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arXiv 1012.5085astro-ph.CO
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HerMES:SPIRE/来自无线电选择的AGN的亚毫米发射

HerMES: SPIRE/Sub-millimetre Emission from Radio Selected AGN

N. Seymour, M. Symeonidis, M. Page, the HerMES Consortium

摘要:

本文研究了河外斯皮策首视巡天中1.4GHz强射电源的静止帧远红外辐射,其亮度密度为25<=log(L_1.4/WHz^-1)<=26.5。我们结合Herschel/SPIRE流量密度与Spitzer/IRAC和MIPS红外数据,获得这些射电源的总(8- 1000 μ m)红外光度。我们将我们的源分成中等的,0.4<z<0.9,和高的,1.2<z<3.0,红移子样本,我们使用斯皮策观测z<0.1 3CRR样本作为局部比较。通过与SKA模拟天空的数字比较,我们发现我们的中等红移样本是完整的,我们的高红移样本是14%完整的。我们将局域、中等和高红移样本的平均恒星形成率(SFR)的范围分别限定为3.4-4.2,18-41和80- 581 Msun/yr。因此,我们观察到平均SFR随着红移的增加而增加,我们可以将其参数化为~(1+z)^Q,其中Q=4.2+/-0.8。然而,我们没有观察到的平均SFR与无线电光度在中等或高红移箱的趋势。我们估计,在高红移样本中射电噪活动星系核对该时期总SFR密度的贡献为0.1- 0.5%。因此,如果所有明亮的星暴都是射电噪活动星系核的宿主,我们推断射电噪相位占空比为0.001-0.005。

英文摘要:

We examine the rest-frame far-infrared emission from powerful radio sources with 1.4GHz luminosity densities of 25<=log(L_1.4/WHz^-1)<=26.5 in the extragalactic Spitzer First Look Survey field. We combine Herschel/SPIRE flux densities with Spitzer/IRAC and MIPS infrared data to obtain total (8-1000um) infrared luminosities for these radio sources. We separate our sources into a moderate, 0.4<z<0.9, and a high, 1.2<z<3.0, redshift sub-sample and we use Spitzer observations of a z<0.1 3CRR sample as a local comparison. By comparison to numbers from the SKA Simulated Skies we find that our moderate redshift sample is complete and our high redshift sample is 14per cent complete. We constrain the ranges of mean star formation rates (SFRs) to be 3.4-4.2, 18-41 and 80-581Msun/yr for the local, moderate and high redshift samples respectively. Hence, we observe an increase in the mean SFR with increasing redshift which we can parameterise as ~(1+z)^Q, where Q=4.2+/-0.8. However we observe no trends of mean SFR with radio luminosity within the moderate or high redshift bins. We estimate that radio-loud AGN in the high redshift sample contribute 0.1-0.5per cent to the total SFR density at that epoch. Hence, if all luminous starbursts host radio-loud AGN we infer a radio-loud phase duty cycle of 0.001-0.005.

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