Seminar:- Examining a hadronic γ-ray scenario for the radiative shell and molecular clouds of the old GeV supernova remnant G298.6-0.0
Based on the 13.7 yr Fermi-LAT data, the speaker and his research team claimed detection of two γ-ray sources (namely Src-NE and Src-NW) associated with the SuperNova Remnant(SNR) G298.6-0.0, and interpreted it as an old GeV SNR interacting with Molecular Clouds(MCs). They reported their γ-ray spectral fittings and cosmic-ray phenomenology in a hadronic scenario, considering both the shell and MC regions of SNR G298.6-0.0. They confirm that the γ-ray spectra of both Src-NE and Src-NW exhibit spectral breaks, at ~1.50 and ~0.68 GeV, respectively. Src-NW has a harder broad-band photon index than Src-NE, suggesting an appreciable difference between the physical separations of their respective emission sites from SNR G298.6-0.0. The cosmic-ray spectrum responsible for Src-NE starts with a minimum energy of ~1.38 GeV, and has a proton index of ~2.57 below the exponential cutoff energy of ~240 GeV. Accordingly, they argue that Src-NE is dominated by the SNR shell, while only a minor portion of lower-energy emission is contributed by the MCs interacting with the SNR. The cosmic-ray population for Src-NW starts at a higher energy such that the ECR, min ratio of Src-NW to Src-NE is ≳2. The high ECR, min, as well as the high cosmic-ray energy density required (~26 eV cm⁻³), supports the interpretation that Src-NW is predominantly the γ-ray emission from the farther MCs being bombarded by protons that had earlier escaped from SNR G298.6-0.0. By comparing the high-energy features of G298.6-0.0 with those of analogical SNRs, especially SNR W 28 and SNR W 44, they further constrain the age of SNR G298.6-0.0 to be 10~30 kyr, under the assumption of a purely hadronic scenario.
時間：2024.06.26(三) 14:30
地點：香港大學 莊月明物理樓* 522室
講者：Dr. Paul YEUNG K. H. (日本 東京大学**)
語言：英語
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【此屬轉載信息，以主事單位發布為準】
*Chong Yuet Ming Physics Building
**The University of Tokyo
此活動由香港大學物理系主辦。
https://www.physics.hku.hk/news_and_events/upcoming/20240626-py
