Spitzer Observations of Massive, Red Galaxies at High Redshift-猫眼课题宝

DOI：

10.1086/499915

发表时间：

2005-11

期刊：

The Astrophysical Journal

影响因子：

通讯作者：

中科院分区：

其他

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作者：

C. Papovich;L. Moustakas;M. Dickinson;E. Floc’h;G. Rieke;E. Daddi;D. Alexander;F. Bauer;W. Brandt;T. Dahlén;E. Egami;P. Eisenhardt;D. Elbaz;H. Ferguson;M. Giavalisco;R. Lucas;B. Mobasher;P. Pérez-González;A. Stutz;M. Rieke;H. Obs.;Spitzer Fellow;Jpl;Noao;O. Paris;Ioa;Chandra Fellow;C. Univ.;Penn State;Stsci;S. Univ.;C. Saclay;Ssc

我们利用HST光学成像、地基近红外成像和斯皮策3-24 μm观测研究了z ~ 1-3.5的大质量星系。从130 arcmin ~ 2 GOODS-S场中的K_s选择星系中，我们识别出153个（J-K_s）Vega ≥ 2.3的遥远红星系（DRG）。对于1011 M以上且z ≤ 3的被动演化星系，该样本的恒星质量近似完整。大约有一半的DRG天体的光学和近红外静止框架光主要由演化的恒星和正在形成的星星组成（zmed ~ 2.5），而其他的则是由严重变红（A1600等4-6等）的恒星爆发（zmed ~ 1.7）控制的星系。极少数DRG（± 10%）没有当前星星形成的迹象。z ~ 1.5-3的DRG，恒星质量≥1011 M，具有特定的星星形成速率（每单位质量的SFR），包括0.2到10 Gyr-1的再辐射远红外辐射。基于X射线光度和静止帧近红外颜色，大约四分之一的DRG包含活动星系核，这意味着超大质量黑洞的生长与大质量星系的形成相一致。在1.5 ≤ z ≤ 3时，M ≥ 1011 M的DRG具有与所有星系的整体值相当的积分比SFR。与此相反，在z ~ 0.3-0.75，M ≥ 1011 M的星系的综合比SFR小于整体值，比大质量DRG低一个数量级以上。在z = 1处，较低质量的星系在整个宇宙质量组合中占主导地位。这表明，大质量星系中的大部分星星形成发生在早期宇宙纪元，并在z ~ 1.5时基本完成。在这些星系中进一步的质量组装发生在低比SFR。

We study massive galaxies at z ~ 1-3.5 using HST optical imaging, ground-based near-IR imaging, and Spitzer observations at 3-24 μm. From Ks-selected galaxies in the ≃130 arcmin2 GOODS-S field, we identify 153 distant red galaxies (DRGs) with (J - Ks)Vega ≥ 2.3. This sample is approximately complete in stellar mass for passively evolving galaxies above 1011 M☉ and z ≤ 3. Roughly half of the DRGs are objects whose optical and near-IR rest-frame light is dominated by evolved stars combined with ongoing star formation (at zmed ~ 2.5), and the others are galaxies whose light is dominated by heavily reddened (A1600 ≳ 4-6 mag) starbursts (at zmed ~ 1.7). Very few DRGs (≲10%) have no indication of current star formation. DRGs at z ~ 1.5-3 with stellar masses ≥1011 M☉ have specific star formation rates (SFRs per unit mass) including the reradiated far-IR emission that range from 0.2 to 10 Gyr-1. Based on the X-ray luminosities and rest-frame near-IR colors, roughly one-quarter of the DRGs contain AGNs, implying that the growth of supermassive black holes coincides with the formation of massive galaxies. At 1.5 ≤ z ≤ 3, the DRGs with M ≥ 1011 M☉ have an integrated specific SFR comparable to the global value of all galaxies. In contrast, galaxies at z ~ 0.3-0.75 with M ≥ 1011 M☉ have an integrated specific SFR less than the global value and more than an order of magnitude lower than that for massive DRGs. At z ≲ 1, lower mass galaxies dominate the overall cosmic mass assembly. This suggests that the bulk of star formation in massive galaxies occurs at early cosmic epochs and is largely complete by z ~ 1.5. Further mass assembly in these galaxies takes place with low specific SFRs.

Spitzer Observations of Massive, Red Galaxies at High Redshift

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