  The discovery of high-energy astrophysical neutrinos by IceCube kicked off a
new line of research to identify the electromagnetic counterparts producing
these neutrinos. Among the extragalactic sources, active galactic nuclei (AGN),
and in particular Blazars, are promising candidate neutrino emitters. Their
structure, with a relativistic jet pointing to the Earth, offers a natural
accelerator of particles and for this reason a perfect birthplace of high
energy neutrinos. A good characterisation of the spectral energy distribution
(SED) of these sources can improve the understanding of the physical
composition of the source and the emission processes involved. Starting from
our previous works in which we assumed a correlation between the $\gamma$-ray
and the neutrino flux of the BL Lacs of the 2FHL catalogue (detected by Fermi
above 50GeV), we select those BL Lac in spatial correlation with the IceCube
events. We obtain a sample of 7 sources and we start an observational campaign
to have a better characterisation of the synchrotron peak. During the analysis
of the data a new source has been added because of its position inside the
angular uncertainty of a muon track event detected by IceCube. This source,
namely TXS0506+056, was in a high-state during the neutrino event and we will
consider it as benchmark to check the proprieties of the other sources of the
sample during the related neutrino detection.
  We obtain a better characterisation of the SED for the sources of our sample.
A prospective extreme Blazar, a very peculiar low synchrotron peak (LSP) source
with a large separation of the two peaks and a \textit{twin} of TXS0506+056
come up. We also provide the $\gamma$-ray light curve to check the trend of the
sources around the neutrino detection but no clears patterns are in common
among the sources.
