Non-Gaussian signatures of Tachyacoustic Cosmology
  I investigate non-Gaussian signatures in the context of tachyacoustic
cosmology, that is, a noninflationary model with superluminal speed of sound. I
calculate the full non-Gaussian amplitude $\mathcal{A}$, its size $f_{\rm NL}$,
and corresponding shapes for a red-tilted spectrum of primordial scalar
perturbations. Specifically, for cuscuton-like models I show that $f_{\rm
NL}\sim {\cal O}(1)$, and the shape of its non-Gaussian amplitude peaks for
both equilateral and local configurations, the latter being dominant. These
results, albeit similar, are quantitatively distinct from the corresponding
ones obtained by Magueijo {\it{et. al}} in the context of superluminal bimetric
models.
