Mapping Cassiopeia A's silicon/sulfur Doppler velocities with XRISM-Resolve
Mapping Cassiopeia A's silicon/sulfur Doppler velocities with XRISM-Resolve
Young supernova remnants (SNRs) provide crucial insights into explosive nucleosynthesis products and their velocity distribution soon after the explosion. However, these velocities are influenced by the dynamics of the circumstellar medium (CSM), which originates from the progenitor's late-phase mass loss. Cas A, the youngest known Galactic core-collapse SNR, was studied to analyze the spatial distribution of Si and S radial velocities using two high-spectral resolution observations from the XRISM-Resolve imaging spectrometer.Resolve's capabilities enabled the detailed characterization of Si XIII, Si XIV, S XV, and S XVI lines, whose line shapes can be resolved and modeled using Gaussian radial-velocity components. The radial velocities measured generally align with previous CCD-based results, confirming that they were not artifacts caused by blended lines or ionization variations. Modeling line profiles with two-component Gaussians improved fits in some regions, revealing distinct redshifted (backside) and blueshifted (frontside) components only in a few specific areas. In most regions, however, both components were either both redshifted (northwest) or both blueshifted (southeast), consistent with the patchy ejecta shell morphology seen in optically emitting fast-moving knots. The individual line components revealed a line broadening ranging from $\sigma_v \approx 200$ to $\sigma_v \approx 2000$ km/s. Components with $1000 \lesssim \sigma_v \lesssim 2000$km/s are consistent with previously determined reverse shock velocities, suggesting non-equilibrated or partially equilibrated ion temperatures. Narrow components with small radial velocities found near Cas A's projected center likely originate from shocked CSM plasma. But the low radial velocity and small $\sigma_v$ defies identifying these components with either the frontside or backside of the SNR, or both.
Makoto Sawada、Haruto Sonoda、Shunsuke Suzuki、Dai Tateishi、Yukikatsu Terada、Hiroyuki Uchida、Koji Mori、Hiroshi Murakami、Hiroshi Nakajima、Toshiki Sato、Jacco Vink、Manan Agarwal、Aya Bamba、Liyi Gu、Paul Plucinsky、Ehud Behar、Lia Corrales、Adam Foster、Shin-ichiro Fujimoto、Masahiro Ichihashi、Kazuhiro Ichikawa、Satoru Katsuda、Hironori Matsumoto、Kai Matsunaga、Tsunefumi Mizuno
Department of Physics, Rikkyo University, Tokyo, JapanISAS/JAXA, Sagamihara, Kanagawa, JapanISAS/JAXA, Sagamihara, Kanagawa, JapanDepartment of Physics, Graduate School of Science, The University of Tokyo, JapanGraduate School of Science and Engineering, Saitama University, Saitama, JapanDepartment of Physics, Kyoto University, Kyoto, JapanFaculty of Engineering, University of Miyazaki, Miyazaki, JapanDepartment of Data Science, Tohoku Gakuin University, Miyagi, JapanCollege of Science and Engineering, Kanto Gakuin University, Kanagawa, JapanSchool of Science and Technology, Meiji University, Kanagawa, JapanAnton Pannekoek Institute/GRAPPA, University of Amsterdam, NetherlandsAnton Pannekoek Institute/GRAPPA, University of Amsterdam, NetherlandsDepartment of Physics, Graduate School of Science, The University of Tokyo, JapanSRON Netherlands Institute for Space Research, Leiden, NetherlandsHarvard-Smithsonian Center for Astrophysics, Cambridge MA, USADepartment of Physics, Technion, Technion City, Haifa, IsraelDepartment of Astronomy, University of Michigan, USAHarvard-Smithsonian Center for Astrophysics, Cambridge MA, USANational Institute of Technology Kumamoto College, Kumamoto, JapanDepartment of Physics, Graduate School of Science, The University of Tokyo, JapanFaculty of Engineering, University of Miyazaki, Miyazaki, JapanGraduate School of Science and Engineering, Saitama University, Saitama, JapanDepartment of Earth and Space Science, Osaka University, Osaka, JapanDepartment of Physics, Kyoto University, Kyoto, JapanDepartment of Physics, Hiroshima University, Hiroshima, Japan
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Makoto Sawada,Haruto Sonoda,Shunsuke Suzuki,Dai Tateishi,Yukikatsu Terada,Hiroyuki Uchida,Koji Mori,Hiroshi Murakami,Hiroshi Nakajima,Toshiki Sato,Jacco Vink,Manan Agarwal,Aya Bamba,Liyi Gu,Paul Plucinsky,Ehud Behar,Lia Corrales,Adam Foster,Shin-ichiro Fujimoto,Masahiro Ichihashi,Kazuhiro Ichikawa,Satoru Katsuda,Hironori Matsumoto,Kai Matsunaga,Tsunefumi Mizuno.Mapping Cassiopeia A's silicon/sulfur Doppler velocities with XRISM-Resolve[EB/OL].(2025-05-07)[2025-07-16].https://arxiv.org/abs/2505.04691.点此复制
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