450 citations · 2.1k across the 56 of their papers we have counts for
58 papers
From compact jets to extended lobes: radio morphologies of distant quasars at z > 4
K. É. 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…
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…
BLAZ4R and the eROSITA view of z>4 blazars
Tullia Sbarrato, Silvia Belladitta, Julien Wolf +8
We present BLAZ4R, the first living catalog of confirmed blazars, with a focus on the contribution of eROSITA, on board of the Spectrum Roentgen Gamma (SRG) spacecraft. Blaza…
BL Lac host galaxies: how to systematically characterise them in optical-NIR spectroscopy
Gaia Delucchi, Tullia Sbarrato, Giorgio Calderone +3
Host galaxies of Active Galactic Nuclei give crucial information on the interaction between accreting Supermassive Black Holes and their surroundings, and on their common evolution…
The IXPE and multifrequency polarimetric view of the extreme blazars 1ES 1101-232 and RGB J0710+591
Fabrizio Tavecchio, Dawoon E. Kim, Gabriel Emery +53
Multiwavelength polarimetry is a powerful tool to probe magnetic field and flow geometries in the relativistic jets of blazars. In this respect, particularly interesting are the so…
Ultra-extreme high-frequency-peaked BL Lacs: A potential population of MeV synchrotron blazars
A. Sciaccaluga, F. Tavecchio, T. Sbarrato +1
We investigate the potential existence of a new population of BL Lacs, called ultra-extreme high-energy-peaked BL Lacs (UEHBLs), whose synchrotron emission component peaks in the M…
BlazEr1: The eROSITA Blazar Catalog. Blazars and Blazar Candidates in the First eROSITA Survey
S. Haemmerich, A. Gokus, F. McBride +28
Aims. eROSITA, on board the Spectrum Roentgen Gamma (SRG) spacecraft, performed its first X-ray all-sky survey (eRASS1) between December 2019 and June 2020. It detected about 93000…
Supermassive black holes and their surroundings: MeV signatures
Tullia Sbarrato, Marco Ajello, Sara Buson +5
The gravitational potential of supermassive black holes is so powerful that it triggers some of the most intense phenomena in the Universe. Accretion onto these objects and relativ…
NVSS J151002+570243: accretion and spin of a z > 4 Fermi detected blazar
Gabriele Alzati, Tullia Sbarrato, Gabriele Ghisellini
Active galactic nuclei formation and evolution is currently an open puzzle. Their enormous mass is not explainable via sub-Eddington accretion and the frequent presence of relativi…
Revealing faint compact radio jets at redshifts above 5 with very long baseline interferometry
Máté Krezinger, Giovanni Baldini, Marcello Giroletti +6
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) obser…
The SRG/eROSITA All-Sky Survey: X-ray beacons at late cosmic dawn
J. Wolf, M. Salvato, S. Belladitta +12
The SRG/eROSITA All-Sky Survey (eRASS) is expected to contain ~100 quasars that emitted their light when the universe was less than a billion years old, i.e. at z>5.6. By selection…
The High Energy X-ray Probe (HEX-P): the most powerful jets through the lens of a superb X-ray eye
Lea Marcotulli, Marco Ajello, Markus Böttcher +20
A fraction of the active supermassive black holes at the centers of galaxies in our Universe are capable of launching extreme kiloparsec-long relativistic jets. These jets are know…
A search for the afterglows, kilonovae, and host galaxies of two short GRBs: GRB 211106A and GRB 211227A
M. Ferro, R. Brivio, P. D'Avanzo +30
Context: GRB 211106A and GRB 211227A are recent gamma-ray bursts (GRBs) with initial X-ray positions suggesting associations with nearby galaxies (z < 0.7). Their prompt emission c…
Subarcsecond view on the high-redshift blazar GB 1508+5714 by the International LOFAR Telescope
A. Kappes, P. R. Burd, M. Kadler +14
Studies of the most distant AGNs allow us to test our current understanding of the physics present in radio-jetted AGNs across a range of environments. The decrease in apparent lum…
Radio-loud Quasars above Redshift 4: VLBI Imaging of an Extended Sample
M. Krezinger, K. Perger, K. É. 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…
Blazar nature of high-z radio-loud quasars
Tullia Sbarrato, Gabriele Ghisellini, Gianpiero Tagliaferri +3
We report on the Swift/XRT observation and classification of eleven blazar candidates at . These sources were selected as part of a sample of extremely radio-loud quasars, in…
Direct observation of an extended X-ray jet at =6.1
L. Ighina, A. Moretti, F. Tavecchio +6
We report on the direct observation of an extended X-ray jet in the =6.1 radio-loud Active Galactic Nucleus PSO J030947.49+271757.31 from a deep Chandra X-ray observation (128 k…
A small radio galaxy at z=4.026
Krisztina É. Gabányi, Sándor Frey, Tao An +8
Less than radio-loud active galactic nuclei (AGN) are known above redshift . Around of them have been observed at milliarcsecond (mas) scale resolution with very long…
Jetted radio-quiet quasars at z>5
Tullia Sbarrato, Gabriele Ghisellini, Gabriele Giovannini +1
We report on the JVLA observations of three high redshift Active Galactic Nuclei (AGN), having a black hole mass estimated to be among the largest known. Two of them, SDSS J0100+28…
The disk-torus system in active galactic nuclei: possible evidence of highly spinning black holes
Samuele Campitiello, Annalisa Celotti, Gabriele Ghisellini +1
We study the ratio between the luminosity of the torus and that of the accretion disk, inferred from the relativistic model KERRBB for a sample of approximately 2000 luminosity…
Big and young supermassive black holes in the early Universe
Tullia Sbarrato
Blazars are Active Galactic Nuclei characterized by relativistic jets launched in the vicinity of the central engine (i.e. a supermassive black hole), that are oriented close to ou…
Minute-timescale variability in the X-ray emission of the highest redshift blazar
Alberto Moretti, Gabriele Ghisellini, Alessandro Caccianiga +9
We report on two Chandra observations of the quasar PSO J0309+27, the most distant blazar observed so far (z=6.1), performed eight months apart, in March and November 2020. Previou…
A new panchromatic classification of unclassified Burst Alert Telescope active galactic nuclei
Luca Giuliani, Gabriele Ghisellini, Tullia Sbarrato
We collect data at all frequencies for the new sources classified as unknown active galactic nuclei (AGNs) in the latest Burst Alert Telescope (BAT) all-sky hard X-ray catalog. Foc…
VLBI20-30: a scientific roadmap for the next decade -- The future of the European VLBI Network
Tiziana Venturi, Zsolt Paragi, Michael Lindqvist +77
This white paper describes the science case for Very Long Baseline Interferometry (VLBI) and provides suggestions towards upgrade paths for the European VLBI Network (EVN). The EVN…