Properties of Barred Spiral Galaxies

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/74049

Title:	Properties of Barred Spiral Galaxies
Authors:	王吟方;Wang, Ying-Fang
Contributors:	天文研究所
Keywords:	棒狀螺旋星系;恆星生成率;barred spiral galaxies;star formation rate
Date:	2017-07-20
Issue Date:	2017-10-27 13:06:16 (UTC+8)
Publisher:	國立中央大學
Abstract:	我們研究了棒狀螺旋星系與螺旋星系的特性。我們從史隆數位化巡天所釋出的第十二版的資料（SDSS DR12）中選出了355159個紅移在0.001到0.1之間的星系。星系動物園 (Galaxy Zoo 2)是一個讓公眾可以上網分類星系型態的一個計畫。如果有一半的人認為這個星系是棒狀螺旋星系，我們就把這個星系當作是棒狀螺旋星系。如果有一半的人認為這個星系是螺旋星系但不具有棒狀結構，我們就把它當成螺旋星系。為了不要讓環境影響我們的研究，所以我們只選在一百萬秒差距內擁有少於100個鄰居的星系。我們的結論顯示，無論在哪個紅移及星等範圍，棒狀螺旋星系會比螺旋星系擁有更多的鄰居，所以我們推論棒狀結構的形成可能源自於周圍鄰居的重力作用影響。我們的另一個結果是跟活躍星系核有關，不論鄰居多寡，我們發現棒狀螺旋星系會比螺旋星系有更高比例的活躍星系核。而螺旋星系則會隨著鄰居數越多，有較高的活躍星系核比例。這個結果顯示棒狀結構可能可以觸發活躍星系核，而螺旋星系會因為星系的交互作用而產生活躍星系核。我們還有一個結果是關於星系的恆星生成率。我們發現棒狀螺旋比螺旋星系有更集中的恆星生成率且棒狀螺旋星系有較高的恆星生成率。;We studied the properties of barred spiral galaxies and non-barred spiral galaxies. We selected 355159 galaxies from the Sloan Digital Sky Survey Data Release 12 (DR12) with redshifts between 0.001 and 0.1. We considered a galaxy as a barred spiral galaxy if the source has a barred spiral vote fraction greater than 0.5 in the Galaxy Zoo 2; To avoid influence caused by rich galaxy clusters, we only choose galaxies with less than 100 neighbors galaxies within 1 Mpc. Our results show that there is a positive correlation between the ratios of barred spirals to non-barred spiral galaxies and the numbers of their neighbor galaxies independent of their redshifts indicating that bar formation may be caused by tidal forces or gravitational forces. Our results also show that there are higher fractions of AGN-host galaxies in the bar-spiral galaxies than in the non-barred ones independent of their companions. These results indicate that bars might play a important role in triggering AGNs. On the other hand, the fractions of AGN-host galaxies in non-barred spiral galaxies highly depend on their companions, suggesting that the AGNs in the non-barred spirals might be triggered by galaxy interactions. Our results also show that the star formation rates (SFRs) of the whole galaxy of barred spiral galaxies and non-barred spiral galaxies are different, and the SFR of barred spiral are more concentrated than non-barred spiral galaxies.
Appears in Collections:	[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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