Abstract
The massive stellar cluster Cl* 1806-20 and the supernova remnant (SNR) G9.7-0.0 are potentially important sites of cosmic-ray acceleration. In this work, we analyze the 14.4 yr Fermi-LAT data to investigate the GeV gamma-ray feature in their sky region. With gamma-ray spatial analyses, we identify a number of components. Src-E is spatially coincident with the known TeV source HESS J1808-204 which is enclosing Cl* 1806-20. The 550 MeV LAT spectrum of Src-E is smoothly connected with the TeV spectrum of HESS J1808-204, without an indication of a turnover. This demonstrates a possible physical association between the GeV—TeV gamma- rays and the stellar cluster. Src-W is spatially coincident with an OH maser adjacent to SNR G9.7-0.0 (i.e. the orientation of SNR interaction with molecular clouds). The 0.3–20 GeV spectrum of Src-W follows a power -law with a soft photon index of ~2.9, suggesting an extremely old age of >30 kyr for SNR G9.7-0.0. Src-S is at the southeast of the SNR. Src-S demonstrates a “quasi-monoenergetic” spectrum with a sharp peak at ~2.8 GeV. For this, we propose a scenario where the secondary cosmic-ray nuclei escaping from the SNR interact with the circumstellar medium formed from the progenitor's winds.
Biography
Paul K. H. Yeung graduated with a PhD degree from University of Hamburg, Germany. He has 8-year experience in High-Energy Astrophysics research. He is currently a postdoctoral research fellow in Institute for Cosmic Ray Research (ICRR), The University of Tokyo, Japan. He has been working on TeV gamma-ray data as a member of CTA Collaboration and MAGIC Collaboration.
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