{"created":"2023-06-20T13:20:24.927087+00:00","id":430,"links":{},"metadata":{"_buckets":{"deposit":"ca225933-dcf5-45ef-99f0-b81492bfd3ee"},"_deposit":{"created_by":1,"id":"430","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"430"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00000430","sets":["2:427:11"]},"author_link":["0","0","0"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"永井, 洋"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"ナガイ, ヒロシ"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2007-03-23"}]},"item_1_degree_grantor_5":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"総合研究大学院大学"}]}]},"item_1_degree_name_6":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"Compact Symmetric Objects（CSOs）are proved to be young radio sources from both the kinematic- and synchrotron－aging studies．<br />　　With　Very Long Baseline Array（VLBA）observations for CTD 93 over 8.5 yr，we detected an　increase of separation between the hot spot and the counter hot spot. The separation rate along the　source axis is 0.34&plusmn;0.11<i> c</i>, which results in a kinematic age of 2200&plusmn;700 yr. Assuming that two hot　spots are moving apart from the core at equal speeds，we derive an advance velocity of 0.17&plusmn;0.06<i>c.</i>On the other hand, our multi-frequency observations revealed that radio－lobe spectra show a high-　frequency steepening due to synchrotron aging. The spectral break decreases with distance from the　hot spot. This tendency is expected from the basic scenario of radio lobe evolution involving particle　acceleration at the hotspots，With the radio lobe populated by high－energy electrons that have leaked　our from the hot spots. From the spectral fit in the radio lobe of CTD 93 under the minimum－energy　assumption, we derive the advance velocity of 0.232&plusmn;0.005<i>c</i> and synchrotron age of 1720&plusmn;40 yr. The　kinematic age and synchrotron age show an agreement within a factor of two．<br />　　Following the detection of hot－spot motion and spectral break in CTD 93，we examined both　kinematic and synchrotron ages of the innermost radio source of 3 C 84 using VLBA．Since 3C 84 is　One of the nearest powerful CSOs，detailed kinematics and spatial distribution of break frequency are　revealed. Measurements of hot spot motion with respect to the core over 4.5 yr resulted in the advance　velocity of 0.43&plusmn0.06<i>c</i>. The resultant kinematic age is 33&plusmn;5 yr in 2000. The radio－lobe spectra also　show a high-frequency steepening due to synchrotron aging．The break frequency decreases with the　distance from the hot spot. The lowest break frequency of 2.3&plusmn;1.4 GHz is occurred near the core．　Assuming the minimum－energy field，we derive the synchrotron age of 24&plusmn;<sup>14</sup><sub>5</sub> yr in 1995．The kinematic　and synchrotron ages are thus in very good agreement. Also these ages indicate that innermost radio　lobe is associated with the 1959 outburst of activity.<br />　　We proved that CTD 93 and 3C 84 are young radio sources from both kinematic－and synchrotron-　aging studies. This is strong evidence for the hypothesis that CSOs are young radio sources. As well，　the agreements between kinematic and synchrotron ages imply a validity of synchrotron－aging analysis　under the minimum－energy assumption in CSOs. Assuming that minimum－energy assumption is also　applicable to FRⅡsources，we found that an averaged expansion velocity of FRⅡ sources is ～0.05<i>c</i>.　 This is comparable to an averaged CSOs’ expansion velocity of ～0.1<i>c</i>. This implies that expansion 　velocity of radio lobe  does not strongly depend on the linear size of radio source, if we allow that　CSOs evolve into FRⅡsources.<br />　　Finally，we examined the physical property of hot spots for a large number of radio galaxies to　reveal the relation among CSOs，MSOs，and FRⅡ sources. The hot spot luminosity of CSOs and　MSOs are almost equivalent to that of FRⅡ sources, indicating that the jet power of CSOs and MSOs　is favorably comparable to that of FRⅡsources. The hot spot pressure and radius show simple power-　law changes as expected from the dynamical evolution model of the hotspot. This is a supporting　evidence for evolutional sequence from CSOs to MSOs to FRⅡ sources．<br />　　Overall results strongly argue that CSOs are young extragalactic radio sources that are potentially　able to evolve into FRⅡ sources through MSOs.","subitem_description_type":"Other"}]},"item_1_description_7":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"総研大甲第1034号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"物理科学研究科"}]},"item_1_select_9":{"attribute_name":"専攻","attribute_value_mlt":[{"subitem_select_item":"09 天文科学専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2006"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"NAGAI, Hiroshi","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1034_要旨.pdf","filesize":[{"value":"305.6 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨","url":"https://ir.soken.ac.jp/record/430/files/甲1034_要旨.pdf"},"version_id":"568607ac-4a80-481c-8580-03533df69a1d"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1034_本文.pdf","filesize":[{"value":"20.8 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文","url":"https://ir.soken.ac.jp/record/430/files/甲1034_本文.pdf"},"version_id":"c650dac8-87fa-4cdf-a8cd-4097a39d7e43"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Kinematic-and Synchrotron-Aging  Studies for Young Extragalactic Radio Sources","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Kinematic-and Synchrotron-Aging  Studies for Young Extragalactic Radio Sources"},{"subitem_title":"Kinematic-and Synchrotron-Aging  Studies for Young Extragalactic Radio Sources","subitem_title_language":"en"}]},"item_type_id":"1","owner":"1","path":["11"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-02-22"},"publish_date":"2010-02-22","publish_status":"0","recid":"430","relation_version_is_last":true,"title":["Kinematic-and Synchrotron-Aging  Studies for Young Extragalactic Radio Sources"],"weko_creator_id":"1","weko_shared_id":1},"updated":"2023-06-20T16:02:15.211517+00:00"}