BLAZ4R and the eROSITA view of z>4 blazars

Fuente: arXiv
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Main Authors: Sbarrato, Tullia, Belladitta, Silvia, Wolf, Julien, Baldini, Pietro, Tubín-Arenas, Dusan, Salvato, Mara, Momjian, Emmanuel, Hämmerich, Steven, Merloni, Andrea, Collmar, Werner, Wilms, Joern
Format: Preprint
Published: 2026
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author Sbarrato, Tullia
Belladitta, Silvia
Wolf, Julien
Baldini, Pietro
Tubín-Arenas, Dusan
Salvato, Mara
Momjian, Emmanuel
Hämmerich, Steven
Merloni, Andrea
Collmar, Werner
Wilms, Joern
author_facet Sbarrato, Tullia
Belladitta, Silvia
Wolf, Julien
Baldini, Pietro
Tubín-Arenas, Dusan
Salvato, Mara
Momjian, Emmanuel
Hämmerich, Steven
Merloni, Andrea
Collmar, Werner
Wilms, Joern
contents We present BLAZ4R, the first living catalog of confirmed $z>4$ blazars, with a focus on the contribution of eROSITA, on board of the Spectrum Roentgen Gamma (SRG) spacecraft. Blazars at $z>4$ are rare but powerful probes of how active supermassive black holes evolve in connection to relativistic jets, in the first 2 billion years of cosmic history. At these redshifts, X-ray observations are essential for constraining blazars jet power and orientation, enabling effective trace of their parent population. The all-sky surveys provided by eROSITA ensure X-ray detection for BLAZ4R sources and, in some cases, allow spectral and temporal studies of their jetted emission. BLAZ4R includes 54 confirmed blazars, characterized through their X-ray properties, radio spectra and morphology, and multiwavelength profiles. We confirm that jetted sources are significantly more numerous relative to non-jetted counterparts at high-$z$, and that blazars (and therefore the overall jetted population) do not exhibit significantly different features compared to the total active galactic nuclei population in the early Universe. Fast accretion processes that involve relativistic jets are clearly required to justify the existence of fully formed jetted AGN at $z>4$. However, the diverse multiwavelength properties characterizing BLAZ4R do not yet allow us to identify the specific signatures of these processes. We will continue updating BLAZ4R to search for such signatures and ultimately understand the early formation of jetted AGN.
format Preprint
id arxiv_https___arxiv_org_abs_2603_24659
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle BLAZ4R and the eROSITA view of z>4 blazars
Sbarrato, Tullia
Belladitta, Silvia
Wolf, Julien
Baldini, Pietro
Tubín-Arenas, Dusan
Salvato, Mara
Momjian, Emmanuel
Hämmerich, Steven
Merloni, Andrea
Collmar, Werner
Wilms, Joern
High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
We present BLAZ4R, the first living catalog of confirmed $z>4$ blazars, with a focus on the contribution of eROSITA, on board of the Spectrum Roentgen Gamma (SRG) spacecraft. Blazars at $z>4$ are rare but powerful probes of how active supermassive black holes evolve in connection to relativistic jets, in the first 2 billion years of cosmic history. At these redshifts, X-ray observations are essential for constraining blazars jet power and orientation, enabling effective trace of their parent population. The all-sky surveys provided by eROSITA ensure X-ray detection for BLAZ4R sources and, in some cases, allow spectral and temporal studies of their jetted emission. BLAZ4R includes 54 confirmed blazars, characterized through their X-ray properties, radio spectra and morphology, and multiwavelength profiles. We confirm that jetted sources are significantly more numerous relative to non-jetted counterparts at high-$z$, and that blazars (and therefore the overall jetted population) do not exhibit significantly different features compared to the total active galactic nuclei population in the early Universe. Fast accretion processes that involve relativistic jets are clearly required to justify the existence of fully formed jetted AGN at $z>4$. However, the diverse multiwavelength properties characterizing BLAZ4R do not yet allow us to identify the specific signatures of these processes. We will continue updating BLAZ4R to search for such signatures and ultimately understand the early formation of jetted AGN.
title BLAZ4R and the eROSITA view of z>4 blazars
topic High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2603.24659