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Cosmic Evolution of FRI and FRII Sources out to Z=2.5

ASTRONOMY & ASTROPHYSICS(2024)

Leiden Univ | Univ Edinburgh | Open Univ | Univ Durham | INAF IAPS

Cited 0|Views15
Abstract
Radio-loud active galactic nuclei (RLAGN) play an important role in the evolution of galaxies through the effects on their environment. The two major morphological classes are core-bright (FRI) and edge-bright (FRII) sources. With the LOw-Frequency ARray (LOFAR) we compare the FRI and FRII evolution down to lower flux densities and with larger samples than before with the aim to examine the cosmic space density evolution for FRIs and FRIIs by analyzing their space density evolution between L_150 10^24.5 W/Hz and L_150 10^28.5 W/Hz and up to z=2.5. We construct radio luminosity functions (RLFs) from FRI and FRII catalogues based on recent data from LOFAR at 150MHz to study the space densities as a function of radio luminosity and redshift. To partly correct for selection biases and completeness, we simulate how sources appear at a range of redshifts. We report a space density enhancement from low to high redshift for FRI and FRII sources brighter than L_150 10^27 W/Hz. This is possibly related to the higher gas availability in the earlier denser universe. The constant FRI/FRII space density ratio evolution as a function of radio luminosity and redshift in our results suggests that the jet-disruption of FRIs might be primarily caused by events occurring on scales within the host galaxy, rather than being driven by changes in the overall large-scale environment. Remaining selection biases in our results also highlight the need to resolve more sources at angular scales below 40 arcsec and therefore strengthens the motivation for the further development and automation of the calibration and imaging pipeline of LOFAR data to produce images at sub-arcsecond resolution.
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galaxies: active,galaxies: evolution,galaxies: statistics,radio continuum: galaxies
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要点】:通过LOFAR观测数据,研究FRI和FRII源在红移至z=2.5的宇宙空间密度演化,发现高红移下亮于L_150 10^27 W/Hz的FRI和FRII源空间密度增加,并推测与早期宇宙中气体可用性更高有关。

方法】:利用LOFAR在150MHz的观测数据构建FRI和FRII的射电亮度函数(RLFs),并通过模拟不同红移下的源外观,部分校正选择偏差和完整性。

实验】:通过分析LOFAR数据,构建射电亮度函数,研究FRI和FRII的空间密度随红移和射电亮度的变化,发现FRI/FRII空间密度比在射电亮度和红移上的恒定性,指出FRI的喷流中断可能主要是由宿主星系内的事件引起的。实验使用的数据集为LOFAR在150MHz的观测数据。