Revealing a multi-zone circumnuclear dust response in UGC 11487 through phase-resolved WISE W1--W2 diagnostics
Year: 2026
Type: preprint
Abstract: Mid-infrared (MIR) flares provide a direct probe of dust reprocessing in obscured tidal disruption event (TDE) candidates when the primary optical or ultraviolet flare is weak, missed, or strongly attenuated. We present a phase-resolved analysis of the WISE/NEOWISE W1-W2 evolution of the MIR-selected TDE candidate UGC 11487/WTP14adeqka over 2014-2024. We combine timing, colour, and flux diagnostics with phenomenological modelling, hydrodynamically motivated clumpy dust-echo calculations, and an aperture-matched ultraviolet-to-radio spectral energy distribution of the host. The decade-long flare shows a delayed and broader W2 response, colour hysteresis, and cooling from approximately 900 K to 500-600 K. Positive-fluence centroids yield a preferred delay of $224 +/- 45$ d, corresponding to $0.188 +/- 0.038$ pc. The effective infrared luminosity peaks at approximately $3 x 10^{43}$ erg s$^{-1}$, and the integrated infrared energy is $(2.9-3.8) x 10^{51}$ erg. A single self-similar MIR response is strongly disfavoured, with Delta BIC = 281.7, while the preferred compact description is a two-component phenomenological model. Representative hydro-clumpy calculations reproduce the empirical diagnostics in a structured, multi-zone dust-response scenario. The host is a moderately star-forming isolated barred disc without a dominant persistent active galactic nucleus component. These results support an obscured TDE-like accretion transient reprocessed by structured circumnuclear dust and show that phase-resolved WISE diagnostics can recover characteristic sub-parsec response scales in obscured accretion-powered nuclear transients.
Source: arXiv (Cornell University)
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, California Institute of Technology, Northwestern University, Drexel University, National Research Foundation of Ukraine, University of Warwick, National Research Foundation, Stockholms Universitet, Jet Propulsion Laboratory
OpenAlex ID: W7169830835