Near-infrared K-band imaging of a sample of ultra-steep-spectrum radio sources selected at 74 MHz
Near-infrared K-band imaging of a sample of ultra-steep-spectrum radio sources selected at 74 MHz
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在 74 MHz 处选择的超陡频谱无线电源样本的近红外 K 波段成像
DOI：
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发表时间：
2004
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通讯作者：
Naval Research Lab. Leiden
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作者：
Matt J.Jarvis;Maria J.Cruz;Aaron S.Cohen;H. Rottgering;Namir E.Kassim Oxford;Naval Research Lab. Leiden
在本文中，我们展示了在 74 MHz 下选择的超陡频谱 (USS) 无线电源样本的近红外 K 波段成像。低频和USS的双重选择标准意味着我们应该对最高红移（z > 5）射电星系敏感。我们已经获得了 26 个样本中所有天体的 K 波段星等，并讨论了每个天体的属性。
与 Willott 等人的 7CRS 等完全未过滤的样本相比，该样本存在明显的偏向较弱的星等，因此红移较高，这意味着陡峭频谱技术在 74 MHz 下仍然可行。然而，还有更亮的（K 15 角秒（6C* 的角尺寸截止））。
我们发现，当对 74 MHz 样本应用类似的角度大小滤波时，在 74 MHz 下选择的样本的 K 波段幅度分布在统计上与 6C* 样本无法区分。
In this paper we present near-infrared K-band imaging of a sample of ultra-steep-spectrum (USS) radio sources selected at 74 MHz. The dual selection criteria of low frequency and USS mean that we should be sensitive to the highest-redshift (z > 5) radio galaxies. We have obtained K-band magnitudes for all of the objects in our sample of 26 and discuss the properties of each.
There is a pronounced bias in this sample towards fainter magnitudes and thus higher redshifts when compared to complete unfiltered samples such as the 7CRS of Willott et al., implying that the steep-spectrum technique is still viable at 74 MHz. However, there are more bright (K 15 arcsec (the angular size cut-off of 6C*).
We find that the distribution of K-band magnitudes from a sample selected at 74 MHz is statistically indistinguishable from the 6C* sample, when similar angular size filtering is applied to the 74-MHz sample.