@booklet {30255,
	title = {A multi-messenger study of the blazar PKS 0735+178: a new major neutrino source candidate},
	year = {2022},
	month = {2022/04/1},
	pages = {arXiv:2204.05060},
	abstract = {PKS 0735+178 is a bright radio and $\gamma$-ray blazar that is possibly associated with multiple neutrino events observed by the IceCube, Baikal, Baksan, and KM3NeT neutrino telescopes. The source was found to undergo a major flaring activity in $\gamma$-ray, X-ray, ultraviolet (UV) and optical bands. We present a long-term detailed study of this peculiar blazar to investigate the temporal and spectral changes in the multi-wavelength 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 $5\times10^3$ seconds during the observation on December 17, 2021. In the $\gamma$-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 $\gamma$-ray powers, and parsec scale jet properties. Moreover, PKS 0735+178, like all the others, is 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 $\sim$ PeV protons with an external UV photon field. This scenario predicts $\sim 0.067$ muon and antimuon 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},
	url = {https://ui.adsabs.harvard.edu/abs/2022arXiv220405060S},
	author = {Sahakyan, N. and Giommi, P. and Padovani, P. and Petropoulou, M. and B{\'e}gu{\'e}, D. and Boccardi, B. and Gasparyan, S.}
}
