{"title":"SN 1006 西北边缘震后等离子体的温度弛豫测量","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":"6 1","pages":""},"PeriodicalIF":2.2000,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"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\":\"6 1\",\"pages\":\"\"},\"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}","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
摘要
通过无碰撞冲击加热带电粒子的现象在宇宙中无处不在,是一种有趣而又令人费解的等离子现象。一个悬而未决的问题是,电子和离子在被加热到不同的冲击后即时温度后,是如何接近平衡的。为了填补关于下游温度缓和过程的观测信息的巨大缺失,我们用钱德拉观测到了 SN 1006 西北部的一个热主导 X 射线灯丝。我们把这个区域分成了四层,每层厚度为15^{\prime \prime }$或0.16\:$pc,并用非平衡电离碰撞等离子体模型拟合了每一层的光谱。结果发现,在 60^{\prime \prime }$ (或 $0.64\:$pc)的长度尺度上,电子温度从 0.52-0.62 keV 上升到 0.82-$0.95\:$keV。这一电子温度低于通过库仑散射产生的热弛豫过程,需要一些其他效应,如湍流和/或投影效应导致的等离子体混合物等,我们希望未来的X射线量热计任务(如XRISM和雅典娜)能够解决这些问题。
Measurement of temperature relaxation in the postshock plasma of the northwestern limb of SN 1006
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.