PAHs in Astrophysics

Polycyclic aromatic hydrocarbon (PAH) molecules reveal their presence in a wide variety of astrophysical regions by emitting a distinct series of spectral features at 3.3, 6.2, 7.7, 8.6, 11.3 and 12.7 micrometer. They play an essential role in the interstellar physical and chemical processes including the photoelectric heating of interstellar gas, the formation of H_2, and the obscuration of ultraviolet starlight. They are a powerful tool for probing the physical condition of the regions where they are found. I will review the recent development in the physics and astrophysics of PAHs and the future perspectives in the JWST era.