重訪雙顏色選樣：NUV-r-J選樣下寧靜星系的次毫米波與活躍星系核性質

在這個研究中，我們重新探訪大量應用於寧靜星系(quiescent galaxy)的選樣方法，N U V−r−J雙顏色選樣(color-color selection)。灰塵吸收與年老恆星有相似的發光顏色，從高紅移星系選出候選寧靜星系時，有可能誤選入了瀰塵恆星形成星系(dusty star-forming galaxy)。因此，我們在COSMOS天區內選取了17811個寧靜星系，使用S2COSMOS、STUDIES等大型計畫的JCMT SCUBA-2 450和850微米波段資料，檢驗他們的寧靜性質。我們使用交叉匹配與疊加方法，結果顯示候選寧靜星系中約有10%的誤選樣本。我們也進行模擬運算，檢驗SCUBA-2次毫米波源與候選寧靜星系的空間關係。我們的結果在7′′的尺度下顯示了叢集效應。我們更進一步發現我們的資料中有寧靜星系與無線電波活躍星系核的相關性，這個發現給予我們恆星形成抑制機制的觀點。

關鍵字

星系: 演化；星系: 恆星形成；星系: 統計；星系: 高紅移；次毫米波: 星系

並列摘要

In our study, we revisit theN U V−r−Jcolor-color selection, which is widely applied for selecting quiescent galaxies (QGs). The selected QG candidates at high red-shift may be contaminated by dusty star-forming galaxies because of the degeneracy of old stars and dust absorption. Therefore, we selected 17811 QGs in the COSMOS field and examined their quiescence using JCMT SCUBA-2 450 and 850μm sources from theS2COSMOS and STUDIES Large Programs. We performed cross-matching and stackinganalysis, and the results suggest a∼10% contamination rate with our selection method. We also conducted simulations and examined the spatial correlation between SCUBA-2submillimeter sources and QG candidates. Our results show a clustering signal on a scale of 7′′. In addition, we found a correlation between QGs and radio AGNs in our sample, which provides us with some insights into the quenching mechanism in QGs.