VLBI observations of VIK J2318−3113, a quasar at z = 6.44
Abstract
Context. The nature of jets in active galactic nuclei (AGNs) in the early Universe and their feedback to the host galaxy remains a highly topical question. Observations of the radio structure of high-redshift AGNs enabled by very long baseline interferometry (VLBI) provide indispensable input into studies of their properties and role in the galaxies' evolution. To date, only five AGNs at redshift z > 6 have been studied with the VLBI technique.
Aims: VIK J2318−3113 is a recently discovered quasar at z = 6.44 that had not been imaged with VLBI before the current work. Here we present the first VLBI imaging results of this high-redshift quasar, with the aim of corroborating its high-resolution appearance with the physical model of the object.
Methods: We carried out VLBI phase-referencing observations of VIK J2318−3113 using the Very Long Baseline Array at two frequencies, 1.6 and 4.7 GHz, and obtained the first view at the radio structure on the milliarcsecond scale.
Results: The source was clearly detected at 1.6 GHz. We found that almost all of its radio emission comes from the parsec-scale core region. Our dual-frequency observations constrain the spectral index and brightness temperature of the radio core. Its properties are similar to those of other known high-redshift radio-loud AGNs.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- June 2022
- DOI:
- 10.1051/0004-6361/202243785
- arXiv:
- arXiv:2205.05859
- Bibcode:
- 2022A&A...662L...2Z
- Keywords:
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- galaxies: jets;
- galaxies: high-redshift;
- quasars: general;
- quasars: individual: VIK J2318−3113;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena;
- High Energy Physics - Experiment;
- High Energy Physics - Phenomenology
- E-Print:
- 6 pages, 2 figures, accepted by A&