摘要
次毫米波星系是一種位於高紅移的星系，它的大質量和非常高的恆星形成率，一般相信是由星系合併所產生的結果。本篇論文主要研究次毫米波星系的性質以及它們在大尺度結構中所扮演的角色。 研究方法是計算次毫米波星系周圍的可見光星系密度，以及藉由關聯性方程式這種統計方法來分析次毫米波星系與萊曼α發射星系的關係。主要研究的範圍是COSMOS和ECDF-S天區。在ECDF-S天區中，LABOCA和AzTEC儀器所觀測到的次毫米波星系有紅位移的估計，可以有效減少天空中投影的效應。我們取半徑為1-2個百萬秒差距計算次毫米波星系周圍的星系密度，結果顯示在紅移2.5和3.5的地方有些微的訊號，不過還是需要注意紅移的誤差造成的不確定性。我們更進一步使用B、z 、K三個濾鏡選取出BzK星系，它們可以區分出星系是否還有恆星生成。我們發現在一個百萬秒差距內，低恆星生成率的BzK星系與次毫米星系有較高的關聯性。另一方面，使用關聯性方程式分析次毫米波星系與萊曼α發射星系，結果沒有顯示任何訊號，亦即兩種星係可能沒有空間上的關連性。最後我們討論了次毫米波星系所在的大尺度結構的性質以及次毫米波星系與其他高紅移星系之間的交互關係。
並列摘要
To study the environment of high-redshift star-forming galaxy — submillime- ter galaxies (SMGs) — and their role during large-scale structure formation, we have estimated the galaxy number density fluctuations around SMGs, and analyzed their cross correlation functions with lyman alpha emitters (LAEs), and optically-selected galaxies with photometric redshift in the COSMOS and ECDFS fields. We first measured the galaxy density around SMGs based on SMGs with photometric redshift zSMG compiled from data obtained by LABOCA and AzTEC in the ECDFS field. The number density of surrounding galaxies within projected radius of 1–2 Mpc and zSMG ± 0.1 suggests a marginal signal of excess galaxy count at z ∼ 2.5 and ∼ 3.5, although the uncertainty of redshift estimate is still large. We have further investigated the density of passive and starforming BzK galaxies at similar redshift around SMGs and find that BzKs have overdensity around LABOCA-SMGs at radius smaller than 1 Mpc, espe- cially passive BzKs. On the other hand, our second task, the cross correlation functions between SMGs and LAEs, detects no correlation signal between the two populations, even after the exclusion of the SMGs with redshift significantly far from that of LAEs. Finally we discuss the property of the large scale struc- ture where SMGs are located and the interconnection between SMGs and other high-redshift galaxy populations.
參考文獻
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延伸閱讀
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