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From Variability to Spectral Energy Distribution Modeling: A Multiwavelength Study of the Neutrino Blazar TXS 0506+056

Year: 2026
Type: article
Abstract: The blazar TXS 0506+056 is the first source that was reported to be associated with high-energy extragalactic neutrino events and is one of the major targets for multimessenger studies. We carried out multiwavelength optical monitoring of this object on 24 nights in the period from 2018 to 2023. The overall light curves exhibit a dimming trend superposed by some small-amplitude fluctuations, and intraday variability was detected on four nights. Bluer-when-brighter behaviors were observed on both intraday and long timescales and were more pronounced on long timescales, while a weak redder-when-brighter trend was detected on one night. No significant time lags were found between variations at different optical wavelengths. We also retrieved the multibroadband data from some monitoring programs. The data reveal complex, asynchronous flaring in different wavebands. A cross-correlation analysis shows that the high-energy emission (optical to γ -ray) is cospatial and leads the radio emission by a substantial time of ∼800–900 days, suggesting that the radio emission originates from a downstream region of the jet. We performed time-dependent leptohadronic modeling of the spectral energy distributions for three representative epochs—the 2017 neutrino-associated flare, a postflare phase, and a deep quiescent state—revealing an evolution in the radiative properties of the emission regions. The modeling results provide a phenomenological framework for interpreting the long-term multiwavelength behavior of TXS 0506+056 in a multimessenger context.
DOI: 10.3847/1538-4357/ae990f
Language: English
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W7214982131
FWCI:
Cites: 88
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Related to: 10