Revealing faint compact radio jets at redshifts above 5 with very long baseline interferometry

Fuente: arXiv
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Autores principales: Krezinger, Máté, Baldini, Giovanni, Giroletti, Marcello, Sbarrato, Tullia, Ghisellini, Gabriele, Giovannini, Gabriele, An, Tao, Gabányi, Krisztina É., Frey, Sándor
Formato: Preprint
Publicado: 2024
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author Krezinger, Máté
Baldini, Giovanni
Giroletti, Marcello
Sbarrato, Tullia
Ghisellini, Gabriele
Giovannini, Gabriele
An, Tao
Gabányi, Krisztina É.
Frey, Sándor
author_facet Krezinger, Máté
Baldini, Giovanni
Giroletti, Marcello
Sbarrato, Tullia
Ghisellini, Gabriele
Giovannini, Gabriele
An, Tao
Gabányi, Krisztina É.
Frey, Sándor
contents Over the past two decades, our knowledge of the high-redshift (z > 5) radio quasars has expanded, thanks to dedicated high-resolution very long baseline interferometry (VLBI) observations. Distant quasars provide unique information about the formation and evolution of the first galaxies and supermassive black holes in the Universe. Powerful relativistic jets are likely to have played an essential role in these processes. However, the sample of VLBI-observed radio quasars is still too small to allow meaningful statistical conclusions. We extend the list of the VLBI observed radio quasars to investigate how the source structure and physical parameters are related to radio loudness. We assembled a sample of 10 faint radio quasars located at 5 < z < 6 with their radio-loudness indices spanning between 0.9-76. We observed the selected targets with the European VLBI Network (EVN) at 1.7 GHz. The milliarcsecond-scale resolution of VLBI at this frequency allows us to probe the compact innermost parts of radio-emitting relativistic jets. In addition to the single-band VLBI observations, we collected single-dish and low-resolution radio interferometric data to investigate the spectral properties and variability of our sources. The detection rate of this high-redshift, low-flux-density sample is 90%, with only one target (J0306+1853) remaining undetected. The other 9 sources appear core-dominated and show a single, faint and compact radio core on this angular scale. The derived radio powers are typical of FRII radio galaxies and quasars. By extending our sample with other VLBI-detected z > 5 sources from the literature, we found that the core brightness temperatures and monochromatic radio powers tend to increase with radio loudness.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05192
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Revealing faint compact radio jets at redshifts above 5 with very long baseline interferometry
Krezinger, Máté
Baldini, Giovanni
Giroletti, Marcello
Sbarrato, Tullia
Ghisellini, Gabriele
Giovannini, Gabriele
An, Tao
Gabányi, Krisztina É.
Frey, Sándor
Astrophysics of Galaxies
Over the past two decades, our knowledge of the high-redshift (z > 5) radio quasars has expanded, thanks to dedicated high-resolution very long baseline interferometry (VLBI) observations. Distant quasars provide unique information about the formation and evolution of the first galaxies and supermassive black holes in the Universe. Powerful relativistic jets are likely to have played an essential role in these processes. However, the sample of VLBI-observed radio quasars is still too small to allow meaningful statistical conclusions. We extend the list of the VLBI observed radio quasars to investigate how the source structure and physical parameters are related to radio loudness. We assembled a sample of 10 faint radio quasars located at 5 < z < 6 with their radio-loudness indices spanning between 0.9-76. We observed the selected targets with the European VLBI Network (EVN) at 1.7 GHz. The milliarcsecond-scale resolution of VLBI at this frequency allows us to probe the compact innermost parts of radio-emitting relativistic jets. In addition to the single-band VLBI observations, we collected single-dish and low-resolution radio interferometric data to investigate the spectral properties and variability of our sources. The detection rate of this high-redshift, low-flux-density sample is 90%, with only one target (J0306+1853) remaining undetected. The other 9 sources appear core-dominated and show a single, faint and compact radio core on this angular scale. The derived radio powers are typical of FRII radio galaxies and quasars. By extending our sample with other VLBI-detected z > 5 sources from the literature, we found that the core brightness temperatures and monochromatic radio powers tend to increase with radio loudness.
title Revealing faint compact radio jets at redshifts above 5 with very long baseline interferometry
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2406.05192