A systematic study of Galactic infrared bubbles along the whole Galactic plane with the AKARI all-sky surveys

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

Galactic infrared (IR) bubbles are known to contain massive stars near their centers, and crucial to study massive star formation mechanisms. In our previous study (Hattori et al. 2016), IR bubbles located in inner Galactic regions (absolute value of l less than or equal to 65 deg, absolute value of b less than or equal to 1 deg) are classified into broken and closed bubbles, depending on their morphologies, to find that the broken bubbles are indicative of cloud-cloud collision. We expand the previous study to the whole Galactic plane using the AKARI all-sky survey data. We limit our study on large (R greater than 1') bubbles to reliably identify and classify them even in outer Galactic regions and relatively high-latitude regions where neither Spitzer nor Herschel data are available. As a result, we newly discover about 100 Galactic IR bubbles in outer Galactic regions (absolute value of l greater than 65 deg, absolute value of b less than or equal to 5 deg). We find that a significantly higher fraction of bubbles are classified into broken ones in outer Galactic regions than in inner Galactic regions. Following the same procedure as in Hattori et al. (2016), we also examine the properties of the bubbles, decomposing their spectral energy distributions consisting of AKARI and Herschel photometric data with a dust model. In the paper, we show the result of our comparative study on the properties of the Galactic IR bubbles between the inner and outer Galactic regions, and discuss the cause of their systematic difference.

形態: カラー図版あり

Physical characteristics: Original contains color illustrations

資料番号: AA1730026061

レポート番号: JAXA-SP-17-009E