ISM spectrum by cosmic dust?

Abstract

The interstellar medium (ISM) spectrum is usually explained by the response of dust particles (DPs) to the absorption of ultraviolet (UV) and visible (VIS) photons from nearby stars. With regard to the unidentified infrared (UIR) bands, the DPs are thought heated by UV and VIS photons to about 100 K thereby exciting the polycyclic aromatic hydrocarbons (PAHs). However, the UIR bands may be explained with the DPs at 2.7 K. To wit, the UIR bands form by the direct excitation of PAHs by infrared (IR) radiation induced from the absorption of cosmic microwave background (CMB) radiation in DPs by quantum electrodynamics (QED). © 2008 International Astronomical Union.