derived slope of the M500 – YX relation; however, the departure from standard scaling decreases with radius and is consistent with zero at R500. The scatter in the core and departure from self-similar mass scaling is smaller compared to that of the entropy profiles, showing that the pressure is the quantity least affected by dynamical history and non-gravitational physics. Comparison with scaled data from several state of the art numerical simulations shows good agreement outside the core. Combining the observational data in the radial range [0.03–1] R500 with simulation data in the radial range [1–4] R500, we derive a robust measure of the universal pressure profile, that, in an analytical form, defines the physical pressure profile of clusters as a function of mass and redshift up to the cluster “boundary”. Using this profile and direct spherical integration of the observed pressure profiles, we estimate the integrated Compton parameter Y and investigate its scaling with M500 and LX, the soft band X-ray luminosity. We consider both the spherically integrated quantity, Ysph(R), proportional to the gas thermal energy, and the cylindrically integrated quantity, Ycyl(R)=YSZ DA2, which is directly related to the Sunyaev-Zel'dovich (SZ) effect signal. From the low scatter of the observed Ysph(R500) – YX relation we show that variations in pressure profile shape do not introduce extra scatter into the Ysph(R500) – M500 relation as compared to that from the YX – M500 relation. The Ysph(R500) – M500 and Ysph(R500) – LX relations derived from the data are in excellent agreement with those expected from the universal profile. This profile is used to derive the expected YSZ – M500 and YSZ – LX relations for any aperture
Faire un stage de recherche à LAM. Entretien avec Arnaud Dupuy, stagiaire LAM
No full textFree consultation with a Doctor of mobile health team has Madagacar. Author : Docteur Ando. Licence : CC BY SA. https://commons.wikimedia.org/wiki/File:Free_consultation_with_a_Doctor_of_mobile_health_team_has_Madagacar.jpg En mai-juin 2019, Arnaud Dupuy a accompli un stage au laboratoire Les Afriques dans le monde, encadré par Jean-Philippe Berrou, enseignant-chercheur en économie. Il a été impliqué dans deux programmes de recherches pluridisciplinaires concernant l’aire africaine. Qu’est..
Polarization conversion in plasmonic nanoantennas for metasurfaces using structural asymmetry and mode hybridization
No full textData in support of the paper by Peter R. Wiecha, Leo-Jay Black, Yudong Wang, Vincent Paillard, Christian Girard, Otto L. Muskens & Arnaud Arbouet entitled "Polarization conversion in plasmonic nanoantennas for metasurfaces using structural asymmetry and mode hybridization" in Scientific Reports 7, Article number: 40906 (2017) doi:10.1038/srep40906</span
Response to Alexei Kassian’s review of The Indo-European elements in Hurrian
No full textFournet Arnaud. Response to Alexei Kassian’s review of The Indo-European elements in Hurrian [Электронный ресурс] / Fournet Arnaud, Bomhard Allan R.// Вопросы языкового родства. - 2011. - Вып. 5. - С. 135-141. - (Вестник РГГУ. Серия "Филологические науки. Языкознание" ; № 5 )
Response to Alexei Kassian’s review of The Indo-European elements in Hurrian
No full textFournet Arnaud. Response to Alexei Kassian’s review of The Indo-European elements in Hurrian [Электронный ресурс] / Fournet Arnaud, Bomhard Allan R.// Вопросы языкового родства. - 2011. - Вып. 5. - С. 135-141. - (Вестник РГГУ. Серия "Филологические науки. Языкознание" ; № 5 )
Dutch space; interview with Arnaud de Jong, CEO
No full textDutch Space, the largest space company in the Netherlands and part of Airbus Defence and Space, appointed a new CEO last year. The Leonardo Times sat down with the CEO Arnaud de Jong for an interview. We discuss his career, developments in Dutch Space, his take on competition in the commercial space domain and his future outlook on European and International space markets.Aerospace Engineerin
Dataset for Quantum Theory of Near-field Optical Imaging with Rare-earth Atomic Clusters
No full textDataset supports the paper: Clément Majorel, Christian Girard, Aurélien Cuche, Arnaud Arbouet, and Peter R. Wiecha "Quantum Theory of Near-field Optical Imaging with Rare-earth Atomic Clusters". JOSA B 37(5), 1474-1484 (2020)</span
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