جستجوی مقالات مرتبط با کلیدواژه « همگرایی گرانشی » در نشریات گروه « فیزیک »

The cold spot is one of the observed CMB anomalies proposed to be produced by various primary and secondary effects. In this work, we study the gravitational lensing of some of the candidates that could produce the cold spot, namely a huge void and a cosmic texture, on the various components of CMB random field. Our results demonstrated that the signal to noise ratio of gravitational lensing effect on the CMB temperature field is higher than that of on CMB polarization. We found that for a cylindrically symmetric void at z_Void=0.8 with σ=-1.0   a thousand minute observation would detect the gravitational lensing signal while for a cosmic texture at z_Texture=6.0 a longer observation is required. We expect the future high resolution surveys can put strong constraints on the amplitudes of the template of these models.

In this paper, we study a restricted modified gravity in which diffeomorphism symmetry is broken. We investigate the astrophysical implications of the model by using the corresponding gravitational potential. By using the weight function of the weak lensing , for the model, the deviation of the model with respect to  model has been studied for the late-time cosmology.

In this paper a model with anisotropic pressures for dark matter halo is assumed. The corresponding metric matches the schwarzchild metric at the surface of halo. Then the energy conditions, rotation curve and gravitational lensing effect are investigated.