|19th of January 2017|
|Unveiling the interstellar gas associated with the superbubble 30 Doradus C|
|by Hidetoshi Sano (Nagoya University)|
|Superbubble 30 Doradus C is a bright X-ray cavity with a diameter of ~300 light year in the Large Magellanic Cloud, which was created by the shockwaves of multiple supernovae and stellar winds from the massive stars. Although it has well studied at multiwavelength from radio to X- and gamma-rays, the interstellar gas associated with the superbubble has not been identified. |
Using the Mopra radio telescope and the archival data of the Australia Telescope Compact Array, an international team of astronomers has discovered the interstellar molecular and atomic clouds associated with 30 Doradus C. They identified five molecular clouds and three atomic clouds along with the X-ray shell of 30 Doradus C. The synchrotron X-rays are significantly enhanced around the molecular clouds, whereas the thermal X-rays are bright in the region where has no dense interstellar neutral gas.
The authors discussed that the synchrotron X-ray shell was created by at least several supernovae within a few thousand years, and the X-ray enhancement is possibly due to the magnetic field amplification around the molecular clumps via shock-cloud interaction. Moreover, they deduced that the Cherenkov Telescope Array could detect and resolve gamma-ray flux associated with the molecular cloud, which means to identify the acceleration site of the cosmic-ray protons.
Figure captions: Multiwavelength images of the superbubble 30 Doradus C, indicating (a) X-rays (red: 0.5-1.2 keV, green: 1.2-2.0 keV, blue: 2.0-7.0 keV), (b) molecular clouds, and (c) atomic clouds distributions. Superposed white contours represent the synchrotron X-rays in the energy band of 2.0-7.0 keV. Symbols of circle and diamond indicate the O-tyep and WR stars.
Reference: H. Sano, Y. Yamane, F. Voisin, K. Fujii, S. Yoshiike, T. Inaba, K. Tsuge, Y. Babazaki, I. Mitsuishi, R. Yang, F. Aharonian, G. Rowell, M. D. Filipovic, N. Mizuno, K. Tachihara, A. Kawamura, T. Onishi, and Y. Fukui, 2017, Submitted to The Astrophysical Journal (astro-ph:1701-01962).