Processing of hydrocarbon dust in star-forming galaxies revealed with AKARI

第4回「あかり」国際会議 (2017年10月17-20日. 東京大学), 文京区, 東京

The 4th AKARI International Conference: The Cosmic Wheel and the Legacy of the AKARI archive: from galaxies and stars to planets and life (October 17-20, 2017. The University of Tokyo), Bunkyo-ku, Tokyo, Japan

Hydrocarbon dust is one of the dominant components of interstellar dust, which mainly consists of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons. While hydrocarbon dust is thought to be processed in interstellar radiation fields or shocks, detailed processing mechanisms are not completely understood yet. Therefore, we study the infrared spectral properties of hydrocarbon dust for 138 pure star-forming galaxies at redshift z less than 0.3. Using near-infrared spectra (2.5-5 micrometers) obtained with AKARI/IRC, we derived the luminosities of the aromatic hydrocarbon feature at 3.3 micrometers(L(sub aromatic)) and the aliphatic hydrocarbon feature at 3.4-3.6 micrometers (L(sub aliphatic)). We also derived the total infrared luminosity (L(sub IR)), the total PAH luminosity (L(sub PAH)) and the radiation field strength by modeling the spectral energy distributions of the sample galaxies with AKARI, IRAS, and WISE photometry data. We find that L(sub aliphatic)/L(sub IR) decreases with L(sub IR), like L(sub PAH)/L(sub IR) shown in previous studies. Moreover, we find that L(sub aliphatic)/L(sub aromatic) decreases with L(sub IR), indicating that aliphatic hydrocarbons are more highly processed than aromatic hydrocarbons. In this paper, we discuss possible processing mechanisms of interstellar hydrocarbon dust in galaxies with higher L(sub IR).

形態: カラー図版あり

Physical characteristics: Original contains color illustrations

資料番号: AA1730026016

レポート番号: JAXA-SP-17-009E