Abstract
We investigate how much can be learnt about four types of primordial
non-Gaussianity (PNG) from small-scale measurements of the halo field. Using
the quijote-png simulations, we quantify the information content
accessible with measurements of the halo power spectrum monopole and
quadrupole, the matter power spectrum, the halo-matter cross spectrum and the
halo bispectrum monopole. This analysis is the first to include small,
non-linear scales, up to $k_max=0.5 h/Mpc$, and to explore
whether these scales can break degeneracies with cosmological and nuisance
parameters making use of thousands of N-body simulations. For local PNG,
measurements of the scale dependent bias effect from the power spectrum using
sample variance cancellation provide significantly tighter constraints than
measurements of the halo bispectrum. In this case measurements of the small
scales add minimal additional constraining power. In contrast, the information
on equilateral and orthogonal PNG is primarily accessible through
the bispectrum. For these shapes, small scale measurements increase the
constraining power of the halo bispectrum by up to $\times4$, though the
addition of scales beyond $k0.3 h/Mpc$ improves constraints
largely through reducing degeneracies between PNG and the other parameters.
These degeneracies are even more powerfully mitigated through combining power
spectrum and bispectrum measurements. However even with combined measurements
and small scale information, equilateral non-Gaussianity remains highly
degenerate with $\sigma_8$ and our bias model.
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