THE DIFFUSE INTERSTELLAR BANDS IN HISTORY AND IN THE UV

The diffuse interstellar bands (DIBs) have been known of since 1922, but their carrier molecules remain unidentified to this day. We present a brief history of DIB observations, followed by a list of constraints any suggested origin must face, and finally a preview of current research for ultraviolet DIBs using the Cosmic Origins Spectrograph on the Hubble Space Telescope. We conclude that PAHs are consistent with all the listed constraints, but that PAHs may not be the only molecular species responsible for the DIBs.