@article {39996,
	title = {A multimessenger study of the blazar PKS 0735+178: a new major neutrino source candidate},
	volume = {519},
	year = {2023},
	month = {2023/02/1},
	pages = {1396 - 1408},
	publisher = {OUP},
	abstract = {The blazar PKS 0735+178 is possibly associated with multiple neutrino events observed by the IceCube, Baikal, Baksan, and KM3NeT neutrino telescopes while it was flaring in the γ-ray, X-ray, ultraviolet, and optical bands. We present a detailed study of this peculiar blazar to investigate the temporal and spectral changes in the multiwavelength emission when the neutrino events were observed. The analysis of Swift-XRT snapshots reveal a flux variability of more than a factor 2 in about 5 {\texttimes} 10<SUP>3</SUP> s during the observation on 2021 December 17. In the γ-ray band, the source was in its historical highest flux level at the time of the arrival of the neutrinos. The observational comparison between PKS 0735+178 and other neutrino source candidates, such as TXS 0506+056, PKS 1424+240, and GB6 J1542+6129, shows that all these sources share similar spectral energy distributions, very high radio and γ-ray powers, and parsec scale jet properties. Moreover, we present strong supporting evidence for PKS 0735+178 to be, like all the others, a masquerading BL Lac. We perform comprehensive modelling of the multiwavelength emission from PKS 0735+178 within one-zone lepto-hadronic models considering both internal and external photon fields and estimate the expected accompanying neutrino flux. The most optimistic scenario invokes a jet with luminosity close to the Eddington value and the interactions of ~ PeV protons with an external UV photon field. This scenario predicts ~0.067 muon and anti-muon neutrinos over the observed 3-week flare. Our results are consistent with the detection of one very high-energy neutrino like IceCube-211208A.},
	keywords = {Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, gamma-rays: galaxies, neutrinos, radiation mechanisms: non-thermal, X-rays: galaxies},
	isbn = {0035-8711},
	url = {https://ui.adsabs.harvard.edu/abs/2023MNRAS.519.1396S},
	author = {Sahakyan, N. and Giommi, P. and Padovani, P. and Petropoulou, M. and B{\'e}gu{\'e}, D. and Boccardi, B. and Gasparyan, S.}
}
