Varstrometry for Off-nucleus and Dual Sub-kiloparsec Active Galactic Nuclei (VODKA): Very Long Baseline Array Searches for Dual or Off-nucleus Quasars and Small-scale Jets

Dual and off-nucleus active supermassive black holes are expected to be common in the hierarchical structure formation paradigm, but their identification at parsec scales remains a challenge due to strict angular resolution requirements. We conducted a systematic study using the Very Long Baseline A...

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Veröffentlicht in:The Astrophysical journal Jg. 958; H. 1; S. 29 - 42
Hauptverfasser: Chen, Yu-Ching, Liu, Xin, Lazio, Joseph, Breiding, Peter, Burke-Spolaor, Sarah, Hwang, Hsiang-Chih, Shen, Yue, Zakamska, Nadia L.
Format: Journal Article
Sprache:Englisch
Veröffentlicht: Philadelphia The American Astronomical Society 01.11.2023
IOP Publishing
Schlagworte:
Active galactic nuclei
Angular resolution
Arrays
Astrometry
Astronomical techniques
Astrophysics
Black holes
Candidates
Coordinate systems
Coordinates
Double quasars
Gaia
Galaxies
Jets
Offsets
Quasars
Radio emission
Radio jets
Radio loud quasars
Supermassive black holes
Very Long Baseline Array (VLBA)
Very long baseline interferometers
Vodka
ISSN:0004-637X, 1538-4357
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Zusammenfassung:Dual and off-nucleus active supermassive black holes are expected to be common in the hierarchical structure formation paradigm, but their identification at parsec scales remains a challenge due to strict angular resolution requirements. We conducted a systematic study using the Very Long Baseline Array (VLBA) to examine 23 radio-bright candidate dual and off-nucleus quasars. The targets are selected by a novel astrometric technique ( varstrometry ) from Gaia, aiming to identify dual or off-nucleus quasars at (sub)kiloparsec scales. Among these quasars, eight exhibit either multiple radio components or significant (>3 σ ) positional offsets between the VLBA and Gaia positions. The radio emission from the three candidates, which exhibit multiple radio components, is likely to originate from small-scale jets based on their morphology. Among the remaining five candidates with significant VLBA-Gaia offsets, three are identified as potential dual quasars at parsec scales, one is likely attributed to small-scale jets, and the origin of the last candidate remains unclear. We explore alternative explanations for the observed VLBA-Gaia offsets. We find no evidence for optical jets at kiloparsec scales, nor any contamination to Gaia astrometric noise from the host galaxy; misaligned coordinate systems are unlikely to account for our offsets. Our study highlights the promise of the varstrometry technique in discovering candidate dual or off-nucleus quasars and emphasizes the need for further confirmation and investigation to validate and understand these intriguing candidates.
Bibliographie:AAS48159
Galaxies and Cosmology
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ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ad00b3