Publications (15)
Zooming into the neutrino-associated blazar candidate J1718+4239
K. Perger, S. Frey, K. Ã. Gabányi +1
The radio quasar NVSS~J171822+423948 (J1718+4239) was proposed as the counterpart of the IceCube neutrino event IC-201221A. To reveal the nature of the source, we conducted new ver…
VLBI observations of VIK J2318-3113, a quasar at z = 6.44
Y. Zhang, T. An, A. Wang +5
The nature of jets in active galactic nuclei (AGN) in the early Universe and their feedback to the host galaxy remain a highly topical question. Observations of the radio structure…
Deep silence: radio properties of little red dots
K. Perger, J. Fogasy, S. Frey +1
To investigate the radio properties of the recently found high-redshift population, we collected a sample of little red dots (LRDs) from the literature. By cross-matching the…
Radio emission from flaring stars and brown dwarfs
K. Perger, B. Seli, K. Vida
Aims. With the aim to reveal the effects of the magnetic field to the multi-band activity of dwarf stars, we search for associated radio emission for an extensive list of 14 915 br…
From compact jets to extended lobes: radio morphologies of distant quasars at z > 4
K. Ã. Gabányi, M. Kunert-Bajraszewska, A. Krauze +9
High-redshift quasars play an essential role in studying the growth and evolution of supermassive black holes and active galactic nuclei (AGN). Radio-loud quasars additionally enab…
J2102+6015: an Intriguing Radio-loud Active Galactic Nucleus in the Early Universe
S. Frey, T. An, K. Gabányi +10
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 Uni…
SKAVLBI view of AGN jets in the early Universe
C. Spingola, M. Mezcua, Y. Liu +33
Active Galactic Nuclei (AGN) are among the brightest sources in the Universe, and those that are also jetted are uniquely valuable at the earliest epochs, because their relativisti…
Very long baseline interferometry observations of the high-redshift blazar candidate J0141-5427
K. Ã. Gabányi, S. Belladitta, S. Frey +7
Active galactic nuclei (AGN) have been observed as far as redshift z~7. They are crucial in investigating the early Universe as well as the growth of supermassive black holes at th…
Constraining the radio jet proper motion of the high-redshift quasar J2134-0419 at z=4.3
K. Perger, S. Frey, K. Ã. Gabányi +12
To date, PMN J2134-0419 (at a redshift z=4.33) is the second most distant quasar known with a milliarcsecond-scale morphology permitting direct estimates of the jet proper motion.…
Milliarcsecond-scale radio structure of the most distant BL Lac object candidate at redshift 6.57
S. Frey, Y. Zhang, K. Perger +7
The existence of accreting supermassive black holes up to billions of solar masses at early cosmological epochs (in the context of this work, redshifts z>=6) requires very fast gro…
High-Resolution Radio Image of a Candidate Radio Galaxy at z=5.72
K. Ã. Gabányi, S. Frey, L. I. Gurvits +2
Recently, Saxena et al. (2018) reported the discovery of a possible radio galaxy, J15301049 at a redshift of z=5.72. We observed the source with the European Very Long Baseline…
High-resolution radio imaging of TGSSJ1530+1049, a radio galaxy in a dense environment at z=4
K. Ã. Gabányi, S. Frey, L. I. Gurvits +10
High-redshift radio galaxies can provide insights into the structure formation and galaxy evolution at earlier cosmological epochs. TGSSJ1530+1049 was selected as a candidate high-…
Solid Identification of Extragalactic Gamma-Ray Source Using High-Resolution Radio Interferometric Observation
K. Ã. Gabányi, S. Frey, K. Perger +1
The dominant fraction of the extragalactic -ray sources are blazars, active galactic nuclei with jets inclined at a small angle to the line of sight. Apart from blazars, a few…
Radio-loud Quasars above Redshift 4: VLBI Imaging of an Extended Sample
M. Krezinger, K. Perger, K. Ã. Gabányi +7
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 ra…
Three little radio galaxies in the early Universe
K. Ã. Gabányi, S. Frey, Z. Paragi +7
Volonteri et al. (2011) found that the number of radio-loud quasars above redshift 4 calculated from the luminosity function (based upon Swift/BAT observations) is much smaller tha…