Year: 2026
Type: article
Abstract: When blazars flare, their optical position moves. We show this by combining Gaia DR3 proper motions with epoch photometry for blazars with strong optical jet emission. In 60 of 74 sources with significant proper motion, rising flux drives the centroid upstream while fading flux drives it downstream—a near-universal pattern captured by a simple two-component model of constant extended emission and a flaring region. Using this connection, we geometrically localize the optical flares to within <1 mas of the very long baseline interferometry position—a few parsecs at typical blazar distances—placing them in the innermost jet or accretion disk. This purely geometric method requires no multiwavelength correlations or model-dependent assumptions. It provides an independent anchor for localizing higher-energy flares and constrains the particle acceleration site in blazars. Per-epoch astrometry from Gaia DR4 is set to tighten our localizations even further.
Author: A. V. Plavin
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
OpenAlex ID: W7169772202