Optimal limits on f_{NL}^{local} from WMAP 5-year data

Understand

We have applied the optimal estimator for f_{NL}^{local} to the 5 year WMAP data.

• Marginalizing over the amplitude of foreground templates we get -4 < f_{NL}^{local} < 80 at 95% CL.
• Error bars of previous (sub-optimal) analyses are roughly 40% larger than these.
• The probability that a Gaussian simulation, analyzed using our estimator, gives a result larger in magnitude than the one we find is 7%.