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arXiv 1303.3448astro-ph.CO
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光选类星体的AGN和星暴射电辐射

AGN and Starburst Radio Emission from Optically Selected QSOs

J. J. Condon, K. I. Kellermann, Amy E. Kimball, Zeljko Ivezic, R. A. Perley

摘要:

我们利用1.4GHz的NVSS研究了两个色选类星体样本中的射电源:一个是体积有限的1313个类星体样本,定义为M_i < -23,红移范围为0.2 < z < 0.45;另一个是星等有限的2471个类星体样本,定义为m_r < 18.5和1.8 < z < 2.5。大约有10%被探测到超过2.4 mJy NVSS目录限制,主要由AGN提供动力。低红移类星体的空间密度与(1+z)^[6]成正比地演化。在这两个红移范围内,强于2.4 mJy的类星体的通量密度分布和光度函数都是幂律的,没有特征表明有一种以上的射电源。将幂律定律外推到较低的光度预测剩下的类星体应该是非常无线电安静的,但它们不是。在NVSS图像上统计检测到大多数低和高红移样品的平均峰值通量密度S_p(mJy/beam)~ 0.3和0.05,分别对应于1.4 GHz光谱光度log[L(W/Hz)] ~ 22.7$和24.1。我们认为,在中等亮度(M_i ~ -23.4)的低红移类星体中,暗射电源的恒星形成速率约为20 M_sun/年,而在非常明亮(M_i ~ -27.5)的高红移类星体中,暗射电源的恒星形成速率约为500 M_sun/年。这种明亮的星暴[ log(L / L_sun)~ 11.2和12.6,分别]是符合“类星体模式”的吸积,其中冷气体流燃料AGN和星暴。

英文摘要:

We used the 1.4 GHz NVSS to study radio sources in two color-selected QSO samples: a volume-limited sample of 1313 QSOs defined by M_i < -23 in the redshift range 0.2 < z < 0.45 and a magnitude-limited sample of 2471 QSOs with m_r < 18.5 and 1.8 < z < 2.5. About 10% were detected above the 2.4 mJy NVSS catalog limit and are powered primarily by AGNs. The space density of the low-redshift QSOs evolves as rho proportional to (1+z)^6. In both redshift ranges the flux-density distributions and luminosity functions of QSOs stronger than 2.4 mJy are power laws, with no features to suggest more than one kind of radio source. Extrapolating the power laws to lower luminosities predicts the remaining QSOs should be extremely radio quiet, but they are not. Most were detected statistically on the NVSS images with median peak flux densities S_p(mJy/beam) ~ 0.3 and 0.05 in the low- and high-redshift samples, corresponding to 1.4 GHz spectral luminosities log[L(W/Hz)] ~ 22.7$ and 24.1, respectively. We suggest that the faint radio sources are powered by star formation at rates ~20 M_sun per year in the moderate luminosity (median M_i ~ -23.4) low-redshift QSOs and ~500 M_sun per year in the very luminous (M_i} ~ -27.5) high-redshift QSOs. Such luminous starbursts [ log(L / L_sun) ~ 11.2 and 12.6, respectively] are consistent with "quasar mode" accretion in which cold gas flows fuel both AGN and starburst.

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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