Stellar populations of the bulges of four spiral galaxies
  Key information to understand the formation and evolution of disk galaxies
are imprinted in the stellar populations of their bulges. This paper has the
purpose to make available new measurements of the stellar population properties
of the bulges of four spiral galaxies. Both the central values and radial
profiles of the line strength of some of the most common Lick indices are
measured along the major- and minor- axis of the bulge-dominated region of the
sample galaxies. The corresponding age, metallicity, and {\alpha}/Fe ratio are
derived by using the simple stellar population synthesis model predictions. The
central values and the gradients of the stellar population properties of
ESO-LV1890070, ESO-LV4460170, and ESO-LV 5140100 are consistent with previous
findings for bulges of spiral galaxies. On the contrary, the bulge of ESO-LV
4500200 shows peculiar chemical properties possibly due to the presence of a
central kinematically-decoupled component. The negative metallicity gradient
found in our bulges sample indicates a relevant role for the dissipative
collapse in bulge formation. However, the shallow gradients found for the age
and {\alpha}/Fe ratio suggests that merging can not be completely ruled out for
the sample bulges. This is confirmed by the properties of ESO-LV 4500200 which
can hardly be explained without invoking the capture of external material.
