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arXiv 0802.2694astro-ph
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高红移红外/射电相关研究

Exploring the infrared/radio correlation at high redshift

Edo Ibar, Michele Cirasuolo, Rob Ivison, Philip Best, Ian Smail, Andy Biggs, Chris Simpson, Jim Dunlop, Omar Almaini, Ross McLure, Sebastien Foucaud, Steve Rawlings

摘要:

我们已经分析了24 μ m的无线电选定的样品在斯巴鲁XMM/牛顿深场的属性,以探讨在高红移的FIR/无线电关系的行为。在统计上,相关性用q24来描述,q24是分别在24 μ m和1.4GHz处观测到的通量密度之间的比率。使用24微米的数据结果在相当多的分散在相关性比以前的工作使用的数据在60- 70微米。然而,我们确实观察到了稳定的相关性作为红移的函数,直到z~3.5,这表明它的有效性可以追溯到原始时代。基于300 uJy < S(1.4GHz)< 3.2mJy和24 um探测的源,我们发现观测的q24 = 0.30 +/- 0.56,k校正的射电样本的q24 = 0.71 +/- 0.47。一个合适的K-校正M82样中红外模板表明没有极端的硅酸盐吸收在我们的大部分无线电样品。利用q24中的阈值来识别射电过剩源,我们已经能够在微弱(<1 mJy)的射电通量密度下观测到从射电强活动星系核到恒星形成星系和射电静活动星系核的转变。我们的研究结果与先前的研究结果基本一致,这些研究表明,在> 1 mJy时,活动星系核的射电噪声占主导地位。预期无线电过量群体的休息帧U-B颜色的分布比遵循相关性的分布更红。因此,这是一个有希望的方式来选择模糊的2型活动星系核,具有无线电响亮的性质,错过了深X射线观测。需要对这些来源进行光谱跟踪,以充分测试这种方法。

英文摘要:

We have analysed the 24um properties of a radio-selected sample in the Subaru-XMM/Newton Deep Field in order to explore the behaviour of the FIR/radio relation at high redshifts. Statistically, the correlation is described by q24, the ratio between the observed flux densities at 24um and 1.4GHz, respectively. Using 24um data results in considerably more scatter in the correlation than previous work using data at 60-70um. Nevertheless, we do observe a steady correlation as a function of redshift, up to z~3.5, suggesting its validity back to primeval times. We find q24 = 0.30 +/- 0.56 for the observed and q24 = 0.71 +/- 0.47 for the k-corrected radio sample, based on sources with 300uJy < S(1.4GHz) < 3.2mJy and 24um detections. A suitable k-correction given by a M82-like mid-IR template suggests no extreme silicate absorption in the bulk of our radio sample. Using thresholds in q24 to identify radio-excess sources, we have been able to characterise the transition from radio-loud AGN to star-forming galaxies and radio-quiet AGN at faint (<1mJy) radio flux densities. Our results are in broad agreement with previous studies which show a dominant radio-loud AGN population at >1mJy. The rest-frame U-B colours of the expected radio-excess population have redder distribution than those that follow the correlation. This is therefore a promising way to select obscured Type-2 AGN, with a radio loud nature, missed by deep X-ray observations. Spectroscopic follow-up of these sources is required to fully test this method.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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