TXS 0506+056, the first cosmic neutrino source, is not a BL Lac
  We present evidence that TXS 0506+056, the first plausible non-stellar
neutrino source, despite appearances, is not a blazar of the BL Lac type but is
instead a masquerading BL Lac, i.e., intrinsically a flat-spectrum radio quasar
with hidden broad lines and a standard accretion disk. This re-classification
is based on: (1) its radio and O II luminosities; (2) its emission line ratios;
(3) its Eddington ratio. We also point out that the synchrotron peak frequency
of TXS 0506+056 is more than two orders of magnitude larger than expected by
the so-called "blazar sequence", a scenario which has been assumed by some
theoretical models predicting neutrino (and cosmic-ray) emission from blazars.
Finally, we comment on the theoretical implications this re-classification has
on the location of the $\gamma$-ray emitting region and our understanding of
neutrino emission in blazars.
