Reading the Message in the Light: JWST IR to UV Spectroscopy at Low to High Redshift

The spectrometers on board JWST will detect UV through IR radiation emitted by objects over a broad range of redshift. They will offer unprecedented NIR observations of the local universe, and, at high redshift, probe optical/UV spectral regions that are now studied at now redshift with HST. I propose to enhance the spectral simulation code Cloudy, which predicts this emission from atoms and molecules by solving the equations describing the non-equilibrium thermal, chemical, ionization, excitation, and radiative transfer, to predict the spectrum JWST will detect in a broad range of objects and redshifts. The regions JWST will detect at low redshift will tend to be the dusty, atomic and molecular regions associated with star formation and evolution, perhaps on galaxy-wide scales. High-z observations, at shorter wavelengths in the rest frame, will tend to active galactic nuclei, starbursts, and very young protogalaxies. Cloudy can model a wide range of environments including the local ISM, accreting matter near black holes, starburst galaxies, and active galactic nuclei, because it works from first principles, going back to basic atomic and molecular microphysics. Roughly three hundred papers cite Cloudy’s documentation each year, a testament to its wide use.