藉由 SDSS-IV MaNGA 觀測數據研究矮星系中的暗物質含量;Dark Matter Content of Dwarf Galaxies in SDSS-IV MaNGA

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/89213

Title:	藉由 SDSS-IV MaNGA 觀測數據研究矮星系中的暗物質含量;Dark Matter Content of Dwarf Galaxies in SDSS-IV MaNGA
Authors:	吳偉靜;Wu, Weijing
Contributors:	天文研究所
Keywords:	MaNGA;暗物質;矮星系;旋轉曲線;MaNGA;dark matter;dwarf galaxies;rotation curve
Date:	2022-09-19
Issue Date:	2022-10-04 11:01:29 (UTC+8)
Publisher:	國立中央大學
Abstract:	我們藉由 SDSS-IV MaNGA 觀測數據，研究矮星系中的暗物質含量。我們把目標星系分為早型星系和晚型星系、平衡系統和未平衡系統，其中大部份的晚型星系為平衡系統。我們利用 Ha 和恆星速度場，分別推導星系的旋轉曲線，從而估算星系質量。我們發現大部份的目標星系的質量遠大於其重子質量，以及一個暗物質含量很高的平衡星型星系和三個暗物質含量很少的未平衡晚型星系。此外，我們比照觀測所得的暗物質密度分佈和三個暗物質模型（NFW、模糊暗物質、偽等溫模型）的預測，發現一些星系的暗物質密度分佈和多個模型的預測吻合，整體而言無法區分這三種模型。最後，我們對比從和恆星速度場分別得出的分析結果，發現兩者並不完全一致，從速度場得出的結果較為離散。這些恆星形成氣體可能剛被星系吸積，尚未與星系自身的重力場達到平衡。 ;In this study, we examine the dark matter content of dwarf galaxies from SDSS-IV MaNGA database. We classified the galaxies into late-type galaxies (LTGs) and early-type galaxies (ETGs), equilibrium and non-equilibrium. There are more equilibrium galaxies in LTGs. We estimate rotation curves from Ha and stellar velocity fields respectively, and use them to derive dynamical mass. The majority of targets have dynamical mass much greater than baryonic mass, with dark matter constituting at least 70% of dynamical mass. One equilibrium ETG that is very dark-matter-dominated and three non-equilibrium LTGs have little or no dark matter. We also fit the observed dark matter density profiles to three dark matter models: Navarro-Frenk-White (NFW), fuzzy dark matter, and pseudo-isothermal profiles. Some galaxies can be fitted with multiple models. It is difficult to distinguish which model fits better. Besides, we compare the analysis results from the Ha and stellar velocity maps. The two results of the same galaxy are not always consistent with each other, and the results from the Ha data is more scattered. This suggests that the star-forming gas may have an external origin, and has not yet reached equilibrium with the galaxy.
Appears in Collections:	[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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