IoA Seminar 2022 / 令和4年度/2022年度 東京大学天文学教育研究センター・天文学教室合同談話会 †本談話会について †趣旨 †東京大学・天文学教育研究センターでは2003年4月から談話会を開いています。
2021年度より当面のあいだ, 天文学教室と天文学教育研究センター合同での開催となっております。 定例日時 †
場所 †
世話人(天文センター) †ML: semiadm _at_ ioa.s.u-tokyo.ac.jp please replace _at_ with @
天文学教室談話会について †
Upcoming Seminars †No. 384: †Speaker: Paul K. H. Yeung(Department of Physics, The University of Tokyo) †Title: Cosmic-ray Acceleration & Escape from Intermediate-Aged Supernova Remnant Kes 79 †Language: English Abstract: Hadronic γ-ray sources of supernova remnant — molecular cloud (SNR–MC) interactions can serve as stopwatches for the escape of cosmic rays (CRs) from SNRs, which gradually develops from highest-energy particles to lowest-energy particles with time. Recent multiwavelength studies confirmed the interaction of the intermediate-aged SNR Kes 79 with molecular clouds. In this work, we analyze the 11.5 yr Fermi-LAT data to investigate the γ-ray feature in/around the Kes 79 region. With ≥5 GeV data, we detect two extended sources: Src-N (the brighter one; radius ≈0.31°) concentrated at the north of the SNR while enclosing a powerful pulsar — PSR J1853+0056, and Src-S (radius ≈0.58°) concentrated at the south of the SNR. Their spectra have distinct peak energies (≈1.0 GeV for Src-N and ≲0.5 GeV for Src-S), suggesting different origins for them. In our hadronic model that includes the leaked cosmic rays (CRs) from the shock-cloud collision, even with extreme values of parameters, SNR Kes 79 can by no means provide enough CRs reaching clouds at Src-N to explain the local GeV spectrum. We propose that the Src-N emission could be predominantly reproduced by a putative pulsar wind nebula powered by PSR J1853+0056. On the other hand, our same hadronic model can reproduce a majority of the GeV emission at Src-S with typical values of parameters. Also, SNR Kes 79's relatively softer γ-ray spectrum peaked at a relatively lower energy is in agreement with its intermediate age, based on the modelled evolution of cosmic-ray escape from an SNR. 今後の講演予定 †
終了した談話会(2022年度) †詳細はこちら: 令和4(2022)年度談話会
これまでの談話会 †
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