Characterizing SL2S galaxy groups using the Einstein radius

We analyzed the Einstein radius, $\theta_E$, in our sample of SL2S galaxy groups, and compared it with $R_A$ (the distance from the arcs to the center of the lens), using three different approaches: 1.- the velocity dispersion obtained from weak lensing assuming a Singular Isothermal Sphere profile ($\theta_{E,I}$), 2.- a strong lensing analytical method ($\theta_{E,II}$) combined with a velocity dispersion-concentration relation derived from numerical simulations designed to mimic our group sample, 3.- strong lensing modeling ($\theta_{E,III}$) of eleven groups (with four new models presented in this work) using HST and CFHT images. Finally, $R_A$ was analyzed as a function of redshift $z$ to investigate possible correlations with L, N, and the richness-to-luminosity ratio (N/L). We found a correlation between $\theta_{E}$ and $R_A$, but with large scatter. We estimate $\theta_{E,I}$ = (2.2 $\pm$ 0.9) + (0.7 $\pm$ 0.2)$R_A$, $\theta_{E,II}$ = (0.4 $\pm$ 1.5) + (1.1 $\pm$ 0.4)$R_A$, and $\theta_{E,III}$ = (0.4 $\pm$ 1.5) + (0.9 $\pm$ 0.3)$R_A$ for each method respectively. We found a weak evidence of anti-correlation between $R_A$ and $z$, with Log$R_A$ = (0.58$\pm$0.06) - (0.04$\pm$0.1)$z$, suggesting a possible evolution of the Einstein radius with $z$, as reported previously by other authors. Our results also show that $R_A$ is correlated with L and N (more luminous and richer groups have greater $R_A$), and a possible correlation between $R_A$ and the N/L ratio. Our analysis indicates that $R_A$ is correlated with $\theta_E$ in our sample, making $R_A$ useful to characterize properties like L and N (and possible N/L) in galaxy groups. Additionally, we present evidence suggesting that the Einstein radius evolves with $z$.Comment: Accepted for publication in Astronomy & Astrophysics. Typos correcte

Surface acoustic wave investigations of the metal-to-insulator transition of V2O3 thin films on lithium niobate

Thin V2O3 films were deposited on a piezoelectric substrate by electron-beam evaporation. Surface acoustic waves (SAW) were generated by interdigital-transducers (IDTs). The attenuation and sound velocity was investigated from 260K to 10K, providing an insight into the temperature dependent electrical, dielectrical and elastic properties of V2O3 at the metal to insulator transition.Comment: 7 pages, 7 figure

The dark matter distribution in z~0.5 clusters of galaxies. I : Determining scaling relations with weak lensing masses

The total mass of clusters of galaxies is a key parameter to study massive halos. It relates to numerous gravitational and baryonic processes at play in the framework of large scale structure formation, thus rendering its determination important but challenging. From a sample of the 11 X-ray bright clusters selected from the excpres sample, we investigate the optical and X-ray properties of clusters with respect to their total mass derived from weak gravitational lensing. From multi-color wide field imaging obtained with MegaCam at CFHT, we derive the shear profile of each individual cluster of galaxies. We perform a careful investigation of all systematic sources related to the weak lensing mass determination. The weak lensing masses are then compared to the X-ray masses obtained from the analysis of XMM observations and assuming hydrostatic equilibrium. We find a good agreement between the two mass proxies although a few outliers with either perturbed morphology or poor quality data prevent to derive robust mass estimates. The weak lensing mass is also correlated with the optical richness and the total optical luminosity, as well as with the X-ray luminosity, to provide scaling relations within the redshift range 0.4<z<0.6. These relations are in good agreement with previous works at lower redshifts. For the L_X-M relation we combine our sample with two other cluster and group samples from the literature, thus covering two decades in mass and X-ray luminosity, with a regular and coherent correlation between the two physical quantities

Le Cancer des Plantes ou Crown-Gall.

Foëx E. Le Cancer des Plantes ou Crown-Gall.. In: Revue de botanique appliquée et d'agriculture coloniale, 5ᵉ année, bulletin n°42, 28 février 1925. pp. 97-105

Quelques problèmes relatifs aux Rouilles des Céréales.

Foex . Quelques problèmes relatifs aux Rouilles des Céréales.. In: Revue de botanique appliquée et d'agriculture coloniale, 3ᵉ année, bulletin n°26, octobre 1923. pp. 641-652

Histoire de l'introduction de quelques nouvelles Maladies des plantes.

Foëx E. Histoire de l'introduction de quelques nouvelles Maladies des plantes. In: Revue de botanique appliquée et d'agriculture coloniale, 4ᵉ année, bulletin n°37, septembre 1924. pp. 561-568

Note sur les maladies de la dégénérescence de la Pomme de terre

Ducomet , Foex . Note sur les maladies de la dégénérescence de la Pomme de terre. In: Revue de botanique appliquée et d'agriculture coloniale, 2ᵉ année, bulletin n°11, 31 juillet 1922. pp. 325-330

La Conférence de Pathologie végétale de Hollande. (Juin 1923).

Ducomet V., Foëx E. La Conférence de Pathologie végétale de Hollande. (Juin 1923).. In: Revue de botanique appliquée et d'agriculture coloniale, 4ᵉ année, bulletin n°33, 31 mai 1924. pp. 305-316

Une maladie du Bananier.

Foëx E., Lansade M. Une maladie du Bananier. In: Revue de botanique appliquée et d'agriculture coloniale, 16ᵉ année, bulletin n°183, novembre 1936. pp. 887-892