{"_buckets": {"deposit": "96e97cc5-e736-475a-b7f0-d55d3cab693b"}, "_deposit": {"created_by": 1, "id": "431", "owners": [1], "pid": {"revision_id": 0, "type": "depid", "value": "431"}, "status": "published"}, "_oai": {"id": "oai:ir.soken.ac.jp:00000431", "sets": ["11"]}, "author_link": ["0", "0", "0"], "item_1_biblio_info_21": {"attribute_name": "書誌情報（ソート用）", "attribute_value_mlt": [{"bibliographicIssueDates": {"bibliographicIssueDate": "2007-03-23", "bibliographicIssueDateType": "Issued"}, "bibliographic_titles": [{}]}]}, "item_1_creator_2": {"attribute_name": "著者名", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "西川, 貴行"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_creator_3": {"attribute_name": "フリガナ", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "ニシカワ, タカユキ"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "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_1": {"attribute_name": "ID", "attribute_value_mlt": [{"subitem_description": "2007020", "subitem_description_type": "Other"}]}, "item_1_description_12": {"attribute_name": "要旨", "attribute_value_mlt": [{"subitem_description": "Optical jets and molecular bipolar outflows are two major manifestations\u003cbr /\u003eof outflowing activities associated with young stellar objects （YSOs）．It is\u003cbr /\u003enot clear how these two outflow activities are related with each other．One of\u003cbr /\u003ethe major scenarios is that a collimated jet seen in the optical－IR wavelength\u003cbr /\u003eentrains its ambient molecular material，a1lowing the molecular outflow to\u003cbr /\u003eoccur. In order for us to tackle this issue，it is crucial to understand how jets\u003cbr /\u003einteract with ambient material．\u003cbr /\u003e　In addition to the kinematics，the mass loss rate and mass momentum\u003cbr /\u003etransfer rate of are key parameters to investigate how the jet interacts\u003cbr /\u003ewith the ambient material.　However，the mass momentum is poorly known\u003cbr /\u003ebecause the hydrogen density is not easily derived， as is different from the\u003cbr /\u003eelectron density that is measured  from forbidden line emissions． If we assume\u003cbr /\u003ethat a jet is fully ionized, i.e. the electron density is nearly equal to the\u003cbr /\u003ehydrogen density，the mass momentum of the jet derived from its optical\u003cbr /\u003eemission lines is not sufficient to drive the molecular outflow associated with\u003cbr /\u003eit. In contrast，recent studies have suggested that jets are almost neutral，\u003cbr /\u003eindicating that a jet may have momentum sufficient to drive a molecular outflow．\u003cbr /\u003e　　In order to study the issues described above，we made slit-scan observa-\u003cbr /\u003etions of Hα and [NII] 6583 \u0026Aring; emission lines toward two bright jets，HH46/47\u003cbr /\u003eand the HL Tau jet，with Subaru Telescope. The large diameter of the tele-\u003cbr /\u003escope，together with the high spectral resolution of the spectrograph（High\u003cbr /\u003eDispersion Spectrograph，R =3.6×10\u003csup\u003e40\u003c/sup\u003e or \u0026Delta;v＝8km s\u003csup\u003e-1\u003c/sup\u003e）allowed us to\u003cbr /\u003estudy the kinematics of these jets in unprecedented detail．Furthermore，the\u003cbr /\u003eslit-scan technique with a long slit provided us with kinematic information\u003cbr /\u003eof the entire jets．\u003cbr /\u003e　　We found that，in both jets，the Hα emission traces both the main jet\u003cbr /\u003ecomponent（\u003ci\u003eV\u003c/i\u003e\u003csmall\u003eLSR\u003c/small\u003e＝－160～－180km s\u003csup\u003e-1\u003c/sup\u003e）and distinct lower velocity com-\u003cbr /\u003eponent （|\u003ci\u003eV\u003c/i\u003e\u003csmall\u003eLSR\u003c/small\u003e| \u0026le; 120km s\u003csup\u003e-1\u003c/sup\u003e）.　The [NII] emission, on the other hand，is\u003cbr /\u003eprimarily associated with the main jet component and is much faint or ab－\u003cbr /\u003esent in the lower velocity component. 　In the HH 46/47 jet，the velocities\u003cbr /\u003eof Hαand [NII] emission lines match well in their main jet components．\u003cbr /\u003eThe lower velocity components are associated with one-sided bow shocks\u003cbr /\u003eand with one of the Hα filaments that was previous identified with the\u003cbr /\u003e\u003ci\u003eHubble Space Telescope.\u003c/i\u003e　In　the　HL　Tau　jet，the　lower　velocity　component\u003cbr /\u003eis associated with indivisual knots, which is explained by the lower velocity\u003cbr /\u003eemmituion arising  in the laterals of bow shocks. While the main jet component\u003cbr /\u003eis associated with the ejecta, the lower velocity component is produced as a\u003cbr /\u003eresult of the interaction between the ejecta and the surrounding gas.\u003cbr /\u003e　　Observed Hα line profiles suggest that the shock velocities at the bow\u003cbr /\u003eshocks and the Hα filament with respect to the ambient gas are 60－80km s\u003csup\u003e-1\u003c/sup\u003e\u003cbr /\u003eand 120－130 km s\u003csup\u003e-1\u003c/sup\u003e for HH46/47 and HL Tau，respectively.　These are\u003cbr /\u003emarkedly smaller than the three dimensional（3－D）velocities of the jets（～300\u003cbr /\u003ekm s\u003csup\u003e-1\u003c/sup\u003e）．　　The discrepancy between the shock velocity and 3－D velocity is\u003cbr /\u003eexplained if the ambient gas moves outward by～200km s\u003csup\u003e-1.\u003c/sup\u003e.　The velocity\u003cbr /\u003eof the ambient gas measured in the HH46/47 jet is similar to those of HH\u003cbr /\u003e47A and 47D，giant bow shocks ahead of the observed region.\u003cbr /\u003e　　Through detailed analysis，we concluded that the outward motion of the\u003cbr /\u003e ambient gas is a result of prompt entrainment，i．e. a jet sweeps up ambient\u003cbr /\u003ematerial at its head by a large bow shock，but not of turbulent entrainment，\u003cbr /\u003ethe other entrainment mechanism proposed to date．Indeed，our high spec-\u003cbr /\u003etral resolution slit-scan observations of Hαshow that the main jet component\u003cbr /\u003ehas a uniform radial velocity of \u003ci\u003eV\u003c/i\u003e\u003csmall\u003eLSR\u003c/small\u003e＝－160km s\u003csup\u003e-1\u003c/sup\u003e（\u0026Delta;v＝10km s\u003csup\u003e-1\u003c/sup\u003e）and\u003cbr /\u003edid not show the presence of slow Hα components（ |\u003ci\u003eV\u003c/i\u003e\u003csmall\u003eLSR\u003c/small\u003e | \u0026le; 120km s-\u003csup\u003e1\u003c/sup\u003e）\u003cbr /\u003ealong the edges of the jets．Such slow Hα emission was reported in previous\u003cbr /\u003eobservations and was proposed to arise from turbulent boundary layers be-\u003cbr /\u003etween the main flow and the ambient gas.　Our results indicate that Hα and\u003cbr /\u003e[NII] originate from the main jet component（i．e. the ejecta），and also from\u003cbr /\u003ebow shocks and Hα filaments，but not from turbulent mixing layers.\u003cbr /\u003e　　 We also investigated the ionization fraction in the jets using the [NII] / Hα\u003cbr /\u003eflux ratio.　In the　case　of　HH46/47，the ratio is 0.2-0.5 in the main jet\u003cbr /\u003ecomponent and even higher in some other regions．Shock model calculations\u003cbr /\u003eshow that the ratio is sensitive to the ionization fraction of preshock gas if\u003cbr /\u003ethe shock velocity is less than l00 km s\u003csup\u003e-1\u003c/sup\u003e．　The　observed　high　ratio　for HH\u003cbr /\u003e46/47 is expected if its main jet component is considerably ionized，although\u003cbr /\u003eprevious observations proposed a much lower ionization fraction of\u0026le;0.2．\u003cbr /\u003eThe [NII] / Hαflux ratio is significantly smaller than 0.2  in the one-side bow\u003cbr /\u003eshocks and Hα filaments, indicating that the gas surrounding the ejecta is\u003cbr /\u003erather neutral．\u003cbr /\u003e　　For the HL Tau jet，the observed [NII] / Hα flux ratio markedly vary from\u003cbr /\u003eone region to another: 0.1-0.7 at the base of the jet，less than 0.1 in knot\u003cbr /\u003eA，～0.2 in knot B，～0.4 in knot C，and ～0.7 in knot D．Because the shock\u003cbr/\u003evelocities of the HL Tau jet exceed 100 km s\u003csup\u003e-1\u003c/sup\u003e in some regions，the ratio\u003cbr /\u003edoes not directly reflect the ionization fraction of preshock gas. At the knots\u003cbr /\u003eA－D，the [NII] / Hαflux ratio increases from ＜0.1 to 0.7 with distance from\u003cbr /\u003ethe source. This suggests that the preshock density decreases with distance\u003cbr /\u003efrom the source．The ratio at the lateral of the bow shocks is less than\u003cbr /\u003e～0.1，suggesting that the ambient medium is almost neutral．At the base\u003cbr /\u003eof the jet，the observed  [NII] / Hα flux ratio decreases from 0.7 to 0.1 as the\u003cbr /\u003edistance from the source increase. This suggests that the ionization fraction\u003cbr /\u003edecreases with distance as a result of radiative recombination．\u003cbr /\u003e　　We compared the [NII] / Hα ratio in the main jet components of the HH\u003cbr /\u003e46/47 jet and HL Tau jet. The ratio for the HH 46/47 jet is higher（0.2－0.5）\u003cbr /\u003ethan that for the HL Tau（\u0026le; 0.2），indicating high ionization fraction．Such\u003cbr /\u003ea difference suggests that the radiation from a nearby O star irradiates the\u003cbr /\u003eambient gas of the HH 46/47 system，which is located near the HII region\u003cbr /\u003eGum nebula，causing the high ionization fraction in the main jet component．\u003cbr /\u003eAnother possible interpretation is that radiative cooling by recombination is\u003cbr /\u003enot efficient in the HH 46/47 jet because of its low density，thus allowing the\u003cbr /\u003ehigh ionization fraction in the jet significantly away from the driving source．", "subitem_description_type": "Other"}]}, "item_1_description_18": {"attribute_name": "フォーマット", "attribute_value_mlt": [{"subitem_description": "application/pdf", "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1035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": "NISHIKAWA, Takayuki", "creatorNameLang": "en"}], "nameIdentifiers": [{"nameIdentifier": "0", "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": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 0, "filename": "甲1035_要旨.pdf", "filesize": [{"value": "382.0 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 382000.0, "url": {"label": "要旨・審査要旨", "url": "https://ir.soken.ac.jp/record/431/files/甲1035_要旨.pdf"}, "version_id": "241db0af-4181-4123-bb71-d6695aed5cd9"}, {"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 1, "filename": "甲1035_本文.pdf", "filesize": [{"value": "24.5 MB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 24500000.0, "url": {"label": "本文", "url": "https://ir.soken.ac.jp/record/431/files/甲1035_本文.pdf"}, "version_id": "147962ac-4eb9-4bbf-b037-149e7b57fa31"}]}, "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 Structure and Ionization of  Optical Jets Associated with Young Stellar Objects", "item_titles": {"attribute_name": "タイトル", "attribute_value_mlt": [{"subitem_title": "Kinematic Structure and Ionization of  Optical Jets Associated with Young Stellar Objects"}, {"subitem_title": "Kinematic Structure and Ionization of  Optical Jets Associated with Young Stellar Objects", "subitem_title_language": "en"}]}, "item_type_id": "1", "owner": "1", "path": ["11"], "permalink_uri": "https://ir.soken.ac.jp/records/431", "pubdate": {"attribute_name": "公開日", "attribute_value": "2010-02-22"}, "publish_date": "2010-02-22", "publish_status": "0", "recid": "431", "relation": {}, "relation_version_is_last": true, "title": ["Kinematic Structure and Ionization of  Optical Jets Associated with Young Stellar Objects"], "weko_shared_id": -1}