Calibrating the James Webb Space Telescope filters as star formation
  rate indicators
  We have calibrated the 6.5 m James Webb Space Telescope (JWST) mid-infrared
filters as star formation rate indicators, using JWST photometry synthesized
from $Spitzer$ spectra of 49 low redshift galaxies, which cover a wider
luminosity range than most previous studies. We use Balmer decrement corrected
$\rm{H\alpha}$ luminosity and synthesized mid-infrared photometry to
empirically calibrate the $Spitzer$, WISE and JWST filters as star formation
rate indicators. Our $Spitzer$ and WISE calibrations are in good agreement with
recent calibrations from the literature. While mid-infrared luminosity may be
directly proportional to star formation rate for high luminosity galaxies, we
find a power-law relationship between mid-infrared luminosity and star
formation rate for low luminosity galaxies ($L_{\rm H\alpha} \leq 10^{43}~{\rm
erg~s^{-1}}$). We find that for galaxies with a $\rm{H\alpha}$ luminosity of
$\rm{10^{40}}~erg~s^{-1}$ (corresponding to a star formation rate of $\sim
0.055~{\rm M_\odot~yr^{-1}}$), the corresponding JWST mid-infrared $\nu
L_{\nu}$ luminosity is between $\rm{10^{40.50}}$ and
$\rm{10^{41.00}}~erg~s^{-1}$. Power-law fits of JWST luminosity as a function
of $\rm{H\alpha}$ luminosity have indices between 1.17 and 1.32. We find that
the scatter in the JWST filter calibrations decreases with increasing
wavelength from 0.39 to 0.20 dex, although F1000W is an exception where the
scatter is just 0.24 dex.
