黑暗物質與星系團中的無線電暈; Dark Matter and Radio Halos in Galaxy Clusters

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題名:	黑暗物質與星系團中的無線電暈;Dark Matter and Radio Halos in Galaxy Clusters
作者:	郭炳宏
貢獻者:	天文學研究所
關鍵詞:	星系團;無線電暈;相對論性電子;黑暗物質;galaxy cluster;radio halo;relativistic electron;dark matter;物理類
日期:	2008-07-01
上傳時間:	2010-12-28 15:27:58 (UTC+8)
出版者:	行政院國家科學委員會
摘要:	根據現今的觀測資料，星系團含有無線電暈的比例只約為35%；所以，含有無線電暈在所有星系團中並不是一個「普遍」的現象。這些存在於星系團中的無線電暈，已確定是由相對論性電子在磁場中運動的同步輻射所產生。但是這些相對論性電子的來源至今尚未清楚。其中比較被科學界接受的，有相對論性電子再加速模型與次電子模型。近年來，有人提出星系團中產生無線電暈的相對論性電子，可能是由neutralino 相互碰撞所產生。由於黑暗物質是構成星系團的主要元素而且neutralino 是眾多黑暗物質候選粒子名單上，被認為是很有可能的粒子之ㄧ，所以此模型已引起相當的重視。然而，文獻中提出無線電暈的黑暗物質模型的論文，皆只針對某單一具有無線電暈的星系團（尤其是 Coma 星系團）來研究。所以，我想以（1）無線電暈的Radio Power 與星系團的X-ray Luminosity 之關係、（2）結合具有無線電暈的星系團A401 與沒有無線電暈的星系團A119 對此模型的限制、與（3）具有無線電暈的星系團在所有星系團中所佔有的比例，三個方向來研究與檢驗無線電暈的黑暗物質模型。 Observations have found the percentage of galaxy clusters possessing radio halos is only about 35%. Thus possessing a radio halo is not a 「popular」 phenomenon in galaxy clusters. The radio halos are believed due to the synchrotron radiation of relativistic electrons. However, where the relativistic electrons come from is still unclear. Among the models for the source of the relativistic electrons, reacceleration models and secondary electron models are generally considered. Recently, a dark matter model has been proposed for the source of the relativistic electrons. This model suggests that the relativistic electrons are produced by the collisions between neutralinos. Since dark matter is the main component constituting galaxy clusters and neutralinos are the most promising candidate for dark matter, this dark matter model for radio halos has caught some attention. However, the papers suggesting the dark matter model for radio halos focused on one specific galaxy cluster only, especially Coma. Thus I will study and examine the dark matter model for radio halos by general properties of radio halos: (1) the P1.4GHz -LX relation, (2) the constraints from A401 (with a radio halo) and A119 (without a radio halo), and (3) the percentage of galaxy clusters possessing radio halos at different redshifts if the model was correct. 研究期間：9608 ~ 9707
關聯:	財團法人國家實驗研究院科技政策研究與資訊中心
顯示於類別:	[天文研究所] 研究計畫

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