- document
-
Frey, Sándor (author), An, Tao (author), Gabányi, Krisztina (author), Gurvits, L. (author), Krezinger, Máté (author), Melnikov, Alexey (author), Mohan, Prashanth (author), Paragi, Zsolt (author), Perger, Krisztina (author)The powerful high-redshift quasar J2102+6015 (at z = 4.575) may provide useful information for studying supermassive black hole growth, galaxy evolution and feedback in the early Universe. The source has so far been imaged with very-long-baseline interferometry (VLBI) at 2/8 GHz (S/X) bands only, showing complex compact structure. Its total...journal article 2023
- document
-
Perger, Krisztina (author), Zhang, Yingkang (author), Frey, Sándor (author), An, Tao (author), Gabányi, Krisztina E. (author), Gurvits, L. (author), Hwang, Chorng Yuan (author), Koptelova, Ekaterina (author), Paragi, Zsolt (author), Wang, Ailing (author)There are approximately 250 quasars discovered at redshift z ≥ 6, of which only a handful were detected in radio bands, and even fewer were imaged with the highest resolution very long baseline interferometry (VLBI) technique. Here we report the results of our dual-frequency observations with the Very Long Baseline Array (VLBA) of two such...journal article 2023
- document
-
Krezinger, Máté (author), Perger, Krisztina (author), Gabányi, Krisztina Éva (author), Frey, Sándor (author), Gurvits, L. (author), Paragi, Zsolt (author), An, Tao (author), Zhang, Yingkang (author), Cao, Hongmin (author), Sbarrato, Tullia (author)High-redshift radio sources provide plentiful opportunities for studying the formation and evolution of early galaxies and supermassive black holes. However, the number of known radio-loud active galactic nuclei (AGN) above redshift 4 is rather limited. At high redshifts, it appears that blazars, with relativistically beamed jets pointing...journal article 2022
- document
-
Gabányi, Krisztina (author), Frey, Sándor (author), An, Tao (author), Cao, Hongmin (author), Paragi, Zsolt (author), Gurvits, L. (author), Zhang, Yingkang (author), Sbarrato, Tullia (author), Krezinger, Máté (author)Less than 200 radio-loud active galactic nuclei are known above redshift 4. Around 40 of them have been observed at milliarcsecond (mas) scale resolution with very long baseline interferometry (VLBI) technique. Some of them are unresolved, compact, relativistically beamed objects, and blazars with jets pointing at small angles to the observer...journal article 2021
- document
-
An, Tao (author), Mohan, Prashanth (author), Zhang, Yingkang (author), Frey, Sándor (author), Yang, J. (author), Gabányi, Krisztina (author), Gurvits, L. (author), Paragi, Zsolt (author), Perger, Krisztina (author), Zheng, Zhenya (author)Blazars are a sub-class of quasars with Doppler boosted jets oriented close to the line of sight, and thus efficient probes of supermassive black hole growth and their environment, especially at high redshifts. Here we report on Very Long Baseline Interferometry observations of a blazar J0906 + 6930 at z = 5.47, which enabled the detection of...journal article 2020