Merging Galaxies in the SWIRE Fields Merging Galaxies in the SWIRE Fields

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/43730

Title:	Merging Galaxies in the SWIRE Fields Merging Galaxies in the SWIRE Fields
Authors:	黃美綾;Mei-Ling Huang
Contributors:	天文研究所
Keywords:	合併星系;merging galaxies
Date:	2010-07-14
Issue Date:	2010-12-08 14:17:27 (UTC+8)
Publisher:	國立中央大學
Abstract:	我們分析了400多個合併星系在紅外線與可見光波段的性質，以了解其恆星生成率的特色。我們的樣本來自超過一萬五千個合併星系的目錄。這個目錄裡的合併星系由加法夏天文台(CFHT)所觀測，經過程式的自動篩選和肉眼的人工判斷而被認定為合併星系；紅外波段的資料來自史匹哲太空望遠鏡的觀測。我們的分析結果顯示，在低紅移時，由兩個橢圓星系組成的合併星系的數量比先前的研究來得少。雖然大多數的合併星系都有被激發的恆星生成率，擁有極大恆星生成率的合併星系卻很少。另外，恆星生成率和合併星系的成員星系間的距離、星等差呈現負相關。最後我們發現，相較於場環境，氣體少的合併星系的比例在星系團裡比較高，而且氣體多的合併星系的恆星生成率在星系團裡比較低。 We present the infrared and optical properties of more than 400 merging galaxies to explore their features of star formation efficiency. The ~400 merging systems are from a catalog of 15k morphologically identified merging galaxies observed with the Canada-France-Hawaii Telescope, and the IR data are from the Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE). Our analyses show that the fraction of mergers of two early-type galaxies at low redshifts is much smaller than those found in previous studies. Although most merging systems do show enhanced star formation activity, merging systems with extremely high star formation rates (SFR) are rare. However, there is an anti-correlation between the specific SFR (SSFR) and the separation of the merging galaxies. In addition, the SSFR of merging galaxies also decreases when the magnitude difference between two member galaxies becomes large. Finally, we find a higher fraction of gas-poor mergers in galaxy clusters and the SSFR of gas-rich mergers is reduced in cluster environment.
Appears in Collections:	[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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