A model independent constraint on the temporal evolution of the speed of
  light
  We present a new, model-independent method to reconstruct the temporal
evolution of the speed of light $c(z)$ using astronomical observations. After
validating our pipeline using mock datasets, we apply our method to the latest
BAO and supernovae observations, and reconstruct $c(z)$ in the redshift range
of $z\in[0,1.5]$. We find no evidence of a varying speed of light, although we
see some interesting features of $\Delta c(z)$, the fractional difference
between $c(z)$ and $c_0$ (the speed of light in SI), \eg, $\Delta c(z)<0$ and
$\Delta c(z)>0$ at $0.2\lesssim z\lesssim0.5$ and $0.8\lesssim z\lesssim1.3$,
respectively, although the significance of these features is currently far
below statistical importance.
