Dissecting the AGN Disk-Jet System with Joint VLBI-Gaia Analysis

We analyze differences in positions of active galactic nuclei (AGNs) between Gaia data release 2 and very long baseline interferometry (VLBI) and compare the significant VLBI-to-Gaia offsets in more than 1000 objects with their jet directions. Remarkably at least three-fourths of the significant off...

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Bibliographic Details
Published in:The Astrophysical journal 2019-02, Vol.871 (2), p.143
Main Authors: Plavin, A. V., Kovalev, Y. Y., Petrov, L. Y.
Format: Article
Language:English
Subjects:
Accretion
Accretion disks
accretion, accretion disks
Active galactic nuclei
Astrophysics
BL Lacertae objects
BL Lacertae objects: general
Downstream effects
Emission
Galaxies
galaxies: active
galaxies: jets
galaxies: Seyfert
Interferometry
Offsets
Quasars
quasars: general
Radio jets (astronomy)
Red shift
Seyfert galaxies
Space Radiation
Stars & galaxies
Toruses
Upstream
Very long base interferometry
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Summary:We analyze differences in positions of active galactic nuclei (AGNs) between Gaia data release 2 and very long baseline interferometry (VLBI) and compare the significant VLBI-to-Gaia offsets in more than 1000 objects with their jet directions. Remarkably at least three-fourths of the significant offsets are confirmed to occur downstream or upstream of the jet representing a genuine astrophysical effect. Introducing redshift and Gaia color into analysis can help distinguish between the contribution of the host galaxy, jet, and accretion disk emission. We find that strong optical jet emission at least 20-50 pc long is required to explain the Gaia positions located downstream from VLBI ones. Offsets in the upstream direction of up to 2 mas are at least partly due to the dominant impact of the accretion disk on the Gaia coordinates and by the effects of the parsec-scale radio jet. The host galaxy was found not to play an important role in the detected offsets. BL Lacertae object and Seyfert 2 galaxies are observationally confirmed to have a relatively weak disk and consequently downstream offsets. The disk emission drives upstream offsets in a significant fraction of quasars and Seyfert 1 galaxies when it dominates over the jet in the optical band. The observed behavior of the different AGN classes is consistent with the unified scheme assuming varying contribution of the obscuring dusty torus and jet beaming.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/aaf650