Reheating constraints on Tachyon Inflation
  Tachyon inflation is one of the most attractive models of noncannonical
inflation motivated by string theory. In this work we revisit the constraints
on tachyon inflation with inverse $\cosh$ potential and exponential potential
considering reheating, Although the phase of reheating is not well understood,
it can be parameterized in terms of reheating temperature $T_{re}$, number of
e-folds during reheating $N_{re}$ and effective equation of state during
reheating $w_{re}$, which can be related to the parameters of the tachyon
potential, spectral index $n_s$ and tensor-to-scalar ratio $r$. For various
reheating scenarios there is a finite range of $w_{re}$ and the reheating
temperature should be above electroweak scale. By imposing these conditions, we
find that both the inverse $\cosh$ potential and exponential potential are
disfavored by Planck observations. We also find that $w_{re}$ for both these
potentials should be close to $1$ to satisfy Planck-2015 joint constraints on
$n_s$ and $r$.
