Features in the primordial spectrum: new constraints from WMAP7+ACT data
  and prospects for Planck
  We update the constraints on possible features in the primordial inflationary
density perturbation spectrum by using the latest data from the WMAP7 and ACT
Cosmic Microwave Background experiments. The inclusion of new data
significantly improves the constraints with respect to older work, especially
to smaller angular scales. While we found no clear statistical evidence in the
data for extensions to the simplest, featureless, inflationary model, models
with a step provide a significantly better fit than standard featureless
power-law spectra. We show that the possibility of a step in the inflationary
potential like the one preferred by current data will soon be tested by the
forthcoming temperature and polarization data from the Planck satellite
mission.
