THz Low Resolution Spectroscopy for Astronomy

The THz spectral regime provides a wide range of spectral lines that are invaluable probes of star formation and AGN activity in galaxies both in the local Universe and at the earliest times. We review the utility of these lines, give examples of the science they deliver, and detail the properties of successful low resolution direct detection spectrometers for work in the THz regime. We finish with a discussion of the exciting new science we expect with the next direct detection generation spectrometers on new facilities such as SOFIA, CCAT, SPICA, and ALMA.