Résumé / Abstract Seminaire_IAP
« Exploring the halo of galaxies with the SDSS »

Brice Menard
Canadian Inst. Theor. Astroph. (CITA), Univ. Toronto (Toronto, Canada)

I will present a simultaneous detection of gravitational magnification and dust reddening effects due to galactic halos and large-scale structure. The measurement is based on correlating the brightness of 100,000 quasars at z>1 with the position of 20 million foreground galaxies derived from the SDSS.

(i) From magnification measurements we constrain the galaxy-mass correlation up to 20 Mpc scales and compare the results with estimates from gravitational shear. (ii) From reddening measurements we constrain the galaxy-dust correlation from 20 kpc to several Mpc, providing the first constraints on the amount of dust in galactic halos and beyond. I will present the spatial distribution and wavelength dependence of this diffuse dust component. I will then estimate of the opacity of the Universe, the cosmic density of dust and the implications for supernova experiments.
vendredi 9 janvier 2009 - 11:00
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
Page web du séminaire / Seminar's webpage