Search results for "Gravitational lensing formalism"
showing 4 items of 4 documents
Gravitational lensing on the Cosmic Microwave Background by gravity waves
1997
We study the effect of a stochastic background of gravitational waves on the gravitational lensing of the Cosmic Microwave Background (CMB) radiation. It has been shown that matter density inhomogeneities produce a smoothing of the acoustic peaks in the angular power spectrum of the CMB anisotropies. A gravitational wave background gives rise to an additional smoothing of the spectrum. For the most simple case of a gravitational wave background arising during a period of inflation, the effect results to be three to four orders of magnitude smaller than its scalar counterpart, and is thus undetectable. It could play a more relevant role in models where a larger background of gravitational wa…
Weak Lensing Observables in the Halo Model
2011
The halo model (HM) describes the inhomogeneous universe as a collection of halos. The full nonlinear power spectrum of the universe is well approximated by the HM, whose prediction can be easily computed without lengthy numerical simulations. This makes the HM a useful tool in cosmology. Here we explore the lensing properties of the HM by use of the stochastic gravitational lensing (sGL) method. We obtain for the case of point sources exact and simple integral expressions for the expected value and variance of the lensing convergence, which encode detailed information about the internal halo properties. In particular a wide array of observational biases can be easily incorporated and the d…
Accurate modeling of weak lensing with the stochastic gravitational lensing method
2011
We revise and extend the stochastic gravitational lensing method (the sGL method) first introduced by Kainulainen and Marra [Phys. Rev. D 80, 123020 (2009)]. Here we include a realistic halo-mass function and density profiles to model the distribution of mass between and within galaxies, galaxy groups, and galaxy clusters. We also introduce a modeling of the filamentary large-scale structures and a method to embed halos into these structures. We show that the sGL method naturally reproduces the weak lensing results for the Millennium simulation. The strength of the sGL method is that a numerical code based on it can compute the lensing probability distribution function (PDF) for a given inh…
Integral field spectroscopy of the gravitational lens HE1104-1805
2004
We present integral field spectroscopy of the double imaged quasar HE1104-1805 taken with the optical fiber system INTEGRAL-WYFFOS at theWHT telescope. From the spectra of the two components we have measured the continuum and line emission ratios, finding an offset between them that can be related to microlensing. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)