{"title":"Measurement of temperature relaxation in the postshock plasma of the northwestern limb of SN 1006","authors":"Masahiro Ichihashi, Aya Bamba, Yuichi Kato, Satoru Katsuda, Hiromasa Suzuki, Tomoaki Kasuga, Hirokazu Odaka, Kazuhiro Nakazawa","doi":"10.1093/pasj/psae049","DOIUrl":null,"url":null,"abstract":"Heating of charged particles via collisionless shocks, while ubiquitous in the universe, is an intriguing yet puzzling plasma phenomenon. One outstanding question is how electrons and ions approach an equilibrium after they were heated to different immediate-postshock temperatures. In order to fill the significant lack of observational information of the downstream temperature-relaxation process, we observe a thermal-dominant X-ray filament in the northwest of SN 1006 with Chandra. We divide this region into four layers with a thickness of $15^{\\prime \\prime }$ or $0.16\\:$pc each, and fit each spectrum by a non-equilibrium ionization collisional plasma model. The electron temperature was found to increase toward downstream from 0.52–0.62 to 0.82–$0.95\\:$keV on a length scale of $60^{\\prime \\prime }$ (or $0.64\\:$pc). This electron temperature is lower than thermal relaxation processes via Coulomb scattering, requiring some other effects such as plasma mixture due to turbulence and/or projection effects, etc., which we hope will be resolved with future X-ray calorimeter missions such as XRISM and Athena.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":null,"pages":null},"PeriodicalIF":2.2000,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Publications of the Astronomical Society of Japan","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1093/pasj/psae049","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Heating of charged particles via collisionless shocks, while ubiquitous in the universe, is an intriguing yet puzzling plasma phenomenon. One outstanding question is how electrons and ions approach an equilibrium after they were heated to different immediate-postshock temperatures. In order to fill the significant lack of observational information of the downstream temperature-relaxation process, we observe a thermal-dominant X-ray filament in the northwest of SN 1006 with Chandra. We divide this region into four layers with a thickness of $15^{\prime \prime }$ or $0.16\:$pc each, and fit each spectrum by a non-equilibrium ionization collisional plasma model. The electron temperature was found to increase toward downstream from 0.52–0.62 to 0.82–$0.95\:$keV on a length scale of $60^{\prime \prime }$ (or $0.64\:$pc). This electron temperature is lower than thermal relaxation processes via Coulomb scattering, requiring some other effects such as plasma mixture due to turbulence and/or projection effects, etc., which we hope will be resolved with future X-ray calorimeter missions such as XRISM and Athena.
期刊介绍:
Publications of the Astronomical Society of Japan (PASJ) publishes the results of original research in all aspects of astronomy, astrophysics, and fields closely related to them.