BOOMERanG constraints on primordial non-Gaussianity from analytical Minkowski functionals

We use Minkowski functionals (MFs) to constrain a primordial non-Gaussian contribution to the cosmic microwave background intensity field as observed in the 150- and 145-GHz BOOMERanG maps from the 1998 and 2003 flights, respectively, performing for the first time a joint analysis of the two data sets. A perturbative expansion of the MF formulae in the limit of a weakly non-Gaussian field yields analytical formulae, derived by Hikage et al., which can be used to constrain the coupling parameter f<SUB>NL</SUB> without the need for non-Gaussian simulations. We find -770 < f<SUB>NL</SUB> < 500 at 95 per cent CL, significantly improving the previous constraints by De Troia et al. on the BOOMERanG 2003 data set. These are the best f<SUB>NL</SUB> limits to date for suborbital probes.