Context : Satellite accretion events have been invoked for mimicking the internal secular evolutionary processes of bulge growth .
However , N-body simulations of satellite accretions have paid little attention to the evolution of bulge photometric parameters , to the processes driving this evolution , and to the consistency of this evolution with observations .

Aims : We want to investigate whether satellite accretions indeed drive the growth of bulges , and whether they are consistent with global scaling relations of bulges and discs .

Methods : We perform N -body models of the accretion of satellites onto disc galaxies .
A Tully-Fisher ( M \propto V _ { rot } ^ { \alpha _ { \mathrm { { \small TF } } } } ) scaling between primary and satellite ensures that density ratios , critical to the outcome of the accretion , are realistic .
We carry out a full structural , kinematic and dynamical analysis of the evolution of the bulge mass , bulge central concentration , and bulge-to-disc scaling relations .

Results : The remnants of the accretion have bulge-disc structure .
Both the bulge-to-disc ratio ( B / D ) and the Sérsic index ( n ) of the remnant bulge increase as a result of the accretion , with moderate final bulge Sérsic indices : n = 1.0 to 1.9 .
Bulge growth occurs no matter the fate of the secondary , which fully disrupts for { \alpha _ { \mathrm { { \small TF } } } } = 3 and partially survives to the remnant center for \alpha _ { \mathrm { { \small TF } } } = 3.5 or 4 .
Global structural parameters evolve following trends similar to observations .
We show that the dominant mechanism for bulge growth is the inward flow of material from the disc to the bulge region during the satellite decay .

Conclusions : The models confirm that the growth of the bulge out of disc material , a central ingredient of secular evolution models , may be triggered externally through satellite accretion .