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We first compare the CMB lensing model of Seljak (1996) with the empirical model of Lieu & Mittaz (2005) to determine if the latter approach implies a larger effect on the CMB power-spectrum. We find that the empirical model gives significantly higher results for the magnification dispersion, assuming standard cosmological parameters. However, when the empirical foreground model is modelled via correlation functions and used in the Seljak formalism, the agreement is considerably improved. Thus we conclude that the main difference may be in the assumed foregrounds. We then discuss a foreground mass distribution which gives a lensing dispersion which is constant with angle. In Seljaks formalism, we show this can lead to a smoothing of the CMB power-spectrum which may be able to move the first acoustic peak to smaller l, if the mass clustering amplitude is high enough. Evidence for such a high amplitude comes from the QSO magnification results of Myers et al (2003, 2005) who suggest that foreground galaxy groups may be more massive than expected, implying that Omega_m ~ 1 and strong galaxy anti-bias. We then show that an inflationary model with neither CDM nor a cosmological constant and that predicts a primordial first peak at l=330 may fit the first acoustic peak of the WMAP data. This fit may be regarded as somewhat contrived since it also requires high redshift reionisation at the upper limit of what is allowed by the WMAP results. But given the finely-tuned nature of the standard LCDM model, the contrivance may be small in comparison and certainly the effect of lensing and other foregrounds may still have a considerable influence on the cosmological interpretation of the CMB.
We simulate the anisotropy in the cosmic microwave background (CMB) induced by cosmic strings. By numerically evolving a network of cosmic strings we generate full-sky CMB temperature anisotropy maps. Based on $192$ maps, we compute the anisotropy po
We provide a detailed treatment and comparison of the weak lensing effects due to large-scale structure (LSS), or scalar density perturbations and those due to gravitational waves(GW) or tensor perturbations, on the temperature and polarization power
Magnetic fields are everywhere in nature and they play an important role in every astronomical environment which involves the formation of plasma and currents. It is natural therefore to suppose that magnetic fields could be present in the turbulent
In the present work, we study the largest structures of the CMB temperature measured by Planck in terms of the most prominent peaks on the sky, which, in particular, are located in the southern galactic hemisphere. Besides these large-scale features,
We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than $60^circ$, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimut