• Godard, Marie
• Dartois, Emmanuel

Abstract

International audience ; Hydrogenated amorphous carbons (a-C:H) have proved to be excellent analogs of interstellar dust through IR vibrational absorption bands (3.4 µm, 6.8 µm and 7.2 µm bands (respectively 2960 cm-1 , 1460 cm-1 and 1380 cm-1)) widely observed in galaxies diffuse interstellar medium (ISM). a-C:H are candidates for one of the observed interstellar dust features : a large emission band in the red part of the visible spectrum, attributed to photoluminescence (PL) of interstellar dust, and called the extended red emission (ERE). The PL absolute quantum yield is one of the strongest constraints set by such ERE observations. The PL relative quantum yield is known and measured for many a-C:H at discrete excitation wavelengths. The few absolute efficiencies determined are scattered and sometimes vary by orders of magnitude for supposedly identical a-C:H. We thus produce astrophysical a-C:H and analyze their PL and IR behavior, carefully accounting for thin film optical effects. By properly determining the excitation wavelength dependent PL absolute quantum yields for a wide variety of astrophysically relevant a-C:H, we can constrain these interstellar dust analogs as possible ERE candidates.

Topics

• impedance spectroscopy
• photoluminescence
• amorphous
• Carbon
• thin film