TA-Lab. Colloquium

(Last update on 10th April 2026)

Next Talk

Date/Room 23 April at 14:00 in ES606
Speaker Prof. Hidehiro Kaneda (Uir-Lab., Nagoya Univ.)
Title Organic matter in space: Polycyclic Aromatic Hydrocarbons (PAHs)
Abstract I will give a lecture on the fundamentals of PAHs for the members of Ta Lab. In the near- and mid-infrared wavelength range, there are many important spectral bands of dust particles such as silicates, carbonaceous grains, and ices. Among them, emission features due to polycyclic aromatic hydrocarbons (PAHs) are ubiquitously observed in the interstellar space including not only photo-dissociation regions, which are widely distributed around star-forming regions in a galaxy, but also regions of rather quiescent or even harsh interstellar environments. Their spectral inter-band ratios are known to significantly vary from galaxy to galaxy or from region to region within a galaxy, mainly depending their ionization states and/or size distributions which reflect the interstellar conditions. The profiles of the PAH features, such as peak positions and widths, also vary, providing us with information on the properties of the interstellar medium in a galaxy. In my lecture, I briefly review the observational history of PAHs since their discovery and explain how to interpret their spectral features based on our observational results obtained with Spitzer, AKARI, and JWST.