English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Dual and off-nucleus active supermassive black holes are expected to becommon in the hierarchical structure formation paradigm, but theiridentification at parsec scales remains a challenge due to strict angularresolution requirements. We conduct a systematic study using the Very LongBaseline Array (VLBA) to examine 23 radio-bright candidate dual and off-nucleusquasars. The targets are selected by a novel astrometric technique("varstrometry") from Gaia, aiming to identify dual or off-nucleus quasars at(sub)kilo-parsec scales. Among these quasars, 8 exhibit either multiple radiocomponents or significant (>3$\sigma$) positional offsets between the VLBA andGaia positions. The radio emission from the three candidates which exhibitmultiple radio components is likely to originate from small-scale jets based ontheir morphology. Among the remaining five candidates with significantVLBA-Gaia offsets, three are identified as potential dual quasars at parsecscales, one is likely attributed to small-scale jets, and the origin of thelast candidate remains unclear. We explore alternative explanations for theobserved VLBA-Gaia offsets. We find no evidence for optical jets at kilo-parsecscales, nor any contamination to Gaia astrometric noise from the host galaxy;misaligned coordinate systems are unlikely to account for our offsets. Ourstudy highlights the promise of the varstrometry technique in discoveringcandidate dual or off-nucleus quasars and emphasizes the need for furtherconfirmation and investigation to validate and understand these intriguingcandidates.

Varstrometry for Off-nucleus and Dual Sub-kpc AGN (VODKA): Very Long Baseline Array Searches for Dual or Off-nucleus Quasars and Small-scale Jets