The VLA-COSMOS 3 GHz Large Project: Cosmic evolution of radio AGN and implications for radio- mode feedback since z 5
The VLA-COSMOS 3 GHz Large Project: Cosmic evolution of radio AGN and implications for radio- mode feedback since z 5
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DOI：
10.1051/0004-6361/201730685
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发表时间：
2017-05
影响因子：
6.5
通讯作者：
V. Smolčić;M. Novak;I. Delvecchio;L. Ceraj;M. Bondi;J. Delhaize;S. Marchesi;E. Murphy;E. Schinnerer;E. Vardoulaki;G. Zamorani
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作者：
V. Smolčić;M. Novak;I. Delvecchio;L. Ceraj;M. Bondi;J. Delhaize;S. Marchesi;E. Murphy;E. Schinnerer;E. Vardoulaki;G. Zamorani
基于1800多个红移至z5的射电活动星系核样本（典型恒星质量在3 ×（1010 - 1011）M ~ 2以内）和COSMOS场的3GHz射电数据，我们导出了z5范围内射电活动星系核的1.4GHz射电光度函数（L1.4GHz1022 - 1027 WHz ~（-1））。我们通过纯密度和纯光度演化的连续模型来约束这个种群的演化，并且我们找到了最佳拟合的参数化的Φ_（1 + z）（2.00 ± 0.18）-（0.60 ± 0.14）z，且L ≥（1 + z）（2.88 ± 0.82）-（0.84 ± 0.34）z，在z = 1.5时，星群的数量密度和光度密度发生了变化。我们将1.4 GHz的光度转换为动力学光度，考虑到所使用的标度关系的不确定性。我们由此导出了活动星系核提供的动力学光度密度的宇宙演化，并将此光度密度与半解析星系演化（SAGE）模型中假设的射电模式活动星系核反馈进行了比较，即，中心超大质量黑洞吸积光度的红移演化模型中采取的加热源，抵消了冷却，热晕气体的能量损失，从而限制了大质量星系的恒星质量进一步增长。我们发现，我们的无线电活动星系核施加的动力学光度可能是足够高，以平衡热气体的辐射冷却在每个宇宙时代以来的z 5。然而，尽管我们的研究结果支持射电模式活动星系核反馈作为大质量星系形成的宇宙学相关过程的想法，但在观测和半分析方法中仍然存在许多简化，需要在得出强有力的结论之前解决。
Based on a sample of over 1800 radio AGN at redshifts out to z 5, which have typical stellar masses within 3 × (1010 - 1011)M⊙, and 3 GHz radio data in the COSMOS field, we derived the 1.4 GHz radio luminosity functions for radio AGN (L1.4 GHz 1022 - 1027 W Hz-1) out to z 5. We constrained the evolution of this population via continuous models of pure density and pure luminosity evolutions, and we found best-fit parametrizations of Φ∗ ∝ (1 + z)(2.00 ± 0.18) - (0.60 ± 0.14)z, and L∗ ∝ (1 + z) (2.88 ± 0.82) - (0.84 ± 0.34)z, respectively, with a turnover in number and luminosity densities of the population at z ≈ 1.5. We converted 1.4 GHz luminosity to kinetic luminosity taking uncertainties of the scaling relation used into account. We thereby derived the cosmic evolution of the kinetic luminosity density provided by the AGN and compared this luminosity density to the radio-mode AGN feedback assumed in the Semi-Analytic Galaxy Evolution (SAGE) model, I.e., to the redshift evolution of the central supermassive black hole accretion luminosity taken in the model as the source of heating that offsets the energy losses of the cooling, hot halo gas, and thereby limits further stellar mass growth of massive galaxies. We find that the kinetic luminosity exerted by our radio AGN may be high enough to balance the radiative cooling of the hot gas at each cosmic epoch since z 5. However, although our findings support the idea of radio- mode AGN feedback as a cosmologically relevant process in massive galaxy formation, many simplifications in both the observational and semi-analytic approaches still remain and need to be resolved before robust conclusions can be reached.