{"created":"2021-03-01T06:16:13.048923+00:00","id":9449,"links":{},"metadata":{"_buckets":{"deposit":"2d345c6b-1753-4667-bdb1-4e440529f7e0"},"_deposit":{"id":"9449","owners":[],"pid":{"revision_id":0,"type":"depid","value":"9449"},"status":"published"},"_oai":{"id":"oai:nagoya.repo.nii.ac.jp:00009449","sets":["336:635:636"]},"author_link":["26952","26953"],"item_12_alternative_title_19":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"重力マイクロレンズを用いた銀河構造の研究","subitem_alternative_title_language":"ja"}]},"item_12_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2002-03-25","bibliographicIssueDateType":"Issued"}}]},"item_12_date_granted_64":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2002-03-25"}]},"item_12_degree_grantor_62":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"名古屋大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Nagoya University"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"13901","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_12_degree_name_61":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士(理学)","subitem_degreename_language":"ja"}]},"item_12_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"The use of the Gravitational Microlensing effect has been established as a new tool to study Galactic structure by detecting the massive objects, e.g., “Assive Compact Halo Object (MACHO)” in the halo and also stars in the Galactic bulge and disk. We have proposed two new methods in this paper to constrain the location of gravitational microlensing objects towards the Large Magellanic Cloud (LMC) using EAGLE (Extremely Amplified Gravitational LEnsing) events.  This EAGLE event is the microlensing event in which the source star is fainter than the observational limiting magnitude.  We have estimated the event rate of EAGLEs and found that is the same as or higher than that of ordinary microlensing events which have been found until now.  We have also found that the fraction of transit EAGLE events, in which the proper motion of the lens can be estimated, is sufficiently large to detect.  It turns out to be between 4～80% depending on the lens location. Then we can discriminate the lens in the halo from that in the LMC itself.  We show that it is possible to determine whether lens objects are located in the Galactic heavy thick disk or in the Galactic halo, with ground-based observation.  The possibility to observe the parallax effect in EAGLE events is higher than normal events, in which the “reduced” transverse velocity of the lens could be obtained.  Then we can distinguish whether the lens is in the halo or the thick disk. To check whether EAGLE events could actually be detected or not, we analyzed the data of the Galactic Bulge (GB) taken by the MOA group.  The analysis of the GB data is a good demonstration, because our observation towards the GB is aimed to detect such EAGLE type events in which the probability to find the Extrasolar Planets is very high.We analyzed the MOA GB data during the 2000 season with use of the Difference Image Analysis (DIA) method and found 28 candidates of the microlensing event in the 12GB field corresponding to 16deg^2 which contain 250 million stars down to I～23.  The DIA improved the quality of photometry, and enable us to detect more events with faint source stars such as EAGLE events especially in our high frequent observations.  DIA also gives us a non-biased light curve, i.e. event parameters, even in the case that the source star is blended. We have done a Monte Carlo simulation to estimate the microlensing event detection efficiencies of our observation and analysis.  We made the I-band extinction map for our 14GB fields in order to know the real baseline magnitude in each field.  From these efficiencies and the timescales of observed events, an optical depth towards the GB was obtained for events with the timescales within 0.3< t_E<150 days as τ\\bigin 150 \\ 0.3 \\end = 2.62\\bigin+0.72\\-0.56\\end ×10^{-6}.  With consideration of the disk-disk component, an optical depth for the bulge component was estimated to beτbulge = 3.40\\bigin+0.94\\-0.73\\end × 10^{-6}[0.77/(1-fdisk)], assuming a 23% stellar contribution from disk stars.  These observed optical depths are consistent with the previous observations by MACHO and OGLE groups.  These values are higher than those predicted by existing Galactic Models.  We presented the timescale distribution of the observed events, and found there are no significant small mass lenses such as brown dwarfs, in spite of our high detection efficiency for short timescale events down to t_E～0.3 days.  Furthermore, we found that more than half of all detected events are EAGLE type events as expected and 50% of all events have high magnification( A>10).  So if a similar observation could be carried out towards the LMC, we can constrain the location of the lensing objects towards the LMC by estimating the lens proper motion or reduced velocity.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_12_description_5":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_description":"名古屋大学博士学位論文 学位の種類:博士(理学) (課程) 学位授与年月日:平成14年3月25日","subitem_description_language":"ja","subitem_description_type":"Other"}]},"item_12_dissertation_number_65":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第5388号"}]},"item_12_identifier_60":{"attribute_name":"URI","attribute_value_mlt":[{"subitem_identifier_type":"HDL","subitem_identifier_uri":"http://hdl.handle.net/2237/11230"}]},"item_12_select_15":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_select_item":"publisher"}]},"item_12_text_14":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_text_value":"application/pdf"}]},"item_12_text_63":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2001"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"住, 貴宏","creatorNameLang":"ja"}],"nameIdentifiers":[{"nameIdentifier":"26952","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Sumi, Takahiro","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"26953","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2018-02-20"}],"displaytype":"detail","filename":"ko5388.pdf","filesize":[{"value":"15.9 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"ko5388.pdf","objectType":"fulltext","url":"https://nagoya.repo.nii.ac.jp/record/9449/files/ko5388.pdf"},"version_id":"ca5071c0-b954-4e37-946e-16146046775d"}]},"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":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"The study of the galactic structure by using gravitational microlensing","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"The study of the galactic structure by using gravitational microlensing","subitem_title_language":"en"}]},"item_type_id":"12","owner":"1","path":["636"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2009-03-03"},"publish_date":"2009-03-03","publish_status":"0","recid":"9449","relation_version_is_last":true,"title":["The study of the galactic structure by using gravitational microlensing"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-01-16T04:29:24.870547+00:00"}