Séminaire / Seminar GReCO |
| « Punctuated inflation and the low CMB multipoles » |
|
L. Sriramkumar |
| We investigate inflationary scenarios driven by a class of potentials that are similar in form to those that arise in certain minimal supersymmetric extensions of the standard model. We find that these potentials allow a brief period of rapid roll sandwiched between two stages of slow roll inflation, a scenario which we refer to as punctuated inflation. We show that such a background behavior leads to a step like feature in the scalar power spectrum. We set the scales such that the drop in the power spectrum occurs at a length scale that corresponds to the Hubble radius today---a feature that seems necessary to explain the lower power observed in the quadrupole moment of the Cosmic Microwave Background (CMB) anisotropies. We perform a Markov Chain Monte Carlo analysis to determine the values of the model parameters that provide the best fit to the recent WMAP 5-year data for the CMB angular power spectrum. We find that an inflationary spectrum with a suppression of power at large scales that we obtain leads to a better fit of the observed data when compared to the best fit reference \LambdaCDM model with a featureless, power law, primordial spectrum. We also discuss the effects of punctuated inflation on the tensor power spectrum. |
|
lundi 19 octobre 2009 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |