High-redshift quasars at $z \geq 3$ -- III. Parsec-scale jet properties from VLBI observations
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arXiv
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| Autores principales: | , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866910838925819904 |
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| author | Guo, Shaoguang An, Tao Liu, Yuanqi Liu, Chuanzeng Xu, Zhijun Sotnikova, Yulia Mufakharov, Timur Wang, Ailing |
| author_facet | Guo, Shaoguang An, Tao Liu, Yuanqi Liu, Chuanzeng Xu, Zhijun Sotnikova, Yulia Mufakharov, Timur Wang, Ailing |
| contents | High redshift active galactic nuclei (AGN) provide key insights into early supermassive black hole growth and cosmic evolution. This study investigates the parsec-scale properties of 86 radio-loud quasars at z $\geq$ 3 using very long baseline interferometry (VLBI) observations. Our results show predominantly compact core and core-jet morphologies, with 35\% unresolved cores, 59\% core-jet structures, and only 6\% core-double jet morphology. Brightness temperatures are generally lower than expected for highly radiative sources. The jet proper motions are surprisingly slow compared to lower-redshift samples. We observe a high fraction of young and/or confined peak-spectrum sources, providing insights into early AGN evolution in dense environments during early cosmic epochs. The observed trends may reflect genuine evolutionary changes in AGN structure over cosmic time, or selection effects favoring more compact sources at higher redshifts. These results stress the complexity of high-redshift radio-loud AGN populations and emphasize the need for multi-wavelength, high-resolution observations to fully characterize their properties and evolution through cosmic history. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_15527 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | High-redshift quasars at $z \geq 3$ -- III. Parsec-scale jet properties from VLBI observations Guo, Shaoguang An, Tao Liu, Yuanqi Liu, Chuanzeng Xu, Zhijun Sotnikova, Yulia Mufakharov, Timur Wang, Ailing High Energy Astrophysical Phenomena High redshift active galactic nuclei (AGN) provide key insights into early supermassive black hole growth and cosmic evolution. This study investigates the parsec-scale properties of 86 radio-loud quasars at z $\geq$ 3 using very long baseline interferometry (VLBI) observations. Our results show predominantly compact core and core-jet morphologies, with 35\% unresolved cores, 59\% core-jet structures, and only 6\% core-double jet morphology. Brightness temperatures are generally lower than expected for highly radiative sources. The jet proper motions are surprisingly slow compared to lower-redshift samples. We observe a high fraction of young and/or confined peak-spectrum sources, providing insights into early AGN evolution in dense environments during early cosmic epochs. The observed trends may reflect genuine evolutionary changes in AGN structure over cosmic time, or selection effects favoring more compact sources at higher redshifts. These results stress the complexity of high-redshift radio-loud AGN populations and emphasize the need for multi-wavelength, high-resolution observations to fully characterize their properties and evolution through cosmic history. |
| title | High-redshift quasars at $z \geq 3$ -- III. Parsec-scale jet properties from VLBI observations |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2502.15527 |