The Halo Bispectrum Multipoles in Redshift Space
  We present the analysis of the halo bispectrum in redshift-space in terms of
its multipoles, monopole, quadrupole and hexadecapole, measured from a large
set of simulations. We fit such measurements with a tree-level model in
perturbation theory that depends on linear and nonlinear bias parameters as
well as on the growth rate $f$ of density fluctuations. The likelihood analysis
takes advantage of a very large set of mock catalogs, enabling a robust
estimation of the covariance properties for all multipoles. We compare the
numerical estimate of the covariance matrix to its Gaussian prediction finding
discrepancies of 10% or less for all configurations with the sole exception of
the squeezed triangles in the monopole case. We find the range of validity of
the tree-level model, for the total simulation volume of about 1000 $h^{-3}\,
{\rm Gpc}^3$, reaches a maximum wavenumber of $0.08 \, h \, {\rm Mpc}^{-1}$ for
the monopole, while it is limited to $0.06$ and $0.045\, h \, \rm{Mpc}^{-1}$
respectively for quadrupole and hexadecapole. Despite this, the addition of the
quadrupole to the analysis allows for significant improvements on the
determination of the model parameters and specifically on $f$, similarly to the
power spectrum case. Finally, we compare our numerical estimate for the full
covariance with its theoretical prediction in the Gaussian approximation and
find the latter to work remarkably well in the context of simulation boxes with
periodic boundary condition.
