The impact of JWST broad-band filter choice on photometric redshift
  estimation
  The determination of galaxy redshifts in James Webb Space Telescope (JWST)'s
blank-field surveys will mostly rely on photometric estimates, based on the
data provided by JWST's Near-Infrared Camera (NIRCam) at 0.6-5.0 {\mu}m and Mid
Infrared Instrument (MIRI) at {\lambda}>5.0 {\mu}m. In this work we analyse the
impact of choosing different combinations of NIRCam and MIRI broad-band filters
(F070W to F770W), as well as having ancillary data at {\lambda}<0.6 {\mu}m, on
the derived photometric redshifts (zphot) of a total of 5921 real and simulated
galaxies, with known input redshifts z=0-10. We found that observations at
{\lambda}<0.6 {\mu}m are necessary to control the contamination of high-z
samples by low-z interlopers. Adding MIRI (F560W and F770W) photometry to the
NIRCam data mitigates the absence of ancillary observations at {\lambda}<0.6
{\mu}m and improves the redshift estimation. At z=7-10, accurate zphot can be
obtained with the NIRCam broad bands alone when S/N>=10, but the zphot quality
significantly degrades at S/N<=5. Adding MIRI photometry with one magnitude
brighter depth than the NIRCam depth allows for a redshift recovery of 83-99%,
depending on SED type, and its effect is particularly noteworthy for galaxies
with nebular emission. The vast majority of NIRCam galaxies with [F150W]=29 AB
mag at z=7-10 will be detected with MIRI at [F560W, F770W]<28 mag if these
sources are at least mildly evolved or have spectra with emission lines
boosting the mid-infrared fluxes.
