GOODS天區次毫米波星系的聚集

Abstract

次毫米波星系為一群於紅外波段非常明亮的星系。因為大氣層吸收帶影響，地面能觀測的窗口在遠紅外波段部分為次毫米波段(10−6 − 10−3 m)，主要受到水氣吸收影響。星系演化圖像中，恆星形成過程會伴隨劇烈的紅外波段輻射，故次毫米波星系是瞭解星系演化極為重要的一環。我們使用來自 GOODS 天區 SCUBA-2 次毫米波星系的觀測數據，結合使用 Ks 紅外波段非活躍星系的數據，對兩者做相關性研究，由此推導出星系的空間聚集半徑 r0 及星系可能存在的暗物質暈 Mhalo 大小。本研究發現次毫米波星系的聚集強度比文獻所提及的較低。

Submillimeter galaxies (SMGs) are high-redshift galaxies (z = 1 − 4) with very bright flux densities in the submillimeter waveband. To study their nature and their role in the galaxies evolution history, we present an angular clustering measurement of SMGs in the GOODS-North and GOODS-South. We make a 2.0 mJy and 0.5 mJy cut on 850 µm flux density and noise. The total available SMG sources are 141, with 75 in North and 66 in South. Due to the large uncertainties induced from small size target autocorrelation, we conduct a cross-correlation between target and tracer with larger size to effectively reduce the uncertainties. We use ∼ 2500 Ks-selected normal galaxies from deep infrared observations in each field. We derive the clustering lengths and linear galaxy biases of both populations, which lead to the estimation of the SMG clustering length of r0 ∼ 4−5 h−1 Mpc. We find that SMGs do not cluster strongly as reported in previous studies, occupying dark matter halo mass of Mhalo ∼ 1012 M⊙.