The halo squeezed-limit bispectrum with primordial non-Gaussianity: a power spectrum response approach

摘要

Modeling the nonlinearity of the halo bispectrum remains a major challenge inmodern cosmology, in particular for ongoing and upcoming large-scale structureobservations that are performed to study the inflationary physics. The "powerspectrum response" offers a solution for bispectrum in the so-called squeezedlimit, in which one wavenumber is much smaller than the other two. As a firststep, we demonstrate that the halo squeezed-limit bispectrum computed from thesecond-order standard perturbation theory agrees precisely with the responsesof linear halo power spectrum to large-scale density and potentialfluctuations. Since the halo power spectrum responses to arbitrarily smallscales can straightforwardly be obtained by separate universe simulations, theresponse approach provides a novel and powerful technique for modeling thenonlinear halo squeezed-limit bispectrum.