wewanttofindthecosmologicalconstantinfluenceoncosmicmicrowavebackground(cmb)temperatureduetomovinglinearcosmicstrings.usingthespace-timemetricofalinearcosmicstringinanacceleratedexpandinguniverse,thegott-kaiser stebbins(gks)effect,asanimportantmechanisminproducingtemperaturediscontinuityinthe(cmb),isconsidered;then,itsmodificationduetotheeffectofthecosmologicalconstantiscalculated.theresultshowsthat...

Wewanttofindthecosmologicalconstantinfluenceoncosmicmicrowavebackground(CMB)temperatureduetomovinglinearcosmicstrings.Usingthespace-timemetricofalinearcosmicstringinanacceleratedexpandinguniverse,theGott-Kaiser Stebbins(GKS)effect,asanimportantmechanisminproducingtemperaturediscontinuityinthe(CMB),isconsidered;then,itsmodificationduetotheeffectofthecosmologicalconstantiscalculated.Theresultshowsthat...

cosmic rays (cr) travel at speeds essentially indistinguishable from the speed of light. however whilst travelling through magnetic fields, both regular and turbulent, they are delayed behind the light since they are usually charged particles and their paths are not linear. those delays can be so long that they are an impediment to correctly identifying sources which may be variable in time. fu...

In these lectures, I review the current status of cosmic strings and cosmic superstrings. I first discuss topological defects in the context of Grand Unified Theories, focusing in particular in cosmic strings arising as gauge theory solitons. I discuss the reconciliation between cosmic strings and cosmological inflation, I review cosmic strings dynamics, cosmic string thermodynamics and cosmic ...

Recent developments in string theory suggest that cosmic strings could be formed at the end of brane inflation. Supergravity provides a realistic model to study the properties of strings arising in brane inflation. Whilst the properties of cosmic strings in flat space-time have been extensively studied there are significant complications in the presence of gravity. We study the effects of gravi...

Recent developments in string theory suggest that cosmic strings could be formed at the end of brane inflation. Supergravity provides a realistic model to study the properties of strings arising in brane inflation. Whilst the properties of cosmic strings in flat space-time have been extensively studied there are significant complications in the presence of gravity. We study the effects of gravi...

Spatially homogeneous Bianchi type-II, VIII and IX anisotropic, as well as isotropic cosmological models can be obtained in a scalar tensor theory of gravitation proposed by Saez and Ballester (1986) when the source for energy momentum tensor is a bulk viscous fluid containing one-dimensional cosmic strings. All the models obtained and presented here are expanding, non-rotating and accelerating...