  The existence of asymmetries in the circular polarization (Stokes V) profiles
emerging from the solar photosphere is known since the 1970s. These profiles
require the presence of a velocity gradient along the line of sight, possibly
associated with gradients of magnetic field strength, inclination and/or
azimuth. We have focused our study on the Stokes V profiles showing extreme
asymmetry in the from of only one lobe. Using Hinode spectropolarimetric
measurements we have performed a statistical study of the properties of these
profiles in the quiet sun. We show their spatial distribution, their main
physical properties, how they are related with several physical observables and
their behavior with respect to their position on the solar disk. The single
lobed Stokes V profiles occupy roughly 2% of the solar surface. For the first
time, we have observed their temporal evolution and have retrieved the physical
conditions of the atmospheres from which they emerged using an inversion code
implementing discontinuities of the atmospheric parameters along the line of
sight. In addition, we use synthetic Stokes profiles from 3D magnetoconvection
simulations to complement the results of the inversion. The main features of
the synthetic single-lobed profiles are in general agreement with the observed
ones, lending support to the magnetic and dynamic topologies inferred from the
inversion. The combination of all these different analysis suggests that most
of the single-lobed Stokes V profiles are signals coming from magnetic flux
emergence and/or submergence processes taking place in small patches in the
photospheric of the quiet sun.
